A Mechanic's Life - Tales From Under the Hood

thecardoc3 · November 2012

You're saying that using an oil with more VI improvers in it can cause all those things you mentioned - everything else in the oil being the same?

The confusion starts with the assumption that "everything else" about the two oils "is the same". Then it goes downhill from there at a rapid pace. The use of the word "approved" while I may not have written in every sentence is a very important part of this.

srs_49 · November 2012

You said "substituting a 5W-30 for a 5W-20 [oil]...". Most readers would assume that the only difference in those two oils is the VI numbers - that both are "approved".

And I agree that the term "approved" is most important.

explorerx4 · November 2012

Why would someone bring a 201 Fusion into your shop while it is still under factory warranty? and BTW, there's no such thing as a Fusion with a 2.0 until 2013.
Regarding the Lincoln, you must be a real softy for Fords, otherwise I can't see anyone feeling as obligated as you to fix it, other than Henry himself.

stever · November 2012

Maybe the runner from the Ford dealer drove it over when their service department couldn't get it working.

thecardoc3 · November 2012

The bulletin isn't clear which engines are in which cars, but it does include a 2.0 engine in the bulletin, and it does not include a 2.5.

Why would someone bring a 201 Fusion into your shop while it is still under factory warranty

It still has some warranty on some emissions components, but there are a lot of things that the warranty has expired on. The customer bought this car from Enterprise a little over a year ago. It's got 68K on it.

Regarding the Lincoln, you must be a real softy for Fords, otherwise I can't see anyone feeling as obligated as you to fix it, other than Henry himself

I own a few of them.

thecardoc3 · November 2012

Maybe the runner from the Ford dealer drove it over when their service department couldn't get it working.

Not this time, but it has happened a few times in the past, and not just with Fords.

explorerx4 · November 2012

I kind of figured the Fusion was out of warranty.
You didn't mention what model Lincoln it is.
Conti, LS, Navi, Town Car?

thecardoc3 · November 2012

Continental.

So I'm a little torn. Do I go ahead and and explain each of the diagnostics and the repairs right now or should I wait a little longer to see if the googlers want to try and make their guesses?

By taking the time and testing correctly the repairs were both quite simple, although there was more than one thing wrong with each of them and you do have to get all of the faults found or the car or it "would come back" and to that customer "you don't know what your doing". They may even decide that your not capable of solving the problem and want their money back for what you did do.

Tell you what, we can imagine that you actually did do some testing, whether you tried to rely on google or not. I'll wait a day and will answer up to three questions on each car. You'll have to ask the right questions but since there are several of you that could be a dozen or more questions from which I can choose from to answer. Now either google really works for diagnosing vehicle problems and you can do this or it doesn't.

Steve if you want, I'll email the answers to you, just don't open then email untill after we play this out.

If enough people try to work through these broken cars, I may even carry this further and answer a few more questions, provided they resemble testing and not guessing.

srs_49 · November 2012

OK, I'll bite.

You said the 2002 Lincoln (this is the one that's hard starting, right?) had several parts replaced already to the tune of $700 before it was brought to your shop.

Well, if its not trying to fire at all, my guess would be no spark or fuel. If you have both of those, then it should least try to do something. So I would first check to see if I have spark, then see if Im getting fuel to the fuel rails (weak fuel pump?).

stever · November 2012

Steve if you want, I'll email the answers to you

No thanks, just tell me what all 6,000 sensors say.

Oh, there's only 40 sensors in the car?

Well, there's your problem right there.

"Smarter machines, for example, can alert their human handlers when they will need maintenance, before a breakdown. It is the equivalent of preventive and personalized care for equipment, with less downtime and more output.

These technologies are really there now, in a way that is practical and economic, said Mark M. Little, G.E.s senior vice president for global research.

Today, G.E. is putting sensors on everything, be it a gas turbine or a hospital bed."

Looking to Industry for the Next Digital Disruption (NY Times)

It won't be long until your safety glasses will be telling you that your attention is lagging and to go take a break. (Wall St Journal)

xwesx · November 2012

I'm certainly interested in knowing what the issue was with the Lincoln and how you went about hunting it down. I've had a couple of vehicles with electrical gremlins that created hard or no start situations in the past. Neither were correctly diagnosed by multiple shops (nothing's more frustrating than spending money on having other people say, essentially, "I don't know"), though both were ultimately fixed. One was fixed as the result of another failure (or further failure of same part... I'll never know...), and the other was fixed by a flipper who had dealt with the same issue on many other of the same model vehicle.

In both cases, the vehicles were not getting fuel as the result of a circuit called the "automatic shutdown." The problem was determining why that circuit was open when it should have been closed. And no, neither online searches, literature, nor certified mechanics could get it fully right (or agree). :sick:

In the first case, a '96 Outback, the car's knock sensor failed eventually, with a code in the system also indicating intermittent faults on the cam sensor, so I replaced the knock, cam and crank sensors together (it had somewhere around 175K on it at that point). After that, no more no-starting issues for the rest of the car's life. The problem is that I'd had trouble with the no-starts since I bought it at 83K! :sick:

In the second case, a '98 Dodge Grand Caravan, the issue was a ground fault. The problem for me was that it was momentary, so I never found anything to be out of spec with the limited testing equipment I have, yet it was enough to set open the ASD relay when the car was turned on once in a while.

thecardoc3 · November 2012

Well, if its not trying to fire at all, my guess would be no spark or fuel.

Excellent, and you would be correct.

If you have both of those, then it should least try to do something.

