1989 chevy 350 tbi starting problem

I have a 1989 chevy 350 tbi that will not start when hot. I have changed the cap, rotor, throttle body, ignition module, egr valve, plugs, wires, checked fule pump, and filter. I have checked the
pickup coil, it is 834 ohms. I can dump gas down the intake and it still will not start. I have spark, but it seems like it is advanced or retarded. Does anybody know where to go next? What controls the spark timing? It does not have a vacuum advance. The truck starts when cold, runs fine, then when I shut if off, it will not start. It has to sit for 5 to 8 hours before it will start again. If anybody can help me I would greatly appreciate it.
Thanks, Jon
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at my friends repair place they just had one that acted the same way the timming was off a little and the temp. sensor was bad so the computer thought it was cold all the time which would dump a lot of gas in. the computer advances or retards the timing. if i remember wright there should be two sensors one is for the temp gauge and one for the computer to tell it when it is up to normal temp. the one on the side of the motor by the manifolds it is for the gauge the one on top that is screwed in the intake is the one that u want to replace hope this helps
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I planned on replacing that next, but we just had a blizzard and I have no garage. I hate working on things in the snow. From my understanding now, the coolant temp sensor controls fuel when cold and the oxygen sensor controls it when hot. Hopefully I have time to swap out the sensor over the holiday. Thanks rick.
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the coolant temp controls it when it is cold and hot when it is cold it tells the comp. to adjust the timing and to spray a set amount of fuel in. when the thing is hot the temp.sensor tells the comp. to adjust timing again and then the oxygen sensor takes over by going into a rich-lean mode it switches back and forth very fast if you had a scanner you would see it going from rich-lean also when you are going to replace it have one with you i dont know how much coolant you will lose so when you pull it out have the other one in hand to switch it fast to save your coolant. also have your timing checked with a scanner it is a lot more accurate
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Thanks Rick, it was the coolant sensor. Runs and starts fine. Now I can plow this white crap that keeps falling out of the sky.
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double check spark,make sure you have good spark at the plugs
are the plugs wet when the truck won't start? if so dumping gas down the throttle body will just compound the problem.
are the injectors firing when it doesn't want to run? if not check power and ground to them (ground is pcm controlled) make sure all the regulars are good,commpression,vacuum,timing,fuel pressure
if you think that it is flooding unplug the injectors and crank the engine over fo 30 seconds or so to clear the fuel out of it. then plug back in and retry to start. test these things and repost
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