Question 1987 GMC V2500 Sierra Classic Code 44 Lean Fix?

Discussion in 'Classic GM' started by Earl Phillips, May 18, 2017.

  1. Earl Phillips

    Earl Phillips New Member

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    This truck just had the motor replaced with new GM crate motor 5.7ltr in OCT2016. As a note: the idle surging problem existed prior to this writing and I had replaced numerous parts to no avail. Garages told my problem prior to replacing motor was an either a internal vacuum leak and needed to replace my intake manifold gaskets or water pump etc. None of those repairs helped. Since a bearing went on the bottom end and the motor needed to be replaced, I thought this would solve my issue with surging idle. After three weeks at a dealer, checking and or replacing numerous parts they determined they could not fix it. They turned up the idle screw and gave up. In my effort to help myself, I replaced the vacuum booster but that did not make a difference in the idle fluctuations. In 6 months I have 700 miles on the new motor and recently I notice a momentarily hesitation and then the check engine light came on. Code 34 & 44. Dealer told me to check for a vacuum leak. I did look and could not find any cracked hoses or lines that are not connected. I plugged the vacuum line that even feeds the vacuum pots for the heater controls, nothing changed. Looking for suggestions that could possible be the culprit other than the obvious ie: IAC, TPS, TBI & gaskets, Injectors, EGR, MAP sensor, Charcoal Canisters, Vacuum Booster, fuel pressure, fuel tanks, fuel pumps, dry or brittle vacuum lines, vacuum ball reservoir. Thanks...
     
  2. Art61

    Art61 New Member

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    I would recheck the airgap for the idle and find a procedure for Iac reset just in case they missed something i'm not sure what year your truck is I'm hoping it's in the 90s
     
  3. Art61

    Art61 New Member

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  4. Art61

    Art61 New Member

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  5. Art61

    Art61 New Member

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  6. Art61

    Art61 New Member

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  7. Art61

    Art61 New Member

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  8. Art61

    Art61 New Member

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  9. Art61

    Art61 New Member

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  10. Earl Phillips

    Earl Phillips New Member

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    The truck is a 1987 v2500 Sierra Classic, 5.7 ltr TBI. I checked the truck today and the only code it is show is 12 and 44. I just don't know where else to look for a vacuum leak. When it was at the dealership they had tested fuel pressure was within the limits.
     
  11. Art61

    Art61 New Member

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    Code 12 the system OK they all start that , it's a system check mine does it too I feel for you I have a brand-new crate engine too 3 Gm mechanics can't figure out the problem I would check for exhaust leaks and the O2 sensor according to the book
    Good luck
     
  12. Art61

    Art61 New Member

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    You pretty much need a OBD one scanner to work on these things like a tech one or a tech two or a snap on
     
  13. Earl Phillips

    Earl Phillips New Member

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    Thanks Art... I printed out those pages, thank you. I would have thought the Chevy Dealerships mechanics would have performed these procedures at that time. As a novice in comparison to the combined mechanical abilities and knowledge base of the certified mechanics, I am to say the least a bit flabbergasted. Thanks again...
     

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