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A Mechanic's Life - Tales From Under the Hood

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  • steverstever Viva Las CrucesPosts: 41,902
    So, was the sludgemobile a '98-'04ish Chrysler/Dodge? Same era Hyundai or Saab. Or VW?

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  • thecardoc3thecardoc3 Posts: 1,632
    2004 Nissan Altima 2.5l
  • steverstever Viva Las CrucesPosts: 41,902
    My Nissan's VG33E V6 is much better than that QR25DE 4 cylinder. :D

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  • xwesxxwesx Fairbanks, AlaskaPosts: 8,677
    I came up with a reasonable solution to the OCI vs. oil life problem. I use oil analysis to determine an optimal OCI for my car given my vehicle, driving conditions, and oil type. That way, I don't have to guess as to whether my engine is healthy and being properly protected by the oil that lubricates it.

    On an entirely separate note, I haven't had any issues at all with my Forester's battery since disconnecting that trailer wiring harness and recharging the battery. Assuming no more issues this winter, I'm going to have to do some more testing on that wiring come spring. But, at least my car starts reliably for now. Many thanks to Doc for the guidance (on that and in general). I'll have to drop some cash in his tip jar when I go through PA next September. ;)

    Merry Christmas, folks! I'm sure many are beginning their holiday travels, so stay safe out there.
    2010 Subaru Forester, 2011 Ford Fiesta, 1969 Chevrolet C20 Pickup, 1969 Ford Econoline 100, 1976 Ford F250 Pickup, 1974 Ford Pinto Wagon
  • thecardoc3thecardoc3 Posts: 1,632
    How did you determine a slipped timing chain, for certain?

    Once you understand it, which takes a lot of studying, and then the investment for the pressure transducer set-up and a state of the art oscillosope it's pretty easy.

    I uploaded some screen shots from my scope on my facebook page. These compression waveforms are taken engine cranking, engine running, and snap throttle. The ones you will see on my page are cranking and I used them to demonstrate a new routine that I figured out to everyone else.

    When we first learned to use the pressure transducers, the fellow who figured it out felt that the cranking waveform wasn't reliable to determine valve opening/closing events. That is because you have to have manifold vacuum to create specific cylinder pressure changes during parts of the engine's cycle. A few months back I realized that all I need to do to get sufficient vacuum when cranking the engie that won't start to see all of the valve train events was to restrict airflow into the engine. In the case of the Nissan, I could do that with my hand over the throttle body inlet.

    It worked beautifully, then it was simply a matter of measuring out the waveform that the cylinder produced. The exhaust cam timing should be slightly advanced on this engine as compared to other engines. On the captures it looks like its real advanced because with it cranking the engine is turning slow enough that the rise in pressure in the cylinder caused by the exhaust valve opening completes before we reach BDC. Then the cylinder pressure drops after the intake storke starts, but not until the exhaust valve closes. The next part of the waveform that is critical to show exactly what the problem is occurs at the point where the cylinder pressure starts to rise in the cylinder as we have the compression phase. That doesn't occur until 76 degrees of crank rotation after BDC. That's retarded, it should have occurred about 30 degrees after BDC.

    Here is my page.

    http://www.facebook.com/john.gillespie.127648
  • thecardoc3thecardoc3 Posts: 1,632
    Almost forgot, I also grabbed waveforms of the cam and crank sensor signals, both cranking which shows the cam signal really distorted because of the chain slop allowing the cam to not be held in time, I also disconnected the cam sensor, which allowed the PCM to turn the igition system on and let the engine run. The PCM shuts the igition system down if there is a cam/crank sync issue to try and protect the engine from further damage. Once the engine was running, capturing the camshaft and crankshaft signal waveforms allowed them to also be compared to known good captures, and that again proves that the intake cam is out of time.
  • Mr_ShiftrightMr_Shiftright CaliforniaPosts: 45,945
    Where are the pressure sensors located when you're cranking?

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  • thecardoc3thecardoc3 Posts: 1,632
    Right on the hose that would usually attach the pressure gage to the cylinder. One of the important differences is this hose does not have a schraeder valve in it, that allows the transducer to sense everything that is occurring in the cylinder.
  • Mr_ShiftrightMr_Shiftright CaliforniaPosts: 45,945
    How could this system be fooled?

