1999 Olds 88 3.8 randomly shuts off while driving
Ok, I will try to explain this issue as best I can: Last Saturday (July 23rd) I was driving to the gas station to top off, for the upcoming week. As I was driving there, the car just shut off. I coasted to an access road,and restarted the car, it fired right up,and was able to drive to the gas station and back home with no further issue. This past Tuesday (July 26th) I was driving down to wait for the papers to arrive, when it suddenly shut off while driving again. As I was heading out to do my deliveries, it did it several times in a row. Was taking about 5 minutes each time to get it to restart. I managed to get it home and have not moved it since.
Here'* what tests I've had done so far: Fuel pressure was tested and there was no issue, had very good pressure. Ignition module and coil packs tested, they all passed. Ran trouble codes, only one showing is P0140,(due to the catalytic converter being missing when I got it) A friend who works at our local O'Reilly parts store, said he had a 3800 v6 that was doing same thing,he said it was the crankshaft position sensor, but I'm not seeing a trouble code for that. A couple years ago, I had a 1987 Ford pickup, that was doing the exact same intermittent shutting off issue as my Olds has, and it was the ignition switch (I'm leaning toward that) So, which one could it be? My car was running perfect otherwise
Here'* what tests I've had done so far: Fuel pressure was tested and there was no issue, had very good pressure. Ignition module and coil packs tested, they all passed. Ran trouble codes, only one showing is P0140,(due to the catalytic converter being missing when I got it) A friend who works at our local O'Reilly parts store, said he had a 3800 v6 that was doing same thing,he said it was the crankshaft position sensor, but I'm not seeing a trouble code for that. A couple years ago, I had a 1987 Ford pickup, that was doing the exact same intermittent shutting off issue as my Olds has, and it was the ignition switch (I'm leaning toward that) So, which one could it be? My car was running perfect otherwise
Which "could" it be? Could be either, could be neither, could be both. These cars will stall out with a bad battery connection if they are moving slow at idle and you press the brake pedal (thereby adding brake lights to the electrical load). Could be that too. I'd suggest diagnostics before guesswork.
Please tell us the pressure. We get lots of folks here that say it is good, then we troubleshoot other things for ages, then find out the actual number and the fuel pressure was low all along.
Yes, a marginal crank sensor will do that on this engine and usually not show a code until it the problem is really bad.
Different planet. Not a great diagnostic conclusion. I'll help reverse this by saying: My 1997 LeSabre has the same ignition switch as your car, and at 251,000 miles (so far) has never had an issue with the ignition switch (knock on wood) and has had what you describe with the crank sensor, also with no codes stored. I believe it sees the crank sensor working after the issue and assumes it is fixed, then drops the code. Not positive on that though.
Which "could" it be? Could be either, could be neither, could be both. These cars will stall out with a bad battery connection if they are moving slow at idle and you press the brake pedal (thereby adding brake lights to the electrical load). Could be that too. I'd suggest diagnostics before guesswork.
Yes, a marginal crank sensor will do that on this engine and usually not show a code until it the problem is really bad.
Different planet. Not a great diagnostic conclusion. I'll help reverse this by saying: My 1997 LeSabre has the same ignition switch as your car, and at 251,000 miles (so far) has never had an issue with the ignition switch (knock on wood) and has had what you describe with the crank sensor, also with no codes stored. I believe it sees the crank sensor working after the issue and assumes it is fixed, then drops the code. Not positive on that though.
Which "could" it be? Could be either, could be neither, could be both. These cars will stall out with a bad battery connection if they are moving slow at idle and you press the brake pedal (thereby adding brake lights to the electrical load). Could be that too. I'd suggest diagnostics before guesswork.
I'd start it and do some wiggle tests of wiring and smack the fuse block and column. See if it'* a loose connection.
While it is idling, pull the vacuum line off of the fuel pressure regulator then plug the vacuum line (now hissing) with something. What does the fuel pressure read now?
Last edited by CathedralCub; Aug 1, 2022 at 10:52 PM. Reason: Elaborated on the word "it"
My car does not have that God forsaken full digital dash crap, except for the gear indicator and odometer displays . The 40 PSI figure i mentioned previously was while driving at moment of stalling (I forgot to mention that,sorry) . I'll check electrical connections as the way it'* been acting is very similar to the ignition switch issue that the pickup I had experiencedThread
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