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A Mechanic's Life - Tales From Under the Hood

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  • thecardoc3thecardoc3 Member Posts: 5,848
    edited September 2016
    kyfdx said:

    There was still testing to do which officially was the compression test before this could be considered diagnosed but yeah I pretty much knew what was up within about fifteen seconds after first feeling the vibration that was engine speed and torque convertor clutch dependent.


    Hey! You can't just start guessing! You have to follow the diagnosis protocol! ;)

    Absolutely and that's exactly what I was doing. B) Diagnostics when done correctly work like doing theorems in mathematics. https://en.wikipedia.org/wiki/Theorem There is a marked difference between guessing and logically working through the possibilities. (aka conjecture VS hypothesis) In diagnostics, if logic can rule in/out certain possibilities that is pinpoint testing that does not have to be performed, streamlining the total effort. If a given possibility cannot be ruled in/out logically, then pinpoint testing to prove/disprove that possibility must be performed. It takes discipline to perform a lot of the necessary time consuming tests in the face of constant pressure to be fast. (faster) It's a demonstration of a complete lack of discipline and knowledge that supports the "pull a code and toss a part" repair attempts whether they are successful any given time or not.

  • steverstever Guest Posts: 52,454
    edited September 2016
    Bummer Doc.

    btw, that oil looks awful - you call that honey? ;)
  • thecardoc3thecardoc3 Member Posts: 5,848
    stever said:

    Bummer Doc.

    Yea well its just a machine doing what machines do, break whenever they darn well please.
    stever said:


    btw, that oil looks awful - you call that honey? ;)

    It still has 25% life left on it!!!

    Could have been worse actually, got a thousand miles to cover this week and twenty five hundred to do the next week. So its going to be the Mustang for the long trips and I pulled the Ranger out of the garage to fill the void locally.


  • steverstever Guest Posts: 52,454
    For those of us who drive them forever, it seems to support our "do the minimum" maintenance theory. A 3,000 mile oil change interval doesn't really matter when machines will do what machines do.

    It is nice that you were able to keep limping along and get to the clinic and then back home.
  • thecardoc3thecardoc3 Member Posts: 5,848
    stever said:

    For those of us who drive them forever, it seems to support our "do the minimum" maintenance theory. A 3,000 mile oil change interval doesn't really matter when machines will do what machines do.

    If my Escape would have been serviced like that, then the choice now would have been to scrap it, replace the engine, or do a complete rebuild instead of just pull the cylinder head for a valve job. It's often been the practice
    for someone to try and justify flawed routines based on the fact that sometimes things just happen and consumers have suffered for it.
    stever said:


    It is nice that you were able to keep limping along and get to the clinic and then back home.

    Yeah, I won't complain about that, but I was ready to park it and snag a rental car if it would have been necessary at any moment.

  • steverstever Guest Posts: 52,454
    Shifty's rule of thumb is that "modern" cars are good for about 170,000 miles.

    What's next - the AC going out?
  • thecardoc3thecardoc3 Member Posts: 5,848
    edited September 2016
    Considering the majority of cars are serviced poorly to marginally poor that's probably correct.
  • steverstever Guest Posts: 52,454
    edited September 2016
    Assuming 15,000 miles a year, that means a bit over 11 years of use.

    The way tech is going, the 600 page owner's manual you'll get with a brand new ride will have a lot of new content to learn - all the safety nanny stuff will take 100 pages and the connectivity instructions for pairing your phone and accessing your data/music on the cloud will take another 150.

    Might need a Genius to set it all up for you, but all the new goodies are a big attraction for a lot of people. And it won't take much in the way of a big repair bill to convince them to go new and dump the out of date ride.
  • thecardoc3thecardoc3 Member Posts: 5,848
    edited September 2016
    As I start setting this post up, I can't help but think about when one of the experts rotates his tires, or changes his oil and writes about it he is an automotive god.

    Here was the cranking compression test for my Escape.

    Here is the running compression test.

    That capture not only allows for proving the compression is too low, the educated eye can see the elongated intake ramp which is caused by the exhaust valve not sealing. I could do an overlay of a known good capture to help with a comparison if someone is interested.

    Here is the head removed. One of these things is not like the others.


    Close up of the burned valve.




  • steverstever Guest Posts: 52,454
    The EV fanbois say that a Tesla has about 17 moving drivetrain parts (engine and transmission). A four cylinder ICE typically has 350 or more.

    Maybe that's what's wrong with your picture....
  • roadburnerroadburner Member Posts: 18,345
    stever said:


    Might need a Genius to set it all up for you, but all the new goodies are a big attraction for a lot of people.