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  • thecardoc3thecardoc3 Posts: 1,632
    How could this system be fooled?

    I don't understand your question.
  • Mr_ShiftrightMr_Shiftright CaliforniaPosts: 45,945
    How could it miss the problem...how accurate is it in other words...e.g., does it work for turbo engines, or diesels, or ??? OR could the results actually show two separate problems at once, so that the tech could not know which one it actually is?

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  • thecardoc3thecardoc3 Posts: 1,632
    How could it miss the problem...how accurate is it in other words.

    The biggest issue a tech faces when learning to test at this level would have to do with the speed and accuracy of the transducer used. The top of the line stuff, ATS, and PICO work great. There are less expensive versions that still work but response time and scaling issues can arise.

    But how accurate is it? It is the most accurate way to test how a cylinder is operating than we have ever had available to us.

    ..e.g., does it work for turbo engines, or diesels, or ???

    Yes, yes, and well we can use it for diagnostics with any system that has changes is pressure that can provide us with useful information. That means we can use them in the exhaust, or with manifold vacuum. Fuel systems, actually see how each injector affects the system fuel pressure. AC systems, Transmission controls, you name it it can be of assistance.

    OR could the results actually show two separate problems at once, so that the tech could not know which one it actually is?

    Given enough chances could you misread a tire or compression gage? The great part of testing like this is how easy it is to make a permanent record of the testing results, which is where the Nissan captures came from.

    Now could a cylinder have more than one issue, sure why not? If the valves are bent and not sealing, and there is a hole in the top of a piston, your not going to have much compression, but it would in fact still have pulses of pressure just from any air movement. A smaller range transducer would be needed to give a tech a lot of resolution, and from there it's going to be a matter interpretation of the wave form that gets produced. Then the tech would need to perform different testing, I.E. borescope or attempt to pressurize the cylinder to see where he/she finds the leakage.

    Beyond an extreme case like that the routine works well to prove broken valve springs, or cylinder leakage where the tech already knows exactly where the compression loss is at, and can simply use a second test such as cylinder leakage for conformation. One of the coolest uses is exactly what I demonstrated with that Nissan. Without tearing the engine down, the intake cam is definately out of time. This engine uses a chain with marked links to set it up. That means you can't just dissasemble and turn the engine to try and line them up, unless you have the time to try and turn it over by hand some 200 times (maybe) to get the timing links to hunt back to their original positions. Worse yet, with varible cam timing, and camshafts that don't have keyways to the cam gears (which means the gears can turn on the cam), or camshafts that are tubes that have the lobes pressed on (which means individual lobes can move) a tech has to have a way to know what is wrong before doing several hours worth of tear down. This kind of testing solves that problem.

    Here is the website for the guy that first figured this all out and there are some educational case studies on this link.

    http://www.automotivetestsolutions.com/pressuretransducersarticle.htm

    BTW, this is just one of the tricks that we use today when it comes to working on the cars efficiently, there are more, lots more.
  • Mr_ShiftrightMr_Shiftright CaliforniaPosts: 45,945
    This from Ford:

    "With more than 145 actuators, 4716 signals, and 74 sensors including radar, sonar, cameras, accelerometers, temperature and even rain sensors, the 2013 Fusion can monitor the perimeter around the car and see into places that are not readily visible from the driver’s seat. These sensors produce more than 25 gigabytes of data per hour which is analyzed by more than 70 on-board computers. "

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  • thecardoc3thecardoc3 Posts: 1,632
    These sensors produce more than 25 gigabytes of data per hour which is analyzed by more than 70 on-board computers. "

    And that is just one of the onboard systems that are serviced, diagnosed and repaired by technicians just like me. Adaptive cruise control and parking assist systems should make the readers realze just how much robotics has entered our trade.
  • Mr_ShiftrightMr_Shiftright CaliforniaPosts: 45,945
    All totally useless gadgetry if you ask me. These features are in a sense just a hidden expense piled onto car ownership. Not only is it ridiculous that a passenger door lock actuator costs me $180 for the part, but equally ridiculous that I need a 5 year-old's fingers and a remote snake light, to replace it. Gee, I would have gladly accepted a door key on the passenger door, and thus ignored the broken actuator all together.

