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  1. #1

    Default 89 c2500 Help!!!

    I just got an 89 C2500 for free and I am having some issues with it. Please bear with me as this is my 1st GM vehicle. I have been a die hard blue oval guy for years. Anyway, so here's the scoop. Got the truck knowing it had sat for over a year and needed a tranny. Here are the events that followed so please weigh in. Even if it's to bust my balls for being a Ford guy!! haaa....


    89 C2500
    5.7 Auto
    700R4 trans

    Series of events:

    1.Got the truck
    2. Got it running and it ran great
    3. Realized the exhaust was slappy so I replaced it. Cut off the cat and the muffler. Replaced everything but the cat.
    4. Replaced the trans.
    5. Realized I had a hung caliper on the driver's side and replaced both calipers.
    6. Test drove the truck and it ran great!!
    7. Brought the truck home and let it idle in my driveway so I could clean up my tools
    8. The truck just slowly dies.

    I have tried to start the truck and it acts like it wants to start but runs like crap!

    Here's what I've done so far.

    1. Checked the fuel pump and the filter. Both good.
    2. The TB is getting fuel.
    3. Replaced the IAC and the coil. No change.
    4. Replaced the MAP sensor. No change.
    5. If I remove the hose from the MAP sensor and plug it, it acts like it wants to run but runs really rich and if you try to give it gas it just stumbles and really wants to die.

    I am lost on this thing. Any ideas?


  2. #2


    A couple things to check. You didn't detail what you did with the fuel. It's very possible the old fuel has messed up the injectors. Do you see them spraying? Both should spray the same. One or both could be stuck open leaking excess fuel, or gummed up and not spraying well. Another possibility, though I doubt it if it's cranking OK, is the alternator or battery connections. What's the voltage with the engine running?

    I won't give you much grief yet, just glad you left the dark side
    When you hear hoofbeats, look for horses not zebras.

  3. #3


    I just put about 8 gallons of new gas a can of Seafoam.


  4. #4


    Quote Originally Posted by Superlead76 View Post
    I just put about 8 gallons of new gas a can of Seafoam.

    Before or after the problem started? Did you get rid of the old gas first?

  5. #5


    I didn't drain the old gas. I just added new gas to it. It's just really weird because the truck was running killer.

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