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Danga16 4/6/2012
1985 Chevrolet Citation II Base 6Cyl2.8L - Engine
Why does my car stall when it warms up and then just turns over without firing?
I have a 1985 chevy citation II 2.8 V6 F.I.. When I turn the key to the on position, there is a very loud vibration under the hood. Then it has a little trouble starting but runs good for a while. Once it warms up, it tries to stall, and when it does, when I try to start it, it turns over without firing. So I'm thinking fuel or ignition. Once it cools, it runs the same exact way.
2 Answers
  • EG9 K20A3
    EG9 K20A3 4/10/2012
    There can be numerous reasons for the engine to quit running when it gets up to operating temperature.. expansion of metal parts where bolts/screws aren't tight enough, breakdown of the condenser for the ignition points (if equipped), or a possibility of a crack somewhere.

    * If the miss is a miss, the problem probably has to do with ignition or the fuel mixture. Check the tightness of the carburetor mounting bolts and where the intake manifold/air-fuel mix tube fastens to the engine block.

    * If instead, the miss is popping through the exhaust, this might be caused by a bad exhaust valve or valve seat.

    * If there is puffing or popping near the engine head, the head bolts might not be tight.

    * If the engine spins over too freely when it's hot.. indicating much lower compression, check the torque of the head bolts.. if they were loose, the engine should now restart.

    * If it won't restart until it's cooled down, the exhaust valve (and/or valve seat) may be the problem. If you can remove and disassemble the engine yourself, this isn't expensive to have corrected. If not, the shop labor for tear-down and reassembly will be fairly costly.

    If the engine is just failing to fire the spark plug when it's hot, there's a good chance that it's time to change the (points and) condenser. This can usually be confirmed by quickly removing the spark plug after it quits running, and grounding the sparkplug base securely to the engine (away from fuel vapors).. then spin the engine to see if there is a hot blue spark with an audible snap, snap noise.

    Have your fuel pressue tested, although based on your description of the noisy fuel pump (which i think is causing the noise) its about to go.
    EG9 K20A3
    Danga16 4/10/2012
    It's EFI. I checked the spark when it stopped running, but then it started up with one wire removed. So I checked the spark, it seemed a bit weak. I put the wire back on and restarted it. When it warmed up, it kept running without stalling, so I tried shutting it off and restarting it. It wouldn't start, so I checked the spark again. There was none. The pickup coil is falling apart, so I bought another one and I'm gonna install it tomorrow and see what happens. I think there is low f.p. as well.
    EG9 K20A3
    Danga16 4/10/2012
    I think the noise is the vacuum pump. The fuel pump is in the tank.
  • EG9 K20A3
    EG9 K20A3 4/12/2012
    It probably is, im online so i cant figure it out for you.

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