Most of the time, and that of course is one of the keys that require techs to not only have the high tech tools, but that learned seat of the pants feel when it comes to doing diagnostics. That's why it takes decades to learn to be good at it.

So I would first check to see if I have spark, then see if Im getting fuel to the fuel rails (weak fuel pump?).

"Hint....The car starts sometime after the fuel pressure rises".

thecardoc3 · November 2012

Neither were correctly diagnosed by multiple shops (nothing's more frustrating than spending money on having other people say, essentially, "I don't know"),

I can think of something far more frustrating. Imagine spending a lot of time to correctly and succesfully analyze either of those issues, and not get paid for it. It happened to me so often in the past that the only solution was to quit working for other people who didn't understand nor respect what it genuinely takes to diagnose some problems. In a way, I'm taking that very same problem to task with this part of this thread.

though both were ultimately fixed. One was fixed as the result of another failure (or further failure of same part... I'll never know...), and the other was fixed by a flipper who had dealt with the same issue on many other of the same model vehicle

What's a flipper?

Today it's common to have to troubleshoot issues that we have never seen before and may never see a second time in our careers. That's one of the biggest failures with the idea of google diagnostics. Sure there are pattern failures, but relying on them is a trap that inexperienced techs often fall into. Just because there is a known issue or TSB for a given symptom you're doomed to fail eventually if you don't know how to test and prove that the failure is related to the one described in a given TSB.

In both cases, the vehicles were not getting fuel as the result of a circuit called the "automatic shutdown."

When I am teaching diagnostics I stress that it is important to understand a circuits operation in order to effectively troubleshoot a problem. When it comes to intermittent failures, you have to pre-plan a lot of your testing.
The ASD or "Auto Shutdown Relay" is Chryslers way of shutting down the fuel pump and a few other systems when the engine isn't running. It's convenient for them to interrupt not only the fuel pump but a number of opther circuits to reduce the load on the battery when the engine isn't running. Needless to say if you lose the command for the ASD, or the output from it the engine is going to stall because you just lost your fuel pump power, power to the ignition system and the injectors to name a few. The PCM only needs to see the crankshaft position sensor signal to command the ASD on. The PCM at key on will turn the ASD on to run the fuel pump for two seconds as well as perform a circuit check on the igniton coil circuits and the injectors etc.

Armed with that information testing needs to be done to prove if the reason you are losing the ASD output is because the PCM stops providing the ground control for it, or if the command circuit fails open. Plus testing needs to be done to prove if the supply power to the controlled side is lost when the circuit fails.

There is a little more to it, but this is the short version for how it would be approached. Then it's a waiting game to get it to act up. Each time it is then driven I would also be monitoring a scan tool so that I could watch and see if the PCM is recieving the crank sensor signal, as well as see if the PCM is commanding the ASD to be on or not.

In the first case, a '96 Outback, the car's knock sensor failed eventually, with a code in the system also indicating intermittent faults on the cam sensor, so I replaced the knock, cam and crank sensors together (it had somewhere around 175K on it at that point). After that, no more no-starting issues for the rest of the car's life. The problem is that I'd had trouble with the no-starts since I bought it at 83K!

While the base strategy is similar, Subaru uses a PCM relay and a circuit opening relay (fuel pump). The knock sensor failure would easily be a known failure that could be googled, or diagnosed with following the regular trouble tree in service information. It had nothing to do with the engine stalling. From there you simply "got lucky with the crank/cam sensor replacements. A DSO (digital storage oscilloscope) would have been a valuable asset towards proving what the failure was.

The problem with getting lucky is that you don't have any proof that you made a difference other than it simply hasn't acted up yet. If the car quits for any reason after that even if you did in fact fix it, as far as the customer is concerned it's still doing the same thing, you didn't know what you were doing and you failed to "fix" it.

In the second case, a '98 Dodge Grand Caravan, the issue was a ground fault. The problem for me was that it was momentary, so I never found anything to be out of spec with the limited testing equipment I have, yet it was enough to set open the ASD relay when the car was turned on once in a while.

By planning and presetting your test points and having the right equipment at your disposal this would be a very easy diagnosis, the first time that you experience one of these or the tenth time.

xwesx · November 2012

That's a heck of a response, Doc!

Let me see if I can hit the pertinent areas for mine.

Okay, so first, "flipper." That's someone who buys a car cheap, fixes it, and sells it for profit.

I stress that it is important to understand a circuits operation in order to effectively troubleshoot a problem.
And, therein was (and is) the root of my limitations when hunting down electrical gremlins. Without a circuit schematic and the training to understand it, one cannot possibly test thoroughly. Mine are pretty simple: This should be getting power, with this voltage, or that resistance across these points... is it? Yes. Okay. No, okay... what does that mean... ?

I can entirely understand your frustration of not getting paid for diagnosing something correctly. personally, I would have much rather taken that $350-400 I spent on nothing when my Outback first started acting up and put that toward a higher-in-the-end bill that resulted in a fully working car than having spent that money in vain.

With the Subaru, the problem I was fixing was more immediate: The car was running like crap due to no feedback (or bad feedback?) from the knock sensor. So, replacing the sensors was to get it to run well again. The no-start situation wasn't even on my mind, as I had learned to live with that long before. It wasn't until a month or two later, when I had yet to be stranded by the car while running errands, that I even started thinking, "wow, could it be that the August repair fixed this problem, too?!" I had the car to 220,000 miles (another 2+ years after that), and not once did I have a no-start after that. Before that, it would act up at least weekly, more often daily (or even more frequent).

