'87 Chevy Stalling...

Discussion in 'Chevy Truck Forum' started by 87ChevyMan, Jun 10, 2010.

  1. 87ChevyMan

    87ChevyMan Full Member

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    I've got an '87 chevy truck, 5.7L TBI, 700R4. It has pretty low mileage on it, only 57k. I've noticed that when I'm idling and I shift gears, such as P to D or P to R, it tends to stall on me. Having the steering wheel turned exacerbates the problem also. The truck seems to do fine at highway speeds, it's only at idle speed. I've asked around on a few diagnostic websites and have heard all sorts of things from "It's your IAC sensor" to "Its your fuel pump..." Has anyone else encountered this problem before on the same or similar truck? Your insight is appreciated.

    -JWR
     
  2. crabtruck

    crabtruck Senior Member

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    Welcome to the forum 87ChevyMan.

    I copied some of the details you had in the other posts over here
    so folks could see all of it at once, all the details gives better chance.
    Sounds to me like you may have a vacuum leak. See what the smart guys say...

     
  3. Oldmech

    Oldmech Full Member

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    gah.... take the dist cap off and look in the dist.. see if there is any oil in the base.. GM had a problem, and a recall on those, the cure, was to put a spiral groove in the shaft to force the oil back down when the dist turned... pretty uncool imho.. but i did replace a LOT of them.. and the fix seemed to work. I would have been much happier with a better seal..... the stock dist as came from the factory was letting oil up into the dist, it made a mess and gave some VERY wierd running problems.
    Another thing to check is your IAC pintle.. being an 87, it might be getting worn where it slides in and out, letting the pintle hang down a bit, so it binds when it tries to close, and is basically a vac leak. if you unscrew the IAC you can see the normal wear ring where it seats, but on the bottom there will be a larger wear patter where its been scrubbing trying to lift itself vack up into position..
    The base gasket for the tbi on those was also known to "suck" in also creating a vac leak...
    just a few things to check, let us know what you find!
     
  4. 87ChevyMan

    87ChevyMan Full Member

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    I'll check the distributor like you said. Now that I think of it, the truck did seem to have some hesitation if I mash the petal to the floor from the get go. So connecting the dots...stalling, oscillating idle, strong gas smell (unburned fuel), and hesitation--could all be because of gunked-up distributor. As for the IAC, I just replaced this sensor (no difference), so I doubt the pintle binding would be the issue.
     
  5. Case 7230

    Case 7230 Senior Member

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    Is there any difference in the way it runs between the engine cold and hot?
    Have you checked the fuel pressure? Have you checked for any trouble codes?
     
  6. 87ChevyMan

    87ChevyMan Full Member

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    I have not checked for any trouble codes, and the engine doesn't seem to run differently at idle, vs. cold. The one thing that is different is that the idle is "higher" when its cold, but that's normal. Once the engine is warm, the idle settles down to around 900 rpms or so. I mean, if I crank the truck and its idling 1200-1500, I can put it in reverse and it more than likely won't stall, but thats not to say that its a "warm" vs. "cold" issue; its more a matter of rpm. If you put a load on an engine (such as power steering, shifting into gear...) its going to bog down the motor--its just a matter of whether or not the engine can compensate by increasing rpms. I could always just permanently increase the idle a few hundred rms, and then it would probably "fix" it. But I really don't like the idea of rigging the throttle to keep from stalling.
     
  7. Oldmech

    Oldmech Full Member

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    There is an idle screw on the tbi. Its under a little metal cap on the drivers side... but you really shouldnt need to fuss with it... unless someone has removed that cap and already fussed with it????
     

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