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91 model gmc 3800 v6 question

Old 07-21-2009, 06:56 PM
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Default 91 model gmc 3800 v6 question

runs fine till you shut it down hot....then it just turns over and will not start.....wait 15 to 20 minutes.....fires right back up....its not the coil pack, or the cam pos sensor....any ideas ??
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Old 07-22-2009, 11:40 AM
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anybody......
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Old 07-22-2009, 04:37 PM
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Sounds like a vapor lock. If it is carbureted, the fuel when extremely hot under the hood will turn to a gas vapor and not flow in the fuel lines. After cooling down, it will re-liquify and start. Try insulating the fuel lines or moving them away from the headers. This was common on old cars.
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Old 07-22-2009, 05:23 PM
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Yes it does sounds like vapor lock. But I thought that went away with fuel injection and even throttle body injection. Does the 91 have the old fashioned carb? I woulda said coil pack but you have put on known good coils? Ethanol blends do have higher vapor pressures and I suppose would be more prone to this...
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Old 07-22-2009, 06:38 PM
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injector leak down, it has one injector and 6 hoses that spray in the manifold. i would assume this is the vortec v6. replace the injector assembly with the hoses.
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Old 07-24-2009, 09:39 AM
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Leaking fuel pressure regulator in manifold
Replaced many of them
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Old 07-24-2009, 09:58 AM
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thanks guys....it is fuel injected....
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