With the van, I was dealing with multiple issues but didn't know it initially. The first problem was a fuel pump. I pinpointed that and replaced it, then the van was perfect again. The problem is, it stranded my wife (and our children) in a very awkward place, and she is not quick to forgive such things. So, after I fixed the fuel pump, she reluctantly took ownership of the van again (willing to give it a second chance). Then, two weeks later, this no-start thing begins. She says, "that's it, I'm done. I want a new car." *sigh*

She got her new car, which meant I then had no use for the van. I half-heartedly attempted to sort out the problem, but finally decided it wasn't worth my time and sold it to the flipper for a grand, who fixed the ground fault and sold it for $2,200 the next weekend. We both made out fine on that one, and I still see it tooling around town 2.5 years later! That's pretty good, considering it had 214,000 miles on it when I sold it.

----

I'd love to send my son to your shop for an apprenticeship just to watch you work. I bet he'd find the whole process fascinating.

stever · November 2012

Doc needs to hook up a live cam in his shop with a good mic so we can tune in anytime during working hours and admire his handiwork.

explorerx4 · November 2012

At first I was thinking leaky fuel injectors, but you didn't mention an expensive fix, so that's out.
How about a clogged fuel filter?

thecardoc3 · November 2012

Honest, hard work doesn't make a good reality show. On the other hand, train wrecks do. You won't find what we do as being able to garner much interest.

thecardoc3 · November 2012

At first I was thinking leaky fuel injectors, but you didn't mention an expensive fix, so that's out.

With the fuel pressure dropping after the pump turns off, that would be possible, but its easy to prove/disprove. The engine would be flooded (too rich) and holding your foot to the floor would interrupt injection command and that would allow the fuel mixture to lean out until the engine manages to start. It would be labored and missfiring at first and then clear up with a few throttle snaps. This car is not doing that.

How about a clogged fuel filter?

A clogged fuel filter is detectable by first watching fuel trims under heavy throttle load until you get such a throttle load that the computer commands an open loop acceleration, and then you simply need to watch the O2 sensors. If the O2 sensor voltages stay high, you're getting enough fuel. A clogged filter will cause a starvation for fuel when the engine is demanding the greatest amount of fuel per second. It is common to see fuel trims having to add a lot of fuel in both the long and short term corrections when the engine is under a load. When the engine is not under a load and fuel demand is light, the fuel trims don't need to correct as much. Watching that change in the trims makes the diagnosis easy.

This is neither a clogged filter nor leaking injectors. Leaking injectors would cause fuel trims to need to subtract fuel at low load conditon such as at idle in park/neutral, and the fuel trims would be closer to normal the higher the engine load becomes.

thecardoc3 · November 2012

I'd love to send my son to your shop for an apprenticeship just to watch you work. I bet he'd find the whole process fascinating.

Thanks. When I step in front of a group of techs as an instructor, I try to "bring them into the shop" to learn the routines that help me get through the day. Trying to watch me work though wouldn't be as interesting. To try and show what I am doing, while I work, leaves me splitting my concentration and has proven at times to be a very significant challenge. When I write a class I normally am collecting scope and scan data on one of my laptops, then I have to go back and take the photographs as a re-enactment of the process after the diagnosis has been completed.

The lady with the Durango that I diagnosed is supposed to pay for the diagnostics and tow the truck out. She doesn't have the 2K that it would take to repair it. That being said, where is she coming up with the 30K to replace it?

xwesx · November 2012

She doesn't have the 2K that it would take to repair it. That being said, where is she coming up with the 30K to replace it?

That doesn't seem to be an uncommon mindset, unfortunately. It's no big deal to go out and get a loan to buy a car, but $2,000 out of pocket? No can do.

Twice in the past I have "loaned" family members funds for an emergency auto repair, complete with generous repayment schedules, etc., and neither time did I ever see a penny from it. While I haven't held it against either of them, neither have they asked me for anything since then. At $1,200 each, maybe I won on those deals after all? :shades:

xwesx · November 2012

So, getting back to the Fusion, I think you said that the problem your customer had was not related to the P2111 code she was convinced was the problem, but instead due to her vehicle running off battery and draining down, correct? You also mentioned that the system was charging correctly after you charged the battery.

So, why did it drain in the first place? Was it somehow related to the 8-mile commute, since you did mention that? Or, the - nevermind. My wife is interrupting me and destroying my concentration. :mad:

thecardoc3 · November 2012

At $1,200 each, maybe I won on those deals after all?

I have only ever sold one "used" car and that one I never really owned, or at least used. I got it because of a random stalling issue that the owner simply didn't want to deal with and once I got to figure it out and fix it a friend needed a car and asked for it. He paid for the repair and enjoyed the car for a year. Then passed it onto his son-in-law who had it for another year, who gave it to a friend who crashed it.

Other than that one, I have given away every other car that I no longer had use for. There was never anything wrong with them as you can figure they get maintained to the max. I have a neice who will be getting her license in another year. I already know what car I will be giving her.

thecardoc3 · November 2012

So, why did it drain in the first place? Was it somehow related to the 8-mile commute, since you did mention that?

Yes.

So, getting back to the Fusion, I think you said that the problem your customer had was not related to the P2111 code she was convinced was the problem

The stalling was not related to the P2111, however she does in fact have an issue with the throttle body. Keep in mind the car is not repaired unless all of the issues are dealt with.