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  • thecardoc3thecardoc3 Posts: 1,632
    So who held the gun to your head and forced you to buy a Mini Cooper?
  • xwesxxwesx Fairbanks, AlaskaPosts: 8,677
    That's the way with any new car today, not any one brand. Things like manual locks and window cranks just don't exist any longer. It's been a couple decades since anything other than front doors have had outside door lock tumblers, and at least five since there was more than only a tumbler on the driver door.

    Most of this peripheral stuff isn't making cars better, it is only making them easier to drive (which means drivers are becoming less capable). :sick:
    2010 Subaru Forester, 2011 Ford Fiesta, 1969 Chevrolet C20 Pickup, 1969 Ford Econoline 100, 1976 Ford F250 Pickup, 1974 Ford Pinto Wagon
  • Mr_ShiftrightMr_Shiftright CaliforniaPosts: 45,945
    edited December 2012
    Well it's a blast to drive. I figured that being German designed it would be designed intelligently. I figured that for almost $30,000 MSRP (I didn't buy it new, thank God), you'd GET a door lock on the passenger side. Or armrests. Is that too much to ask---armrests?

    A car doesn't have to be impossible to repair---designers could help the mechanic out in so many ways.

    Now really, almost 13 hours to replace a clutch disk? I could probably have R&R'd an engine from a World War II bomber in less time than that.

    In the Army we used to use an M18 Claymore mine. I'd probably keep one in my toolbox if I were a technician today and had to blast my way into a MINI clutch. :P

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  • steverstever Viva Las CrucesPosts: 41,902
    If you were recently denied auto warranty coverage for a surprising reason, please email PR@edmunds.com no later than Wednesday, January 9, 2013 to tell your story to a reporter.

    Now back to our regular programming....

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  • thecardoc3thecardoc3 Posts: 1,632
    All of my cars come with a lifetime warranty guarantee.

    If one of them ever breaks in my lifetime you can guarantee I'm the person who will be repairing it. Frankly I wish I could sign off and exclude all possible warranty expenses and get a break on the purchase price for doing so.
  • thecardoc3thecardoc3 Posts: 1,632
    edited December 2012
    A car doesn't have to be impossible to repair---designers could help the mechanic out in so many ways.

    Why do that when they can invent yet another fastener, and then make royalties off of the tools that a mechanic needs to work with it too?

    There is one theme that often gets overlooked. The O.E's can sell more cars if mechanics/technicians can't efficiently keep the older ones on the road. Everything that targets shops/mechanics and limits our growth as businesses or individuals ultimately serves to shorten the effective lifespan of any vehicle. (Yes that even encompasses the DIY'ers) From the simple perspective of "It isn't worth what the repair will cost" you have a tide that pushes the owner towards yet another new (or newer) vehicle.

    In a nutshell that means they don't care about what it takes to service a car. I had the cylinder head off of a Saturn Vue. I got to use a couple of sockets that have been in my tool box for almost a decade for the first time with that repair. That was the upside, the downside is that the machine shop didn't find that the cylinder head was cracked when they pressure tested it. The crack is in the #4 spark plug hole and after the head was back on and the car run through a few cycles became very evident.

    The #$%^& head held pressure when it was tested, but now the crack is so big it leaked with no pressure at all so off it came, again. That's a lousy result any time, but it's costing me a lot more than a headgasket. All of the cylinder head bolts, the crank pulley bolt, and both cam gear bolts are all TTY. All told the cost to redo this is over $350 in materials, and then there is the loss of about eight hours in labor.

    Well it's a blast to drive. I figured that being German designed it would be designed intelligently. I figured that for almost $30,000 MSRP (I didn't buy it new, thank God), you'd GET a door lock on the passenger side. Or armrests. Is that too much to ask---armrests?

