91 Lumina APV dies after 15 minutes

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Trying to help out one of my guys who bought a 91 Lumina APV 3.1L from the state auction. 137K miles, wasn't running long when he bought it. Changed
out a variety of things, first on the list was a new battery, then ordered a new eprom chip, since it was missing from the computer. The computer looked like it had been changed out, and whoever worked on it last gave up, since there was no eprom chip in it, and was left hanging on the floor when purchased.
Next he installed new plugs, wires, cap and rotor. Oil pressure sending unit was missing, had a plug in the block, new one was purchased and installed, seems to be working fine now. Fuel filter was changed, the old one drained into a jar where where we could see there was a considerable amount of trash in it.
So now the computer gives no codes when it's started when cold, and dies completely after getting warmed up, generally right at 15 minutes of running. Everything seems to shut down, ignition and TBFI when it dies. Computer has given out a variety of codes when the motor dies, for mapp sensor and O2 sensor. Those were replaced on the assumption that he's rather know he had good parts than to wonder about them. Knock sensor shows 12V when running, book says it should be 6-10V, and does not retard when he clanks on the side of the block.
Thought it was a good chance the crank sensor goes out when it warms up, but the Haynes manual doesn't show one for that engine/motor combo, and he doesn't see one. Although most models seem to have one, this one apparently doesn't, or we're too ignorant to spot it.. ;-).
The ECM module hasn't been tested, although I thought that should have been one of the first things checked. Also the fuel pressure and signs of water in the gas hasn't been checked, but I believe we're going to check it in the morning.
Any thoughts on what could be causing this? Appreciate any replies, if more info is needed, I can pass it on....
Paul
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On Fri, 27 May 2005 17:18:40 -0500, Paul wrote:

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.
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Walter wrote:

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
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On Fri, 27 May 2005 22:54:06 +0000, Ken Weitzel wrote:

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.
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The crank senor on the 3.1L is located underneath the car between the transmission and top of oil pan.

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

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Not on a 91, it has a distributor.
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Are you sure I had a 1990 and it had fuel injectors with the coil pack. Definitely no distributor!
wrote:

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It defiantely has a distributer
Jack wrote:

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On Sat, 28 May 2005 15:15:02 -0700, Painterpaul wrote:

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.
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Walter wrote:

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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 ..
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In article

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.
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Not in a minivan you didn't.

Then it had to be a different chassis.
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I dont know?But it does have a distributer
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Sorry, your right it was a sedan.
wrote:

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Its ok Jack ! And Just priced the new distyributor and they want another $109 and it dont come with the new ignition module..ouchthey have to order be calling around
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Got The new distributor..Now if the rain would leave us alone I can get out and work on it..
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Well It appears I had to change the entire distributer.. it could of been the module or the coil inside the distributer .It has run for 20 minutes in the parking spot then road tested around the block with the a/c for 40 more minutes ,then I shut down the motor and restarted it with no problem!!
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