Now I'll give you one that will be really tough to swallow. The P2111 is basically caused by oil changes that used products that even though they were 5W20, don't actually meet the demands of the engin, or Fords specification.

kyfdx · November 2012

in the past I have "loaned" family members funds

Ah... otherwise known as a "gift"..

roadburner · November 2012

That doesn't seem to be an uncommon mindset, unfortunately. It's no big deal to go out and get a loan to buy a car, but $2,000 out of pocket? No can do.

I hear that all the time; "I need a new car because__________"
Fill in the blank:
"I need a car that gets better gas mileage"
"my car is old and things will start breaking"
"I can't afford to keep my old one running"

I once calculated that if I bought a car for $10,000(cash, no loan) plus my trade and the new car returned 16 more mpg than my old car it would take 7.5 years to break even- and that was assuming I drove 20,000 miles per year with a gas cost of $5.00 per gallon. Less annual mileage and cheaper fuel would move the break even point even further down the road...

The lady in the Durango may not be thinking that way, but 99% of the time "I NEED a new car." can be translated: "I'm bored and want something new."

stever · November 2012

neither time did I ever see a penny from it. While I haven't held it against either of them, neither have they asked me for anything since then.

If you get paid back be very careful. That just means they are going to hit you up in a few weeks for something even bigger.

explorerx4 · November 2012

Congrats, you got yourself a nice little graphic on the main Car Forums page!

thecardoc3 · December 2012

The Fusion. The main problem is all of the accessories draw some 140 amps of current, the alternator can produce 120amps as long as the engine is at or over 2000 rpm. Her communte has her "in town" for some 60% of her trip and the battery has to supplement the alternator's output when she is stopped in traffic. Over time this pulls the battery into a low state of charge because she simply doesn't drive it on the highway enough without all of the accessories on to ever allow the alternator to re-charge the battery fully, so the battery slowly sulfates and eventually dies. The car stalled because of the throttle plate sticking in the bore due to varnishes built up in it from the PCV gasses, and some reversion due to late intake valve timing under high efficiency mode. Once it stalled, the battery was simply too dead to allow it to start up and run on that morning. It had to have a new throttle body, and a software update for the PCM.

The Lincoln. This car fired right up the moment it had fuel pressure. During cranking the first thing that I found was the battery voltage dropped to 3-4v for an instant and then the engine cranked just fine, at 7.5v. At 7.5v the voltage was too low for the PCM to be turned on and command the fuel pump to run, that could leave you crank the engine until the battery was completely dead and it would never start. Charging the battery helped but it still tested as marginal and needed replaced but that wasn't the only issue. The batteries state was aggravated by the fact that the fuel pressure would drop as soon as the car was shut off. Fuel pumps have a check valve in them to hold pressure on the fuel rail and lines and this one has to be leaking. (that or maybe the hose that connects the pump to the fuel sender is leaking) Either way the longer the car was turned off, the longer it would take to prime the fuel system and get it to deliver fuel to the engine. If your cranking it the whole time you could be cranking it for five to ten seconds. If you didn't want to do that, by cycling the key on for two seconds, off, then on for two seconds would cycle the pump and the engine would fire up normally. The shop that sent the car over is going to service the fuel pump.

The check engine light on the Lincoln was an evaporative emissions leak and testing showed that the hoses and fittings that connect the cannisters at the rear of the car need replaced.

thecardoc3 · December 2012

That's pretty neat. It might get busier here now.

xwesx · December 2012

Dang. That's an impressively complicated set of conditions for both cars, but especially so for the Lincoln! The leak aside, it seems almost counter-intuitive that the battery would be weak given its ability to crank the engine for extended periods trying to get the thing to start.

I'm a little bummed that I didn't get a chance to respond on the Fusion's issue. I was thinking along the lines of the over-draw, but did not at all connect the throttle body issue to the no-start. I was thinking it was the charge issue that was causing the stall, which was throwing me off since you said the system was charging properly. I'm curious why the throttle body required replacement vs. cleaning if it was a varnish issue. And, what was it in the oil that would be out of spec to cause such varnish in the first place?

Finally, how does one determine what the overall amperage load on a vehicle is? I'm having an issue with my 2010 Subaru Forester right now (over the last year) in that it doesn't fully charge it's battery. Over the course of a few months, it gets to the point where I have to hook a charger up to the battery to fully charge it in order for the vehicle to reliably start for a few more months. While running, the voltage at the terminals is 14.4-14.6. The same symptoms persist regardless of the battery in the vehicle... batteries that work fine in other rigs, including my plow truck (which demands some major current and is used infrequently, at low speeds, and for short periods of time).

I was thinking it must be something to do with the charging system, but I cannot catch it behaving out of spec. The dealership was no help when I took it there last winter, as they simply told me the problem was due to my not having a heater on the battery for winter use. I explained to them that I don't use battery heaters on any vehicle, and have no problem with any of them (for years and years, including several other Subarus), but my request to actually investigate my concern fell on deaf ears.

Dealerships love battery heaters here, but my experience is that they only do a great job of nursing weak batteries so when you have to start the vehicle without the luxury of electrical access nearby, you end up stranded. :sick:

stickguy · December 2012

So, even modern cars need an "Italian tune-up" on occasion.

I have to remember to get my Volvo out on the highway on occasion. With my daughter driving it, it will be even more short hops than before.

thecardoc3 · December 2012

Finally, how does one determine what the overall amperage load on a vehicle is? I'm having an issue with my 2010 Subaru Forester right now (over the last year) in that it doesn't fully charge it's battery. Over the course of a few months, it gets to the point where I have to hook a charger up to the battery to fully charge it in order for the vehicle to reliably start for a few more months

The battery should be at an 80% state of charge. That's 12.5v with no loads after it's been sitting several hours to allow any surface charge to dissipate. I'm a little torn between explaining why it should not be at 100% (fully charged) and allowing some conversation to take place that would enhance the information. There are many myths out there that have stood for decades, and there are a lot of brand new strategies that are all about trying to increase the average longevity of the components as well as increase fuel economy.