    That's where I come in... ;) There's no point to the technology if the client can't understand it and utilize it.

    Mine: 1995 318ti Club Sport-2020 C43-1996 Speed Triple Challenge Cup Replica
    Wife's: 2021 Sahara 4xe
    Son's: 2018 330i xDrive

  • thecardoc3thecardoc3 Member Posts: 5,848
    No there is nothing wrong with the pictures other than there isn't enough people that readily understand them.

    Well anyway, the capture above that has the overlay holds a little Easter egg. I added a highlight at the exhaust valve opening.



    The exhaust cam timing is very late. The red angled line shows where the pressure rise should be. Here was another clue.



    With the cams held in place with the locking bar, the crank holding pin needs to be installed before the crank pulley is removed. There is no keyway between the crankshaft, the crank gear, and the crank damper pulley and just removing the bolt without positioning the components can result in damage. The pin couldn't be installed, the crank is in the way. With the pulley and the cover removed, the above picture shows the pin only partially installed and the crank counterweight visible below the arrow.

    Here is the pin installed fully with the crank rotated back to TDC.



  • thecardoc3thecardoc3 Member Posts: 5,848

    Well cranking compression is testing the sealing of one cylinder. Idle compression is how the entire engine is breathing.

    A snap throttle capture would do a better job of demonstrating how the whole engine is breathing than an idle no-load capture would. With the snap throttle capture any intake restriction will make the compression peaks fail to rise high enough, which BTW is three times the running compression values. An exhaust restriction would show excessive cylinder pressures during the exhaust stroke as the exhaust system becomes pressurized.

    The reason that running compression at idle is only half of the cranking compression is because there isn't as much air in the intake manifold to charge the cylinders. The lower pressure in the intake or "intake manifold vacuum" as it is usually referred to results in lower compression readings when tested at idle. The advantage of using the pressure transducer and the digital scope is revealed in the waveforms above. The exhaust valve timing and intake valve timing ramps wouldn't show up without the pressure differentials in the intake manifold and exhaust system.

  • Mr_ShiftrightMr_Shiftright Member Posts: 64,481
    edited September 2016
    Yes, and every one of those 17 moving parts costs a bloody fortune and is readily repaired by putting them on a flatbed truck.
  • thecardoc3thecardoc3 Member Posts: 5,848

    Yes, and every one of those 17 moving parts costs a bloody fortune and is readily repaired by putting them on a flatbed truck.

    Here is a little story about a minor accident with a Tesla.
    https://cleantechnica.com/2015/01/05/model-s-owner-owing-tesla-awesome-get-accident/
  • steverstever Guest Posts: 52,454
    We have Model S values - looks like the guy's car would be worth about $56k today, clean, private party. Even more incentive to total it.
  • thecardoc3thecardoc3 Member Posts: 5,848
    So he owes $70K on it and will get $56K for it. There's going to be a lot of people limping them around wrecked.
  • steverstever Guest Posts: 52,454
    Well, he got $70k for his. Your article is a year and a half old, and maybe that's what it was worth when it was written.

  • thecardoc3thecardoc3 Member Posts: 5,848
    Too bad there aren't more details, but it is refreshing to see someone appreciating a tech getting it right in spite of the information he/she was likely given that would have started them off on the wrong foot.

    I read a post from a tech that I have quoted here in the past, I'm waiting to see if he will allow me to share it here.
    Consumers should be all over dealer management for the way that techs have been treated over the years, and this post if I get to share it goes a long way to prove why. There are some good ones of course (management) but the overall culture is still oppressive and treats techs as third world citizens. Consumers can't afford for that to continue any longer.

    BTW. Did the information about my Escape show just how complicated the work today really is? A reporter should take an unedited capture and visit shops/techs to see just how many are tooled and schooled to operate at that level and beyond. A trained technician would be able to analyze the valve timing issue, as well as the cylinder compression leak from those waveforms. Don't be surprised if the reporter goes through several hundred shops and techs before they find someone who can do what I did there. Which BTW when it comes to the electric cars, hybrids etc. the captures that I am sharing here are part of the base training that is required to work with them effectively. That technology is way beyond that compression test routine but uses the same skills and base training. You should see what I have been studying over the last two months. It makes what I share here child's play.
  • steverstever Guest Posts: 52,454
    That was a nice post by the reviewer.

    EVs may be complicated but how often will they break? The traction batteries should be good for ten to fifteen years. Electrical stuff breaks but often if you have a bad component or faulty wiring, that'll show up early (which is why you should immediately take whatever new gizmo you've purchased out of the box and "burn it in").

