1995 Caprice, cranks, but won't start when hot

[rhandwor]

A computer ground blk/wht is connected to front of left cyl head. Fuel pump ground left rear wheel in engine compartment. Both front & rear wheel house must be a misprint. Check both until located.Base of left A pillar behind kick panel. Rear of right cylinder below exhaust manifold.
You should have a pressure regulator around the rail with a vacuum hose on it if it leaks gas when pulled it is bad. You can pinch off the return line in a rubber hose section with vise grips. Use a 12 volt test light on the coil neg. will it blink check cold and hot. If the computer loses a ground it will shut down. On the black & white on the module check blk/wht wire to the ground touch the wire at module and touch a ground.
Go out in the morning and heat the module with a hair dryer if it won't start get it replaced. I had a friends car I was checking out and as I have a module tester I asked him to get me one. He brought 3 PDQ modules in a row that were bad new ones. As he had had a kem I told him to insist that parts man to replace it with another kem. It was good.
Was the computer prom replaced or just the computer.

[jdl]

I like to check all the circuits. I realize it may lead back to the same problem. But, there is no ignition control because, there is no low resolution signal, because? Are you losing ignition feed to the distributor? Red wire terminal c. There might be issues involved with trying an alternative source for the ignition feed, maybe not.

If you try adding feed to the ignition circuit, I would disconnect the ecm end.

[astra1]

I bought a fuel injection pressure tester to eliminate the fuel system. Pressure is fine when cold or hot, pressure regulator also works fine.So the fuel system, including all grounds for the fuel system is eliminated.Will any of the hand held engine diagnostic computers diagnose an OBD 1 system while running to detect if the optical sensor, or one othe supporting chips are opening up on the rebuilt distributor that I put in. Will it aso check all the sensors? Did I tell you the car seems to be overheating, at least that is what the gage is saying. The thermostat has just been replaced. The radiator is not very warm at all. Water is comming out of the cap when hot, and the cap is not that old. The fans work when the radiator gets to the proper temperature. This car is the worst piece of junk I have ever owned. It is a true lemmon, or maybe just a bad year. Both my Dodge Caravans, my Ford Probe, and my Toyota Corrola opperate fine. My 89 Caprice that I had previous to this car was a 1000 times beter car. If this is the kind of junk GM insists on puting out, I won't own another GM. I guess land fills are good for something.

[rhandwor]

I would pull the water pump and see if the impeller is spinning on the shaft or fell off. Stick a water hose in the thermostat housing remove lower hose and flush out the system.
Before doing this I would run the car until it trips off. Immediately pull the distributor cap. Then I would feel the optical sensor. After it cools down I would use a heat gun like a pistol type hair dryer or lineoleum heat gun,and heat up the optical sensor until it feels the same as when it shut down. I would then install the distributor cap and see if it will start.
If your engine got hot enough on top to get the sensor to 212 deg. it most probably took out your unit.
I never used the new gensis enough to know what it can completely do.
I don't think my otc 4000e will say what is causing the problem but you can monitor the system. Most parts stores will warranty a defective part. The GM dealer may have a tester for the dist. sensor call and ask. If they sold it to you and they can do this insist. But it will have to be at shutdown temperature.
Even using a module tester you have to heat it up before it will fail. This is why I suggested to try it in the car.
I ohmed my mazda wiring more than once and never could find a problem but I used a new piece of two wire shielded cable and it run perfectly. You have to ground the shield. If your losing signal it has to be a computer,optical sensor or wiring. My car would run properly for 30 min shake then run properly and shake again but never shut off.
This is why I think your optical sensor is bad. Computers don't normally heat up and fail. Especially two even if from a junk yard.

[jdl]

You never did say if you were losing ignition feed to the distributor? The low resolution and high resolution signals are digital signals. If you have a dmm with tach--dwell--frequency signal, any of these will react to those signals. A digital logic probe should react to a pulse on those circuits. If the pump runs and you have ref voltage to sensors while cranking, the computer isn't shutting down, at least not on those circuits.

[fubar1420]

Even though this is an old post i just came across it. My best educated guess would be . water temp sensor. tok me forever to figure it out on my trans am. after replacing damn near everything down to the timing chain. it ended up being a $5 sensor