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Help with a S10 pickup problem

Discussion in 'Off Topic Threads' started by sliverbulletexpress, Oct 17, 2011.

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  1. sliverbulletexpress

    sliverbulletexpress TS Member

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    Been trying to help a neighbor with his old pick up. He's paid for a fuel pump, plugs, fuel filter, new catalytic converter, and all to be put in but he still has a hesitation problem. He's about run out of money so I'm trying to help him. It's a 1988 Chevy S10 with the 4 cyl and manual tranny. It runs fine except right off idle it will just lay down unless you keep the rpm up a lot more than you should. It's got the throttle body fuel injection, I used to mechanic some but don't know much about throttle body. If it was a carburetor it would be like the accelerator pump quit working. Any help would be appreciated.
     
  2. Bruce Specht

    Bruce Specht Well-Known Member

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    If you can find a timming light( Old School)set it as if you were checking the timming. Aim the beam at the bottom of the injector and let the truck idle. You should see a very fine spray and not drops of fuel. If you see drops the injector needs to be rebuilt / cleaned it may be getting to much fuel. Common on older GM's with TBI systems.
     
  3. sliverbulletexpress

    sliverbulletexpress TS Member

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    Thanks for the tip I think I have an old timing light somewhere. If I was guessing I would guess it was lean but if it's not atomizing the fuel I can see where it would do that. Supposedly the place that did all the other work " graphed" all the modules or whatever and they were ok. somethings not right for sure.
     
  4. sliverbulletexpress

    sliverbulletexpress TS Member

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  5. K-GUNS

    K-GUNS Member

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    If its got high milage it may be gunked up under the throttle body,common problem
     
  6. todd farris

    todd farris TS Member

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    You might remove the idle air control and make sure it is clean. As well, it could be a slow reacting IAC.

    Todd
     
  7. birdtracker

    birdtracker Active Member

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    I am feeling distributor on this one. Since you have to keep the rpms up you are keeping the advance up. When its at idle and stumbles the advance could be slow. The truck probably has over 100,000 miles on it. I am guessing distributor.Maybe bushing is worn. Just my mental telephy working tonight. But its really strong. Birdtracker
     
  8. grntitan

    grntitan Well-Known Member

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    Clean the throttle body with carb cleaner. I bet it will purr like a kitten afterwards. As mentioned above, the TB is likely gunked up.
     
  9. short shucker

    short shucker TS Member

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    I would also check and see if a piece of carbon has fouled the EGR valve. I had this happen and it caused me all sorts of fits.

    ss
     
  10. Auctioneer

    Auctioneer Well-Known Member

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    I have a Ford truck with a straight 6 engine. It to had a miss in the engine. I had replace the distributor the past winter. I found that the cap had screws bolts to hold the cap on and the holes for them had not only stripped but also inlarged. The bolts were fine but wouldn't hold. I had to put nuts on them to hold the cap in place. It worked and no miss.

    With another engine it was a crack in the cap. Check also the rotor button. I have had a bad rotor button before.

    In a VW I have had in the cap the center button the button had just fallen out.

    I would look at spark plug wires, plugs, cap, rotor button, Distributor its self.

    Someone above said to get a timing light. Use the timing light on each of the wires. That way you can see what wires are not firing and or not firing all the time.
     
  11. Hemlock

    Hemlock Member

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    Just had the same problem with my daughter's S10. Checked the MAP sensor first and it was OK. Replaced the EGR valve and it ran like a new machine.
     
  12. trim tab

    trim tab Active Member

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    Check EGR operation, could be opening to soon, check idle air passage make sure its not blocked with carbon.
     
  13. kiot98

    kiot98 TS Member

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    If you feel it would be an accelerator pump(if it was carbed), check the throttle position sensor. It replaces the accel pump. You can ohm it out while opening the accelerator. It should be a steady increase or decrease in ohms. An egr should cause an idle problem if it is open.
     
  14. Remstar311

    Remstar311 Member

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    My 2001 s10 had intermittent problems with the throttle position sensor. It would idle, but when trying to take off it would cut out. Had to really feather the gas and get lucky. Not skip, but run like you are coasting down a hill in gear with the engine off.

    Might also be a vacuum line.
     
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