    Even the normal wear of the brakes will be less and there's fewer fluids to change.
  • thecardoc3thecardoc3 Member Posts: 5,848
    edited September 2016
    All of the systems use DC to AC invertors, motors and batteries that have to be cooled. They all use some type of hall effect sensors to report motor armature position so the motor control module knows which circuit to apply power to and when. The most troubling part is when a problem occurs, failures can be detected in a few thousandths of a second. Failures result in limp in strategies being implemented (think stabilitrack) where the only way to prove an intermittent failure is to have solid electronics, scope and scan tool skills where one can predict what the failure might be and then customize testing to prove or disprove if that is correct or not.

    REM. Trouble trees are useless for an intermittent failure, they ONLY work when there is a hard failure that is current at the time that testing is being performed. Now imagine having to do that for any and all systems on the car and not just the power train. There is a reason why salvage Tesla's don't sell very well at less than 20% of the original price. https://www.salvageautosauction.com/make_by/Salvage-Tesla-for-Sale
  • steverstever Guest Posts: 52,454
    edited September 2016
    Heh, almost be worth taking a flyer on one, but something tells me that they wouldn't accept my $425 bid for that silver 2013 Model S.

    But maybe they would - estimated repair cost is $52,824.

    Sounds like a business op for you Doc. ;)
  • Mr_ShiftrightMr_Shiftright Member Posts: 64,481
    edited September 2016
    stever said:

    That was a nice post by the reviewer.

    EVs may be complicated but how often will they break? The traction batteries should be good for ten to fifteen years. Electrical stuff breaks but often if you have a bad component or faulty wiring, that'll show up early (which is why you should immediately take whatever new gizmo you've purchased out of the box and "burn it in").

    Even the normal wear of the brakes will be less and there's fewer fluids to change.

    Judging from Consumer Reports survey analysis of Tesla owners, EVs break *A LOT*.

    It's really not the frequency of EV breakdowns, but the fact that when they do break, neither DIY or local shops are going to handle most operations. So, EV = lengthy downtime.
  • steverstever Guest Posts: 52,454
    Lengthy downtime? Like trying to get a recalled air bag replaced? Nothing new with slow repair work.

    Something tells me the Prius Plug-In isn't going to generate the warranty claims that the new kid on the block will. The Bolt probably won't either.
  • Mr_ShiftrightMr_Shiftright Member Posts: 64,481
    edited September 2016
    You're talking an extreme cases. I'm talking about any EV that breaks down. You're going on a flatbed to a specialist and if something has "cooked", you're going to have considerable downtime and a long drive home.

    THIS, from Green Car Reports: (sorry for the illiteracy but that's how they wrote it)

    "People who purchase electric vehicles and other green cars are usually interested in keeping their cost of driving low. What should be known by these people is the fact that green car repair and service can be significantly more costly than the cost of typical car maintenance. Technology in Electric Vehicles is New Electric vehicles are not really that new anymore but the technology used in these vehicles is considerably different from that of the other cars that came before these green cars. Because of this, the price of repairing a green car is higher in terms of both parts and labor than what you would find the cost to be in a car that implements older technology."
  • steverstever Guest Posts: 52,454
    edited September 2016
    lol, you're talking to a guy who had a bad distributor in Port Huron that took three days to finally get it correctly diagnosed and fixed, and that required a 40 mile tow to the Nissan dealer in Detroit. Three different shops looked at it before the dealer.
  • Mr_ShiftrightMr_Shiftright Member Posts: 64,481
    Yeah, but Doc knows why you had your downtime, and it wasn't the fault of the car's technology.

    If your car was a Nissan Leaf and you brought it to Doc with some fried drivetrain components, he's going to send you elsewhere I bet.
  • steverstever Guest Posts: 52,454
    Either way, I'm not dropping my towing insurance. :)
  • thecardoc3thecardoc3 Member Posts: 5,848
    Not so much send him elsewhere, I'm not likely to be in the shop for him to even have a chance to have me try. Could I handle it? Actually I can. But would it make sense for me to bother, that's the real question. If I could determine that I would be able to collect data for a training class, on top of fixing it, then it would be worth what ever time it required. Otherwise it would be little more than a goodwill gesture.
  • thecardoc3thecardoc3 Member Posts: 5,848
    edited September 2016
    You may recall a Chrysler Town and County mini van I posted about a month ago. The short story was the guy had already done a bunch of repairs trying to solve a transmission issue including replacing the PCM for a P0605 which was the right code but he replaced the wrong module. He needed the TCM, not the PCM.