Let's do it with me waiting for a bit before I put some effort into explaining why (approximately) an 80% state of charge for the battery is preferable to fully charging it.

When you have to hook up a battery charger to your Suby, is it because it's not cranking the engine correctly? What is the voltage at the battery terminals after it has sat all night? Has it been tested for an excessive parasitic drain? (30ma-50ma would be normal)

How far do you drive the vehicle for it's primary use? Is this highway use, or in town similar to my Fusion customer?

Try these numbers. (approximations, lots of variables here)
Headlights and parking lights. 15 amps
Ignition and computer syst. 11 amps
Fuel pump 8 amps
Heater Blower 20 amps
AC compressor clutch 4 amps
Heated Seats 8 amps (each)
Engine cooling fan 25 amps (each)
Entertainment / Inst Cluster 10 amps
Rear Defogger 10 amps
Windshield Wiper 15 amps (10 more for a rear one)

OK that's close enough for an average car. If you are running the majority of these items on your car on a cold damp morning that pretty much guarantees that there is little if not nothing left of the alternator output to go towards charging the battery when your on the highway. Then when you have to stop the battery is now responsible for providing most of the power and not the alternator to operate these systems.

A number of manufacturers have adopted load shedding strategies which helps explain why the BCM, HVAC, and other modules now control most of these functions. The engineers might have the HVAC controller slow the blower motor down to save power, unless the defrost setting is commanded. They may start out with the heated seats and rear defogger on fully, and then start pulsing the power to them after two to three minutes. Most of these systems only report (and possibly set a trouble code) if they have to go into a second stage of load shedding, the first stage is expected to be normal system operation. A three stage or greater load shedding condition will have the car doing things that the driver will notice.

Now take a longer trip. Most of the systems mentioned are either turned off or cycled off and the load on the alternator is reduced. That means more power is available to recharge the battery. The load shedding strategies also have the BCM, PCM directly calculating the batteries state of charge. These modules take into account the current that the battery has had to supply and the duration of the total discharge events. They also measure how much power the alternator has been putting out. Once the modules responsible for estimating the batteries state of charge decide that it should be back at the 80%, the charging system actually gets dialed back and the correct charging system voltage could be as low as 12.9-13.1v instead of the old 14.5v.

I was thinking it must be something to do with the charging system, but I cannot catch it behaving out of spec. The dealership was no help when I took it there last winter, as they simply told me the problem was due to my not having a heater on the battery for winter use. I explained to them that I don't use battery heaters on any vehicle, and have no problem with any of them (for years and years, including several other Subarus), but my request to actually investigate my concern fell on deaf ears.

Your Subaru is different from every other vehicle you have ever owned. I'll reserve comment about battery heaters because they are not commonly used around here, but battery temperature is very important and is measured either directly or indirectly.

imidazol97 · December 2012

>y these numbers. (approximations, lots of variables here)
Headlights and parking lights. 15 amps
Ignition and computer syst. 11 amps
Fuel pump 8 amps
Heater Blower 20 amps
AC compressor clutch 4 amps
Heated Seats 8 amps (each)
Engine cooling fan 25 amps (each)
Entertainment / Inst Cluster 10 amps
Rear Defogger 10 amps
Windshield Wiper 15 amps (10 more for a rear one)

Are engine cooling fan(s) left on when car speed reachs a nominal point where air flow is adequate for cooling through the radiator and/or condenser? Are those turned off at say 40 mph?

thecardoc3 · December 2012

Are engine cooling fan(s) left on when car speed reachs a nominal point where air flow is adequate for cooling through the radiator and/or condenser? Are those turned off at say 40 mph

Yes, in fact the cooling fans usually turn off at speeds as low as 25mph. That's part of the variables mentioned. At highway speeds the alternator can produce more power because it's being driven faster, and then at idle when the alternator cannot produce as much power we get the load from the cooling fans.

xwesx · December 2012

Thanks for that reply, Doc.

When you have to hook up a battery charger to your Suby, is it because it's not cranking the engine correctly? What is the voltage at the battery terminals after it has sat all night? Has it been tested for an excessive parasitic drain? (30ma-50ma would be normal)

How far do you drive the vehicle for it's primary use? Is this highway use, or in town similar to my Fusion customer?

I tend to hook it up after noticing the starter cranking "differently" than normal. Subaru starters are, for lack of a better way to describe it, "slower" than most other cars. I've owned Dodge (one only), Ford, and Chevy vehicles as well, and they all crank significantly faster than all but my '96 Subaru. It doesn't seem to impact whether they start or not, but rather it is just a feature of the car.

But, when the slow cranking turns to a cranking that includes a slight pause into the rhythm, then I know it's not right. Upon checking the battery voltage, it is always under 12 volts in this situation (generally about 11.95). The car still starts in the warmer months, but in the dead of winter there's enough system resistance (included the added CCA demand on the battery) to keep it from starting. Now, if I had a battery warmer, it might just start the car in those conditions, but it still wouldn't help for when my wife starts the car when leaving where ever it was she went. Personally, I'd much rather she be stranded at home than somewhere else!

