95 olds just dies

[model a vette]

I went thru the same sort of problem on my 88 2.8 Chevy a few months ago. Symptom was engine suddenly stopped running. No light or code set. First time it had run for about 3 miles. Towed home. Second time 2 miles. Towed home.
I changed the control module, under the coil packs, a couple of times, with cheap junk yard spares. No change. Engine would die idleing after 3 minutes.
I finally changed the crank position sensor. I also cleaned the oil out of the "sealed" wire conectors. Problem solved!

My 2.8 is the earlier version of your 3.1 engine, if yours is the 60 degree V6. The 2.8 only has the one CP sensor. It is located above the oil pan rail between the engine and trans. I broke the top off the old sensor trying to remove it.
I finally bit the bullet and removed the oil pan to push the sensor out from the inside. Some have suggested that the sensor can be pushed into the engine and be allowed to drop into the pan. I'm not sure I could have gotten enough force on it to drive it into the pan. I could just barely get my hand between the engine and trans.

[rooster]

I went thru the same sort of problem on my 88 2.8 Chevy a few months ago. Symptom was engine suddenly stopped running. No light or code set. First time it had run for about 3 miles. Towed home. Second time 2 miles. Towed home.
I changed the control module, under the coil packs, a couple of times, with cheap junk yard spares. No change. Engine would die idleing after 3 minutes.
I finally changed the crank position sensor. I also cleaned the oil out of the "sealed" wire conectors. Problem solved!
.

Shouldnt this have set a code in your obd1 system?

While I had the coil pack off for testing (its ok) I replaced the crank sensor , was not easy but it did come right out, I filled the engine compartment with blankets and sorta made a bed so I could lay down an reach down with a socket.

The wires I checked looked ok, found nothing melted, the plugs were clean.

I put everything back together and fired it up , 57 munites later it died, eng temp 225-230.  No lights came on in the dash. Test done at idle .
I think im going to Wayens test with the light when this temp is so high.

I still have all the grounds to clean on the raditor support to go. I checked the milage on the car today it just rolled over 64000 miles, she dosent drive it 30 miles a week

Later Rooster
Denny

[model a vette]

"Shouldn't this have set a code in your obd1 system?"

No, there is no provision for a defective CPS to set a code.
I read the service manual and it describes the way the CPS works with the coil module:
The CPS sends a signal to the module and the module uses that below 400 RPM without input from the ECM. If there is no signal from the CPS the Module doesn't trigger the coils. I guess since the ECM is not involved in this part (below 400 RPM) GM didn't think it was neccesary to provide a code.
In OBDII cars there is a second position sensor behind the timing cover.
I think the second sensor was added as a backup to the original one sensor design. I guess having two sensors makes it even more fun trying to diagnose a problem.  :(D)

"eng temp 225-230"
The fan on my car is set to come on at 223-227 according to the manual, so your temp reading is not that high after idleing that long. Did your fan come on?

I've heard that bad grounds can cause a problem but I don't think they would take so much time to stop the engine.

I did have a coil module, once,  that would take some time to stop the engine. It seems like heat was the problem. Any chance of getting a cheap junkyard spare to test with?
Is your coil pack mounted on top of the engine near the firewall?
I got to be pretty fast at removing that type last Spring!
Mine is the older style with the module and coils mounted to the block near the radiator. The fan and shroud has to come out on mine to replace the module.

[rooster]

"eng temp 225-230"
The fan on my car is set to come on at 223-227 according to the manual, so your temp reading is not that high after idleing that long. Did your fan come on?




What manual do you have? The Haynes manual is not great!

Yes, the puller fan comes on at about 225-230 deg (I have a guage)
I think this temp high! The guage built into the olds dash is right to the red mark.

In the idle test in the driveway that is usually when the engine dies , 230 degrees., but then the engine will restart and the fan do its job.

In the driving test (under a load) the can die at any point , not even up to operating temp or maybe operating temp.

It seems I can control the test in the drivway by turning on the AC , witch starts the puller fan and takes the temp down to 200 ands stays there, but the fans stays on to.  I never see the small pusher fan come on.

My coil pack is back by the firewall, as far as I can tell I only have 1 sensor.  Gonna have to do some junk yard shopping and get some backup, we just junked 3 of are cars the had DIS and good computers.

Im begining to think there is more than one problem. I guess I could disconect something and see if it will set a code.

Denny

[Fat Cat]

Yes, the puller fan comes on at about 225-230 deg (I have a guage)
I think this temp high! The guage built into the olds dash is right to the red mark.

Denny

225-230 is not a lot of heat for the newer cars. Some of the much newer cars run in the 240-250 range. The reason for this is that the hotter you can run it the more complete the combustion which means lower emissions. Running these cars in this heat range is why the fuel they sell today is not very friendly to our older cars with carbs on them. They run the cars on the leaner side of things and have formulated the fules to atomize at much lower temps to get every BTU they can out of the fuel in the combustion chamber.

[model a vette]

"What manual do you have?"

The GM shop manual for my specific car (1988 Celebrity).