    After proving the powers and grounds, the only thing left to do is replace the module for that code and be balked at the estimate that he was given. He paid for the diagnostics up to that point and took his car. Well, guess what happened, he bought a TCM online and installed himself and he still is having trouble. He called me up and wanted to know what I was going to do about it. He took me out of the loop by not having me do the repair with a part sourced from a supplier that I could not use. l not only can stand behind my supplier they would also stand behind me. If he had bought it through me and we ended up here, then my routine would include additional diagnostics to prove what is going on, and that would be done N/C. That's just the risk that we automatically embrace when in business. If I prove the new part is defective, then that's between me and the supplier. If I prove that there is another issue on the car that caused a now functioning module to shut the system down then we would simply advise him from there. Some people might not be aware of this but the progressive nature of today's computer controls means that once certain codes set, no other tests run and that means if someone cleared codes before we get to see the car there will be only the primary codes set and no evidence of any other failure to work out.

    So what could I do for him now? I asked him what code was setting, and he didn't know and cannot pull codes himself. So we don't know if its a new problem, or the same problem. We don't know if its internal or external of the PCM that he bought from someone else. I explained to him the routine right now is to forget everything you know about what has been done to the car, and start the testing from the beginning. That is all that I can do if he brings it back in, and the only thing that I can tell him to do if he doesn't.

    By bringing his car in for the diagnostics, and refusing the repair he stood to save himself a lot of money that amounted to me earning less than I really should have for the effort that I put forth. If everything would have gone smoothly, he would have won the day. Now he is right back a square #1 and I don't know if I really want to do anything else for him.
  • Mr_ShiftrightMr_Shiftright Member Posts: 64,481
    Well you don't owe him anything, so I'd say ball's in his court there.
  • thecardoc3thecardoc3 Member Posts: 5,848
    A very expensive oops. A customer called about a 1999 F250 Super Duty that had the brakes dragging. There had already been several attempts to resolve the condition including replace the master cylinder three times and the hydroboost at least twice. The first thing I asked the customer was if anyone had mentioned contaminated brake fluid and if that was a possibility and he was not aware of such information. I asked him to inspect the master cylinder cap seal to see if it was swollen and stated that it was not.

    Upon getting the truck I found the master cylinder had washers installed between it and the booster effectively shimming it out from is normal seated position. The pushrods in a hydroboost system are not adjustable like a lot of booster systems, so this was a very odd finding. Upon inspecting the truck, both rear and the right front calipers were dragging from pistons sticking in the bores. The left front was dragging but releasing the pressure by opening the bleeder released the wheel. That means something was wrong upstream keeping pressure on the brakes. The right front brake hose had an obvious fluid blister indicating a leak in the innermost layers.
    With the master cylinder being new, and not completely full the possibility of the fluid being contaminated at that point could not be ruled in or out, however pulling it from the booster and removing the washers that should not have been there confirmed that the master cylinder was incorrect for the system. The correct new master cylinder fit flush with the booster when set into place.

    We finally got the OK to repair the truck and yesterday when I pulled the reservoir off of the old "new" master cylinder in order to install it onto the new correct one I found this.



    Now I have proof of what has been going on and get to completely flush the lines as part of this repair.
  • steverstever Guest Posts: 52,454
    Was that the original fluid too, do you think?

    And had another shop done this work or was it a D-I-Y deal?

    Really makes you want to get out on the streets and highways with this kind of stuff out there. And why didn't the PA car inspection catch this?
  • guitarzanguitarzan Member Posts: 873
    edited September 2016
    It appears like oil and water. Does old fluid separate like that?
  • thecardoc3thecardoc3 Member Posts: 5,848
    edited September 2016
    stever said:

    Was that the original fluid too, do you think?

    With as many times as the master cylinder was changed, it was likely a combination of new and old fluid.
    stever said:


    And had another shop done this work or was it a D-I-Y deal?

    Back Yard Joe and DIY combined.
    stever said:


    Really makes you want to get out on the streets and highways with this kind of stuff out there. And why didn't the PA car inspection catch this?

    This was last inspected in January, the trouble started early this past summer. The only history the owner mentioned that might be relevant is a relative had borrowed the truck and a brake line had failed and was repaired while the relative had it. A couple months later the locking brakes symptom occurred.

    As far as state inspection catching something like this isn't your usual perspective that you want to complain when the shop DOES find something?

  • thecardoc3thecardoc3 Member Posts: 5,848
    guitarzan said:

    It appears like oil and water. Does old fluid separate like that?