Yesterday I charged the battery (not fully, meaning the charger had not turned itself off automatically) and it tested about an hour later at 12.56 volts before I started the car, drove into town with the kids, and made three stops before driving home. The ambient temperature was -27F. We drive with the headlights, etc., on all the time. The radio was on, the interior blower fan was on full, and the driver seat heater was on its lowest setting. (The engine cooling fans generally don't run at all this time of year, as passive air flow through the front of the car and the interior blower sucks of plenty of heat.) The longest distance we drove was a little over 8 miles (a typical run for us is probably 10-15 max), with six of those being unencumbered highway miles, and the last two being mild stop/go. We had no problems with the car starting, etc., while we were on our trip over the course of three hours (drove to one store, left an hour later, etc., three times).

Today when I checked the battery, it read 11.98. :confuse:

We don't need the car today, so I didn't have the block heaters on and therefore I didn't try to start it.

Your Subaru is different from every other vehicle you have ever owned.

Why so?

srs_49 · December 2012

Sounds like there's a lot of room for improvement in a lot of the functions you mentioned. Looking at it from a power standpoint we get for some of the items:

130W for the ignition and computer system
240W for the heater blower
300W for each fan motor
96W for the fuel pump motor

Back to the Fusion, sounds like the its charging system was under designed.

thecardoc3 · December 2012

Open circuit voltage that is less than 12.1 v is a dead battery.

To fully charge it back up would take 1.5 times the reserve capacity rating at 25amps. If the reserve capacity is 120 minutes, that means you need to charge the battery for 180 at 25 amps. The problem is, the charger won't stay at 25 amps, as the batteries state of charg increases, the chargers output decreases. Here is how it works. 180/60 x 25 = 75amp/hours
If your charger outs out 7.5 amps, then it would take ten hours to charge the battery. If it's five amps now you need fifteen hours.

The big battery chargers that we use will start out in the 30-40 amp range but again don't stay there very long, maybe twenty minutes. Then they drop into the 20 amp range and by the end of the first hour we are down to 10-15 amps.That means we are looking at a five to seven hour time frame to really bring a battery all the way back, and we have to do that without overheating it and/or gassing it.

I'd be looking very closely at your Suby for a parasitic drain, and I would be testing that battery carefully. Just like keeping a battery at a low state of charge can kill it by causing sulfation, over charging it kills it by boiling off the electrolite, or by breaking the water of the electrolite down into H2 and O2. I would not be surprised to hear that your battery fails testing, but make sure that you try to find out if something about your car killed it.

As far as your Subaru being different, it isn't as sophisticated as a lot of cars are today, but the charging system has a lot more things that it has to do very precisely today than it did just a few years ago. I'll look up some specifics when I have the chance.

xwesx · December 2012

I put the charger on it today at about 11:30am. It charges at three preset outputs: 2A, 4A, 6A. I set it on the 6A output and it ran about five hours before shutting itself off. When I went out to check on it and it was off, the battery read 12.56 volts. Just now, three hours later, I took another reading and it was at 12.16 volts.

So, it looks like this saga is just beginning. :mad:

To start, I should probably get a manual cut off switch to eliminate parasitic draw until it can be identified, and then put the original battery back in the car so that my good batteries don't keep getting tortured by the car. I'd much rather lose the stock Panasonic battery to being chronically undercharged than the very nice (and very expensive) Optima Redtop that I put in it last winter.

Now that I'm thinking about parasitic draws, I noticed last summer when I used my trailer that the running lights on it did not turn off when I shut off the car. Maybe the place to start looking is in the trailer wiring circuit. These cars come pre-wired for a "T-connector" 4-way trailer wiring set up, but all those wires just hang out under the flooring of the cargo area....

thecardoc3 · December 2012

I put the charger on it today at about 11:30am. It charges at three preset outputs: 2A, 4A, 6A. I set it on the 6A output and it ran about five hours before shutting itself off.

At best you got 30 amp/hours towards the battery, which means it would really have gotten about 20 amp/hours into it. It takes 1.5 times the reserve capacity to fully recharge a battery that was dead. The problem is your charger doesn't stay at 6 amps the whole time, and it was probably down to about three amps for the last three hours. That means, and your open circuit voltage agrees, your battery is only at about a 30% state of charge.

To start, I should probably get a manual cut off switch to eliminate parasitic draw until it can be identified, and then put the original battery back in the car so that my good batteries don't keep getting tortured by the car. I'd much rather lose the stock Panasonic battery to being chronically undercharged than the very nice (and very expensive) Optima Redtop that I put in it last winter.

I don't expect the Subaru to be as picky as a number of cars these days, but lets take BMW for an example. When you replace a battery you need to tell the BCM exactly what battery you put into the car, that way it can correctly calculate the batteries state of charge. The car needs to also start with the battery at a full state of charge and it allows that to be dropped to the 80% range as I mentioned earlier. So why 80% and not 100%?

A battery is a big capacitor as well as an energy storage device. By keeping it at 80% it has the ability to absorb many of voltage spikes that naturally occur on a car. Voltage spikes can disrupt communication between modules or cause false sensor readings and cause all kinds of issues. Another reason is by trying to charge a battery to 100% you will quite often overcharge it and that damages it. There is actually even more to it, but that's enough for now.

When I went out to check on it and it was off, the battery read 12.56 volts. Just now, three hours later, I took another reading and it was at 12.16 volts.