    BTW, I just added another scan tool to my collection, it is targeted at improving my ability to service Euro vehicles. This tool combined with my J2534 support will let me be about 90% capable on Mini, and most of the BMW line. This also will get me close to that level on Rover, Jaguar, Mercedes, etc. But that also means I'm going to be headed back into intense study mode. The tool is worthless without the technical education that goes hand in hand with each manufacturer. (That tool is going to cost me $240 a month for the next three years)
  • steverstever Viva Las CrucesPosts: 41,902
    The O.E's can sell more cars if mechanics/technicians can't efficiently keep the older ones on the road.

    Good in theory but cars sure last a lot longer than they did in the 70s. And the average age of cars on the road keeps going up, in good times and bad.

    And if the manufacturers don't design parts for a ten year lifespan, the three year failure rate will be so high that they'd lose money on warranty claims.

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  • thecardoc3thecardoc3 Posts: 1,632
    And if the manufacturers don't design parts for a ten year lifespan, the three year failure rate will be so high that they'd lose money on warranty claims.

    First who ever said that any warranty work is free to the consumer. You paid up front for any warranty as part of the purchase price. Then we have the obsolescene side of the picture. Do you ever try and track how many parts are "obsolete" from the O.E.'s on cars that are less than ten years old?
  • steverstever Viva Las CrucesPosts: 41,902
    The manufacturers lose money if they have to pay too many warranty claims. There's all kinds of information and graphs about the subject at warrantyweek.com.

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  • explorerx4explorerx4 Central CTPosts: 9,972
    right in my own town
  • thecardoc3thecardoc3 Posts: 1,632
    The manufacturers lose money if they have to pay too many warranty claims.

    Ah, yea that's how it works. And if they have fewer warranty claimns than they budgeted for rthen they make $$$$$$

    There's all kinds of information and graphs about the subject at warrantyweek.com.

    If you really know the automotive business then you know that the one thing that cannot be trusted is a number that someone else writes down. :shades:
  • steverstever Viva Las CrucesPosts: 41,902
    The editor over there gleens info from corporate reports. They may be off, but the SEC and other regulators frown on lying on the forms. With all the complaints about various cars, the bottom line seems to be somewhere between 2 and 3 percent of owners will suffer some problem. Not a huge number in the overall scheme of things, but if it's your transmission or AC compressor that goes out, it's a major pain.

    We really should be asking you what car (or brand) to buy and which one to absolutely avoid at all costs. ;)

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  • thecardoc3thecardoc3 Posts: 1,632
    Labor guide gives .8hr for valve cover gaskets, 1.2hrs for ignition wires and 1.4hrs for spark plugs.

    The labor guide also allows for 2 hours to adjust the valves, which are manually adjustable and is not a lot of fun to do.

    The part that doesn't make any sense is the lack of consideration for overlapping operations. The spark plugs are inside of tubes that pass down through the valve covers. So if you are going to remove the valve covers to replace the gaskets, the spark plug end of the plug wire has to come off anyway. Not to mention that once the valve cover is off, the spark plugs themselves are as easy to reach as they will ever be with the engine still in the car. The entire job, including adjust the valves which obviously wasn't done would be about 2.5hrs in my shop and that's $196.92 labor. The iridium spark plugs are a good choice and the $11.00 (approx) would be typical. Top of the line plug wires are pricey and are somewhere in the $80.00 range. So $44.00 plus, $80.00, plus $197.00 equals $321 plus sails tax. That's the real price, minus the oil change that any of my customers would get quoted and I have to compete in the marketplace with people who would do it cheaper, not adjust the valves, and/or use lower grade replacement parts.

    Turner's neighbor and friend, Wayne Lamarre, was immediately suspicious.

    Yea, most people would be.

    "She was supposed to get a oil, lube and filter," he says. "Period. They talked her into having this done. They said the oil was going into the spark plugs, which I really find hard to believe.

    Then Mr. Lamarre has no experience working on these cars, it's a very common failure and is the #1 cause of an engine performance issue on these cars and left un-repaired will cause the destruction of the catalytic convertor.

    And that's the second set of spark plugs she's had done on that car. Why would you change spark plugs at 31,000 miles."