    Brake fluid is hydroscopic, meaning it absorbs water which serves to prevent it getting concentrated at any one point, which BTW would usually be the lowest points in the system such as the wheel cylinders and calipers. Water in those components would boil from the normal heat generated during braking and result in a pedal that goes straight to the floor the next time that the brakes were applied. So what ever it is, it isn't water and it is attacking the rubber seals in the system. While the master cylinder cap seal wasn't distorted, it is newer and the fluid wasn't high enough to come into contact with it preventing that usual way to detect contamination. However, the reservoir seals were clearly distorted having absorbed some of what-ever that fluid is. The same would have happened to the new master cylinder piston seals and bypass and relief valves. It also damages the hoses and the caliper seals.
  • Mr_ShiftrightMr_Shiftright Member Posts: 64,481
    What would happen if you mixed DOT4 and DOT 5?
  • steverstever Guest Posts: 52,454
    So the annual inspection didn't do any good in this case. Need to make them quarterly. :D
  • thecardoc3thecardoc3 Member Posts: 5,848
    stever said:

    So the annual inspection didn't do any good in this case. Need to make them quarterly. :D

    So your advocating for a three month service?
  • steverstever Guest Posts: 52,454
    Well, that would miss those brake problems that happen at the two month interval. Better make it weekly.
  • roadburnerroadburner Member Posts: 18,345
    DOT5 is a PITA except for specific situations.. DOT4 is my choice

    Mine: 1995 318ti Club Sport-2020 C43-1996 Speed Triple Challenge Cup Replica
    Wife's: 2021 Sahara 4xe
    Son's: 2018 330i xDrive

  • thecardoc3thecardoc3 Member Posts: 5,848
    DOT 5.1 is the best of both worlds and fast becoming the preferred specification among a number of O.E's.
  • thecardoc3thecardoc3 Member Posts: 5,848
    stever said:

    Well, that would miss those brake problems that happen at the two month interval. Better make it weekly.

    How about we leave decisions like that up to people who actually know how to service and repair the vehicles? That would be better than having someone with no experience simply waffling every time something doesn't work out in their favor.
  • steverstever Guest Posts: 52,454
    Because we consumers don't trust those people?

    Nightmare at service, beware Of state inspections
  • thecardoc3thecardoc3 Member Posts: 5,848
    stever said:

    Because we consumers don't trust those people?

    Nightmare at service, beware Of state inspections

    I am a automotive instructor and teach pa state inspections. To day I toke my prius in to get inspected. I was told that I had a part that was bad and would not pass. I drove the car home believing the inspector. I placed the vehicle on my lift and performed an inspection or part. It was not bad, I drive back to the dealer and ask to be shown the bad part. I was shown after waiting 1 hour the part. There is a part on each side of the car and bolts react the same, however the tech says only one is bad? PLEASE be aware of this dealer,they like to fix anything.... the owner talked to me and had zero concern for my side of the story and was not customer service orianted.

    He's an automotive instructor and teaches State Inspection? The school would have a working shop and their own stickers, why wouldn't this person just run the car through his own shop? I can easily swing by there and check out the car and the rest of the details but I suspect the writer would want no part of that. "If" he really is an instructor and this is a sample of his work that goes a long way towards explaining why some schools aren't even close to preparing the kids for the challenges of a career as an auto technician.
  • thecardoc3thecardoc3 Member Posts: 5,848
    BTW. What is this smart_tag.js stuff from mono.vizu.com stuff that keeps showing up here?
  • steverstever Guest Posts: 52,454

    BTW. What is this smart_tag.js stuff from mono.vizu.com stuff that keeps showing up here?

    Second report I've seen, thought it was a one-off. I think it's some tracking software you picked up elsewhere that's following you around. There's a link in this post that may help.
  • steverstever Guest Posts: 52,454

    stever said:

    Because we consumers don't trust those people?

    Nightmare at service, beware Of state inspections

    I am a automotive instructor and teach pa state inspections. To day I toke my prius in to get inspected. I was told that I had a part that was bad and would not pass. I drove the car home believing the inspector. I placed the vehicle on my lift and performed an inspection or part. It was not bad, I drive back to the dealer and ask to be shown the bad part. I was shown after waiting 1 hour the part. There is a part on each side of the car and bolts react the same, however the tech says only one is bad? PLEASE be aware of this dealer,they like to fix anything.... the owner talked to me and had zero concern for my side of the story and was not customer service orianted.

    He's an automotive instructor and teaches State Inspection?
    His email checked out when I looked. And yeah, not encouraging from several points of view.
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