Any GM mechanics out there?

Discussion in 'Wheels, Wings, Mud, and Water' started by HiFi in WYO, Nov 11, 2017.

  1. dosmalo

    dosmalo T-Totaled Subscriber

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    I apologize for sounding as if I was throwing cold water.
    I recently had my 1st encounter with dealership service and even though I got out of it for a little over a C-note ( :confused: I know, unbelievable huh?) it was not what I would call a very tasty experience and I drove away and back home like I had stolen my own car.
    And, although not a driveability problem, still with a problem nonetheless.
    Having fingers crossed to you having much better luck and a better experience! :thumbsup:
     
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  2. gadget73

    gadget73 junk junkie Subscriber

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    This might sound odd, but its possible this thing is too old for people at the dealership to understand. Hopefully you get someone who has been there a while and knows how to work on these. GM quit making this engine setup what, 15 years ago now?

    and yeah, I missed the mention of LT1, but its a 350, not an LT1. That engine went into Corvettes, Impalas and Caprice 9C1 police cars. The goofy OptiSpark distributor behind the water pump is the dead giveaway for that one. If its at the back of the motor its just a regular old 350. The "Vortec" thing is just the heads. They made them with carb intakes too, a fair number of marine engines in the late 90s through the mid 2000s ran them.
     
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  3. whoaru99

    whoaru99 Epic Member

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    As long as it easily exhibits the symptoms (you are going to demonstrate, not just describe, the problem to them, yes?) there is a fair chance.

    If it is intermittent, then, good luck...unfortunately you'll probably need it because they can't fix what ain't broke at the time unless you allow them to throw parts at it with crossed fingers.
     
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  4. HiFi in WYO

    HiFi in WYO The universe is a big place, perhaps the biggest. Subscriber

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    Yeah, it's the old, regular 350. And I'm not sure if it's the same cylinder misfiring - there's no codes anymore.

    I have managed to get it into my more regular mechanic today. They'll do all the scans, tests to see what's going on. We shall see. I'm going to bet on the distributor being worn out. Those flat-top distributors have a history of wearing out - although at 150,000 miles, anything that I haven't already changed could be bad or dying. I had also thought about the ECM - I've run into bad computers before, so this wouldn't surprise me either. They will look into that as well.

    dosmolo - no worries. I'm just enough of a gearhead to be somewhat knowledgeable and dangerous ;) I'm no expert by any means, but I have been wrenching on vehicles for about 35 years - mostly out of necessity ($$$). My rationale is it's just a big collection of parts and no matter if I pay someone or do it myself, it's the same job, though it does tend to take me longer.

    gadget73 - I think you're right. Newer vehicles, though harder to work on (try a twin cam Hyundai 3.5 V6 - christ, what a PIA) tell you what's wrong with them and I think that in a way, mechanics lose that instinct and feel for what's wrong. I've been around mechanics much of my life - there was an art to listening to an engine and narrowing down a diagnosis. I think a lot of that has disappeared. I'm much more old school. I listen to the engine and let it tell me what's going on. However, I know my limits and know when I'm whooped. In this case, so far, I'm whooped!
     
  5. gadget73

    gadget73 junk junkie Subscriber

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    I have stuff with older EFI as well, and its almost as much art as science. The ECM is really limited, whats in your truck seems like a supercomputer compared to what my 80s Fords can tell me. I've seen more than one person give up because the ECM wasn't smart enough to tell what was wrong with it.
     
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  6. Shadowdog

    Shadowdog Super Member

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    So it has the distributor at the rear just like all SB Chev?
     
  7. beat_truck

    beat_truck Super Member

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    Yes.
     
  8. Shadowdog

    Shadowdog Super Member

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    That's what I figured, so easy to fix if needed there! I doubt if if the dist bushing would be worn out, but I guess it could happen. They can be lubed though and easily checked for play. It won't have any advance timing wts. either as the electronics take care of that .

    Timing chain might be an issue with 150K miles though as the chain can stretch & start jumping.
     
  9. HiFi in WYO

    HiFi in WYO The universe is a big place, perhaps the biggest. Subscriber

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    ... and the winner is: mkane! Though it wasn't the bushings.

    They hooked it up to the big machine and found out it the timing was off. Removed the distributor and the gear was worn just enough to throw the timing off. So new distributor, reprogram the timing and it seems to run as new (it should - everything else is new).

    It looked like it was worn thinner, not shaved down. The oil pressure is fine, so I think it's just wear over time, not something indicative of a more serious problem.

    Thanks for all your help!
     
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  10. dosmalo

    dosmalo T-Totaled Subscriber

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    Great! Sounds like a happy ending!
     
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  11. Shadowdog

    Shadowdog Super Member

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    Could have just replaced the gear as usually the distributor lasts much longer before it's bushings go. Timing chain replacement might be good idea soon as it can leave you stuck or cause more damage in rare cases.
     
  12. gadget73

    gadget73 junk junkie Subscriber

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    Must have been worn pretty thin. Was the timing dancing around from the slop, or did it really just need the distributor tweaked to put it back in time? I know there is some goofy procedure to time these things involving the ECM tuning mode. Not quite like the old days where you just pulled the plug to disable ECM timing control and set it with a light.
     

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