    Here is one of the problems with articles like this. The first reason to replace the spark plugs at 30,000 miles is because Subaru say's to, and that's if nothing goes wrong. Should anything occur that would cause a premature failure then they don't get to run that far. Preventing any misfires is important with OBDII cars, misfires put raw fuel and air into the exhaust and the catalyst will cause that to burn. The catalyst under normal operation will reach a specific operating temperature, misfires will cause the catalysts temperature to rise to the point that it will sinter, fracture, and ultimately be destroyed and then need to be replaced.

    Llewellyn says Midas uses ALLDATA, which provides information and labor estimates on vehicle repairs and diagnostics, as its guide. He also says on the day Turner visited Midas — for the first time, on the recommendation of her nephew, a longtime customer — the manager was off, replaced by a technician who priced the Impreza repairs.

    Mr. Llewellyn needs to answer why he has stores where the technicians have to cover for a manager who is absent. Especially if they aren't trained on how to do estimates correctly. Most people wouldn't look at this aspect deep enough but the technicians don't get paid for the time that they spend doing someone elses job. The get paid for the work that they get done and out the door. Putting additional burdens on them creates an atmosphere where the techs will have to rush at times just to break even and that is a routine that never ends well.

    ALLDATA, in fact, lists the sparkplug-replacement job at $63.13 for all four plugs, not each. "That's an error I have to take care of," says Llewellyn.

    Next, the valve cover gaskets — as the name suggests, gaskets under the valve covers to prevent oil leaks — that cost Turner $398.02. Llewelleyn says the technician again misinterpreted the ALLDATA guide, overcharging by $150.


    Note the word "guide". That's all it really is, it's a guide to establish an "estimate". It was never intended to be used to set actual pricing because issues can occur that can cause jobs to take longer that should not be a penalty for the technician and overlap can fail to be accounted for that take advantage of the customers. The hard part is the flat rate mentality is so engrained in the trade that I don't know how we could ever make it go away. Consider this, warranty times for this "repair" would likely pay a dealership technician about 1.5hrs to do exactly what Midas did. (not including checking/adjusting the valves)

    For Turner and anyone else getting an unexpected repair bill, especially during a first-time visit to a garage, here's another lesson: Always get a second opinion from a recommended garage.

    Yes great advice. :sick: I'll show you half a dozen shops near mine where they haven't been in a classroom in decades, rarely have a scan tool that is up to current software level, and will cut prices in a heartbeat to take work out of another shop. Adjust the valves while the valve covers are off on that Subaru? Not a chance. If you take Mr. Hunts advice you will reward the shops who aren't making the investment to keep up with the technology on the cars with your business.

    The point is you cannot judge auto repair by price alone. Articles like this aren't news if they try and explain everything, and it's likely the author has no technical experience where he would have serviced the car correctly the first time himself, let alone used the estimator system that the tech supposedly mis-used.

    BTW I met Mr Llewellyn a few years ago. His name stuck with me because that was the narrators name from the old people's court show back in the 80's. ( with judge Wapner). The biggest problem he has right now is the fact that the customer didn't know "why" this work needed done and wasn't able to relay that to her neighbor. Mistakes from people forced to do part of a job that they haven't been specifically trained for are always going to occur and need to be corrected ASAP. Sadly many businesses run on the idea that it's cheaper to fix the mistakes, than it is to train and prevent them in the first place. That BTW isn't just an auto repair issue.......
  • thecardoc3thecardoc3 Posts: 1,632
    edited December 2012
    We really should be asking you what car (or brand) to buy and which one to absolutely avoid at all costs.

    Aren't there people who get paid for such "opinions"?

    I do have a manufacturer that I buy almost all of my cars from and have never taken one back for a warranty repair. (Do not count a recall campaign in that, they are out of my control)

    There is one manufacturer for sure that I would not buy, and it has to do with repair difficulty not frequency. In fact most of my purchase reccomendations would settle around that one specific point, service-ability.

    Heck when I bought the 2002 Explorer, the first thing I did when I saw that it had running boards on it was lean down and see if they were going to interfeer with putting the car on a hoist, they didn't and so we bought it.
  • steverstever Viva Las CrucesPosts: 41,902
    Funny, the deal killer for me is whether I can get an aftermarket canoe rack to fit easily on top or not.

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