I have found the Hayes Manuals to be the best of the aftermarket manuals but they usually do not have as much detail on how GM designed things.

In case you ever need to turn the fan on easily just short the A & B terminals on the ALDL connector. I think this may disable the setting of codes but sometimes you may want the fan on without the AC.

I think that your dual fan setup has one fan coming on at about the same temp as my fan and then the second one comes on at a higher (and scarier!) temp.

[wayne petty]

just in case people don't know...

online auto repair manuals...

autozone.com...     log in at the extreme upper right corner... its free.. cover a LOT of cars... including some of the 05 models... and back to the early 50s for jeeps and mid 60s for many other models..


http://www.eautorepair.net       this is mitchell information systems consumer info site..  mitchell is i think owned by snap on...

http://alldatadiy.com/      alldata is actually owned by autozone .. and there are subscription kits in stores..


for printed manuals.. and manuals on CD... one of the many sources is

http://www.faxonautoliterature.com/

[wayne petty]

3.1 spark control

http://repairguide.autozone.com/znetrgs/repair_guide_content/en_us/images/0996b43f/80/21/66/d4/large/0996b43f802166d4.gif

http://repairguide.autozone.com/znetrgs/repair_guide_content/en_us/images/0996b43f/80/21/66/d5/large/0996b43f802166d5.gif


what the az site does not show is the charts 1  through  7... as these are the first places to start...

they are only available in the factory service manuals... and on the payed sites...

or if you can talk some shop out of print outs that has a subscription...



i am going to take a leap....   if you can swap the crank angle sensor behind the damper...    or drive it till the check engine light comes back on.. then get it scanned again...

something is causing it to shut down...


does you digital volt meter have a duty cycle setting.. or an MS setting??? some do....

if that setting is available...   you can monitor the ecms control of the ground side of the injectors...    see if the pulse width or milliseconds is dropping......

you could also use a harbor freight logic probe...
see if the injectors stop pulsing as the motor starts to die...

you measured the positive side as i recall...

[rooster]

i am going to take a leap....   if you can swap the crank angle sensor behind the damper...    or drive it till the check engine light comes back on.. then get it scanned again...

something is causing it to shut down...


does you digital volt meter have a duty cycle setting.. or an MS setting??? some do....

if that setting is available...   you can monitor the ecms control of the ground side of the injectors...    see if the pulse width or milliseconds is dropping......

you could also use a harbor freight logic probe...
see if the injectors stop pulsing as the motor starts to die...

you measured the positive side as i recall...

No I havent measured anything.

I do have a meter FREQ % duty, is that it?

Off to work now more later.
Denny

[rooster]

i am going to take a leap....   if you can swap the crank angle sensor behind the damper...    or drive it till the check engine light comes back on.. then get it scanned again...

something is causing it to shut down...


does you digital volt meter have a duty cycle setting.. or an MS setting??? some do....

if that setting is available...   you can monitor the ecms control of the ground side of the injectors...    see if the pulse width or milliseconds is dropping......

you could also use a harbor freight logic probe...
see if the injectors stop pulsing as the motor starts to die...

you measured the positive side as i recall...

No I havent measured anything.

I do have a meter FREQ % duty, is that it?

Off to work now more later.
Denny

[rooster]

[quote

something is causing it to shut down...


does you digital volt meter have a duty cycle setting.. or an MS setting??? some do....

if that setting is available...   you can monitor the ecms control of the ground side of the injectors...    see if the pulse width or milliseconds is dropping......

you could also use a harbor freight logic probe...
see if the injectors stop pulsing as the motor starts to die...

you measured the positive side as i recall...[/quote]


I got the Logic probe from HF today, hooked it up it was working ok!

I found the harness for the injectors , its right out in the front easy to get to, the harness also had 2 extra wires that I think are the coolent sensor. I stuck the prob into the #1 injector wire and the LED turned green (ing on) the green led was a steady green key on or eng running.

Im going to do the eng dieing test next with the prob in place, sence the computer powers the injectors I think what you are wanting me to watch for is the steady green light to go out, or momentary go out,
when the eng dies.

Are we on the same page?

PS: When I stuck the probe into the wire the engine began to run better, smother !  Better ground maybe?

[wayne petty]

can you first... unplug and ohm the individual injectors through that multi pin connector...

[rooster]

can you first... unplug and ohm the individual injectors through that multi pin connector...

The injectors buried , it looks like I could get to 1 injector. The plug only has the neg side to get hold of.

[wayne petty]

found the harness for the injectors , its right out in the front easy to get to, the harness also had 2 extra wires that I think are the coolent sensor.


the injectors are all powered up on the positive side... steady power...

the ECM completes the circuit by pulling them to ground...

i seem to recall there is a connector out where you described the harness coming out from under the upper intake....

you should be able to ohm them from there...  i may be wrong...

2 wires for the coolant temp sensor...    one power wire for the injectors... or two....    and 6 individual wires from the injectors to the ECM... its hard to know from this far back...


you might be able to use the logic probe on the crank angle sensor wiring...   so you can see if thats quiting...

[rooster]

Starting the test now