91 Lumina APV dies after 15 minutes

I would say it's related to one of 2 things:

1. Heat.
2. Going into closed loop, although it should be in closed loop long before 15 minutes, so this one is a long shot.

Heat and electronics are a bad combo. I am not familiar with that particular motor, but if there is any chip/module/etc under the hood, like on top of the distributer, or in the cap etc. That is the first place to look.

Are you sure there is no crank sensor? AFAIK that is the ONE item on most cars that will stop the engine dead cold and it is a high failure rate item as well. Even the computer if dead, on some models will not stop the car from running because the ignition module takes over at fixed timing and allows a limp home mode. It will run like crap, but you will get home!

Bottom line is it sounds like a heat related problem.

Just re-read your message and had another thought.

One other thing, does the oil pressure sensor talk to the computer and shut down things if the pressure goes low? If so, that may be why it was plugged. Map sensor will not shut the car down.

Hi...

Just seems like the world's biggest coincidence so possibly worth mentioning...

15 minutes ago came in from the driveway; wanted to measure the resistance of my coolant temperature sensor. Unplugged it while the motor was running, and it stopped dead.

Wonder if the op's might be thermally intermittent?

Hint might be that when I did it, it left the engine terrible terrible bad flooded.

Ken

The typical symptom of a sick coolant temp sensor is rich running. Disconnecting it AFAIK should NOT stop the engine. Make it run bad, yes, but stop it? No....

Sounds like a coincidence to me. My 92 Caprice will run without any sensor EXCEPT: TPS shorted close (car will not start with wide open throttle).

I'm starting to think you have some sort of a B+ voltage problem either a bad ground or something along those lines. However the 15 minute thing suggests heat.

On most cars you can unplug everything, EXCEPT crankshaft sensor, distributer ref signal (same thing) or a shorted TPS and the car will run.

Seeing as the oil pressure sensor was plugged, I would start there. You might have low oil pressure and the new sensor you installed is telling the computer to shutdown. Some cars shut down on low oil pressure, others do not. I do not know what your engine does but it is a thought. Why was the sensor removed and plugged in the first place? Food for thought.

Let me add that the car did the same thing before all the new parts were added. Eprom chip didn't help, oil sensor either, map and O2 didn't phase it.

So to answer your question, he can check the schematics about the oil sensor, It does read good, showing 60 psi when started, whereas when it was plugged, the gauge just pegged out. Have no clue why it was plugged, it was bought in that condition.

Thanks for your help, we'll be checking your suggestions in the morning.

Jack,

In that location, there is a knock sensor. He has one, and will change it out. Are we missing something?

He has the oil sensor with 3 wires, the oil sensor with 4 wires talks to the computer. Also, Autozone's books say that crank sensor is not required for this model.

Also, more info, it wasn't mentioned that he does get a voltage on the coil after shut down and doesn't get a voltage after shut down on the fuel relay and the injectors in the throttle body.

He is changing out the knock sensor, and says Autozone will check his ECM module, so I'll check back here with the results later.

Really appreciate everyone's input!

Paul

Not a lot of room to get at it, but that's where it's located. There a wire running from it to the coil pack modular.

Not on a 91, it has a distributor.

Are you sure I had a 1990 and it had fuel injectors with the coil pack. Definitely no distributor!

If it does indeed have a distributer, does it have the little ignition module under or on top of the cap? If under the cap, it is very important to have thermal grease on it or it will overheat and cause this exact symptom. Walter

P.S Changing the knock sensor won't do anything for this problem.

I took the module out and it did have terminal grease on it it was hot .I also took to auto zone and had them run it on there tester machine and it was tested 7x and all times it tested good,>I now have anew problem due to the old connectors being dry rotted now i cant figure out how the wires go I put them back the way i thought they were and it aint working ..at all >the rain came and i came in....>>>need to now know the wire colors and how they go ..

Not in a minivan you didn't.

Then it had to be a different chassis.

I dont know?But it does have a distributer

THERMAL grease, not "terminal grease." Thermal grease goes on the base of the module, it helps conduct heat away into the distributor housing (heat sink).

Module testers are a gross waste of time.

If you're saying that the plastic connectors inside the distributor that hold the wire terminals for the module are all rotted away, then it's time for a new (rebuilt) distributor. Ozone from rotor to cap arcing is what destroys the connectors, it it has attacked the plastic connectors, odds are that the pole piece in the distributor has suffered likewise.

Sorry, your right it was a sedan.