You should have put the charger back on overnight. That might have gotten the battery back to about 50%. About 12.3v

To start, I should probably get a manual cut off switch to eliminate parasitic draw until it can be identified

Nope, that's the wrong idea today. Depowering the car can cause it to lose a number of trained functions (auto power windows for one), trouble codes, adaptive strategies such as fuel trim and transmission shift compensations. You need to measure the system's draw and if it's excessive go find it, and that does not mean off the wall guesses like :

Now that I'm thinking about parasitic draws, I noticed last summer when I used my trailer that the running lights on it did not turn off when I shut off the car. Maybe the place to start looking is in the trailer wiring circuit. These cars come pre-wired for a "T-connector" 4-way trailer wiring set up, but all those wires just hang out under the flooring of the cargo area

Sometimes a guess like that can be correct, and that's fine because a proper testing routine will lead you right to it anyway. However most of the time they guesses are simply a waste of time and cause lots of frustration. We teach techs electronics and voltage drop testing based on ohms law. With that they then understand that if there is any current flowing in a circuit, then the voltage applied to it will have a drop as it flows arcross a resistance. A fuse is a resistor, so any parasitic drain will cause a small voltage to be measurable across the fuses terminals. Do you have a voltmeter that is accurate into the 10,000ths of a volt or smaller? (.000XX) That is how you go about locating what circuit the drain is on. A low amps probe allows a technician to measure the drain on the car without opening the electrical system and clearing out all of the memories as well. Some of those are accurate down to about 5ma (.005 amps).

On a side note, last week I got a call from a lady who has been to Autozone several times in the last few weeks. They already replaced her battery, twice, and have done electrical tests on the car and can't find anything wrong. Her battery keeps going dead, usually over a weekend, but after a couple times then its dead every day and has to be jumped.

The call was on the shops answering machine, you see I was out teaching that day as I do that to subsidize our income from the shop. The tools and equipment that we need to have in order to do everything required of us today are so expensive that the shop cannot support them and have us earn a living too. The last two years the shop accounted for about 30K net profit for the 50-60 hours each week that we put in there. We made our living essentially from the teaching income.

Had we of been her first call and especially if we had gotten the easy work too, we could have made a reasonabe return for the effort required to be "Service Ready" for her vehicles problem. Plus we also would have solved it on the first visit and it would have been a non-event from our perspective. Now it's a nightmare for her because for all the times the parts stores get away with those battery sales (and a lot of the other things they are doing) the loss of oppertunity to us eventually has made enough of a difference that we weren't there when she needed us.

The tough part here is should we take her in and fix her car or not? I haven't called her back yet, first of all we have been booked solid, that's the advantage of shutting down two days in the middle of the week, I get to be much more productive the rest of the time that we are in the shop instead of having a lot of idle time. Even if I bring her on and fix this for her history has shown that she is not likely to be come a permanent customer. She started out at the parts store with this problem because everything the consumers have ever been taught is how the cheapest price is all that really matters, right up until that routine fails. Then in some ways it doesn't matter what we charge, "it's too much" so the only way we ever see them again is in five or six years when they have another nightmare that no one else seems to be able to solve. :sick:

xwesx · December 2012

I certainly see your point regarding the problems associated with "taking" a call like that. While I like to try to solve my vehicles' issues, I also don't have a problem with taking it to a shop for repair when I can't figure out the problem. For me, though, I want the problem solved if I do take it in, and my past experiences are that with electrical issues, shops tend not to solve the problem. That, of course, creates a negative feedback loop in which I am more reluctant to take it in and instead become more stubborn about figuring it out.

I should note that the last time I took a car in for such an issue, the shop did solve it. Of course, it turned out to be plug wires, and I'm still kicking myself over that one, but I didn't even check them because they were only a couple years old. Since I already convinced myself that it was something else, I looked at everything else I could think of and couldn't find a problem.

I guess I should have fallen back to the mantra of my profession: Trust, but verify.

----

Okay, so back to my car. Good point about the system memory. I should remember that this is a "new" car. Part of the issue with testing right now is that the temps are at -30F and lower (no garage here!), so I'd like to push things off to warmer weather so I don't risk breaking plastic things (or getting frostbite).

I did two things last night: 1, I disconnected the T-connector from the factory trailer wiring plug just because it was on my mind. 2., I put the charger back on it last night and let it charge over night (~12 hours) on the "slow" (4A) setting. At 0730 when I checked it, the charger had shut itself off again saying the charge was complete, and the battery read 13.06V.

I'll check the voltage again when I go home at noon to pick up my daughter for school. I have the car plugged in (block/oil pan heaters) right now, though, and expect (based on its prior behavior) it will start for my wife at 3pm this afternoon.

As for my tester, I think it goes that small. it switches between a mV reading and V reading automatically, and displays tenths in the mV setting, so theoretically it will. It's only a $35 Innova unit, though, so I'm not sure how accurate it'll be.

thecardoc3 · December 2012

As for my tester, I think it goes that small. it switches between a mV reading and V reading automatically, and displays tenths in the mV setting, so theoretically it will. It's only a $35 Innova unit, though, so I'm not sure how accurate it'll be.

You should be using a meter with an accuracy of .1% +1

srs_49 · December 2012

On measuring parasitic current draws-

You said to measure the voltage drop across the fuse, then calculate the current from that and the resistance of the fuse.

Question - how do you measure the resistance of the fuse without removing it from the circuit? Do you just measure a fuse in the parts bin, and assume it's close enough to the one in the vehicle?

If you have to remove the fuse from the vehicle, then aren't you right back at the issues you raised with opening up the circuit to insert a current meter? Unless you jumper around the fuse before pulling it out to measure it's resistance.

Could use a non-invasive current (Hall Effect) probe, providing you can clamp it around the wire of interest.

Just thinking out loud...

obyone · December 2012

Even if I bring her on and fix this for her history has shown that she is not likely to be come a permanent customer. She started out at the parts store with this problem because everything the consumers have ever been taught is how the cheapest price is all that really matters, right up until that routine fails. Then in some ways it doesn't matter what we charge, "it's too much" so the only way we ever see them again is in five or six years when they have another nightmare that no one else seems to be able to solve.

I think you've answered your own question though you won't know for sure unless you go ahead and repair it. On then will you be certain whether she will be a loyal customer or not as we never judge a book by its cover.

In this case, I'd agree and unless it's real slow I'd pass on it.

thecardoc3 · December 2012

Question - how do you measure the resistance of the fuse without removing it from the circuit? Do you just measure a fuse in the parts bin, and assume it's close enough to the one in the vehicle?

Actually what I said was.

A fuse is a resistor, so any parasitic drain will cause a small voltage to be measurable across the fuses terminals. Do you have a voltmeter that is accurate into the 10,000ths of a volt or smaller? (.000XX) That is how you go about locating what circuit the drain is on. A low amps probe allows a technician to measure the drain on the car without opening the electrical system and clearing out all of the memories as well. Some of those are accurate down to about 5ma (.005 amps).

Could use a non-invasive current (Hall Effect) probe, providing you can clamp it around the wire of interest.

So the answer is yes, measure the current draw, and if it's excessive use can use the voltage drop technique to identify the circuit.

Question - how do you measure the resistance of the fuse without removing it from the circuit? Do you just measure a fuse in the parts bin, and assume it's close enough to the one in the vehicle?

It is possible to measure the resistance of a fuse with the correct tools but a regular ohmmeter isn't the correct tool. Besides, it's easy to calculate the fuse's resistance by measuring the current through it, and the voltage drop across it. The fun part about this is the fuses resistance isn't fixed. Like anything else the temperature of the fuse makes quite a difference in it's resistance, which of course explains exactly how they work when you think about it for a few moments.

bartbarter · December 2012

I read this entire thread and wanted to say thanks for all the great info.

And insight. I'm a backyard hack, but a stubborn one, so I only use a garage occasionally. But when I do I'll look at it a little differently now.

The only thing I have to add is, don't buy the cheap rotors!! Even if you're lucky enough to not get the ones that shatter, I was buying $13 fronts for my old 97 Grand Marquis and had to replace them more often than the pads! Also, while the rotors on my 03 are hatless, because they are so much bigger than the 'hatted' rotors on my 85 Town Car they seem to weigh about the same.

Bartbarter

stickguy · December 2012

good point about the parts, and I will bet that "doc" will agree. Not worth buying cheap parts, unless you like to replace them and do your own work. and have lots of spare time.

but when you are paying to have a job done, usually (or at least often) the labor is the biggest part of the job. So saving a few dollars on an inferior part seems counter-intuitive to me.

oldbearcat · December 2012

Where I live, the past few times I've replaced the tires on my vehicles, I've had to take the car back 3 - 4 times for a re-balance for the shop to get them properly balanced. I've had this problem with local independents and national chain tire dealers as well. My most recent experience - I recently replaced all 4 tires on my Honda CRV. I've had the car back to the shop 3 times for a re-balance and they still didn't get it right. Monday I took the car into my local Honda dealer for a brake job, and, had them balance all 4 wheels as well. The Honda techs got the wheel balance right on the money. Is there a shortage of folks who know how to mount and balance tires correctly? Around here the only places that I currently know that will get it right the first time are my local Honda and Mercedes Benz dealers. I'm tired of sitting in waiting rooms for hours while they make multiple attempts to balance the tires correctly.

Regards:
Oldbearcat

stickguy · December 2012

My guess, a combination of poorly trained low paid techs, the need to get them done quick, and the ever increasing size and weight of the wheels/tires all come into play.

thecardoc3 · December 2012

My guess, a combination of poorly trained low paid techs, the need to get them done quick, and the ever increasing size and weight of the wheels/tires all come into play.

Many of the chain stores pay their techs an hourly wage, plus a bonus based on productivity. Then they turn around and exclude some items from the list from which they accumulate productivity. Guess what one of those items is?

In essence, the techs are "punished" for doing tires, unless they upsell other services from the tire replacement. Then in the case like bearcat, since techs are not paid for a "comeback", they are in effect punished again. The only recourse is for the techs to minimize the personal financial hit by not being paid for installing tires and that happens with speed. When everything goes correctly, nobody else cares what actually happened inside the shop.

Now as far as balancing the tires, there are problems with some wheels on some balancing machines. The wheels have to center correctly in order for the machine to be accurate and many manufacturers have an uncanny ability to make sure their wheels don't mount up without specific adapters. My machine (Snap-On) doesn't do a lot of the 3/4ton truck wheels as easily as it does any car steel wheel. Some of the Jeep mag wheels force me to be very creative in double, and triple checking the wheel/tire assembly which often means that I have to spin it to measure it out, add the weights to balance the assembly and re-spin it to check it. The I have to break it loose, turn it on the spindle and then tighten it up and re-check it again. There have been a number of times that I have found that I have to use different adapters between individual wheels from one car. If the wheel is balanced correctly, I should be able to take it loose, reposition it, and tighten it back up and end up with "0's" again.

The advantage for me is that I don't have to rush through a job like this. I'll take whatever time I need to and in some cases I have had to buy additional adapters for my machine.

obyone · December 2012

Notice the difference?

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