I bought this car last year for my daughter because it is in great shape and when it runs it rides like air. It has the 3.3l V6 and it just randomly stalls. sometimes sitting still, sometimes driving down the road. I've been trying to track down the issue with it for quite a while but I'm getting ready to just scrap it. I'm very adept in mechanics and electronics, but this thing has kicked my butt! I've replaced just about every sensor, coil pack and ECM, but nothing solves it. the old man I bought it from fought it for a while as well. I see this is a common issue with these cars, but there doesn't seem to be any definitive answer to the issue.... anyone have any ideas before I'm forced to end this beautiful Station wagon's existence?
Sometimes either way. Last week I did a bit of work on it. It started and ran better than ever. I let it sit and idle for 10-15 minutes and then decided to test drive it. Drove 2 feet and it shut off like I turned the key off. tried to restart it and it tried to run, but just sputter a little and won't run. But sometimes it starts right up and will drive for a while. I've been over everything and just have no idea...
Yes, it wasnt very stable at first, put a new regulator in it and holds about 40lbs right on the money...
New crank position sensor x2, new ICM and coils, new fuel pump and filter, new MAF sensor, new throttle position sensor, new ECM, new fuel pressure regulator....
I saw this happen on an 84 Buick which turned out to be varnish in the tank & fuel lines causing a momentary blockage, we had to drop the tank clean everything, ( we also made sure the fuel pump wiring and connections in the tank were good) replaced the pickup screen and flushed the fuel lines. Once that was done along with another new filter the car worked great. Your issue could be different but it might be worth a check.
Yeah, I have already pulled the tank and changed all of that... have good and consistant fuel pressure.
1) Have you pulled codes? 2) I noticed you didn't say anything about the dash lights--do they come on when it stalls? I've run into this symptom before, even on my '79 Malibu wagon I used to own, where I had to drop the column and pull the ignition switch, to inspect and bench-test it. On the ignition power circuit, it had a very high resistance, so I replaced the switch. I took the old one apart, found that the contacts inside were all variously burned, but the ignition circuit one was really burned. Also, since the switch is adjustable, verify the two bolts aren't loosening, and lube the actuator assembly inside the column head.
Checked the codes initially and got the same result as the old man I bought it from. Crank position sensor. The aluminum holder was physically cracked, so I changed it with an Autozone one. Heading the advice of a mechanic friend, I changed that out with an AC Delco one because he said the aftermarket ones often don't work out of the box (mechanic friend lives 1100 miles away why I don't pay him to fix it). The ignition switch was my next thought as well as checking or omitting the catalytic converter, as it is more likely to fail if it is warm. But I am skeptical about the cat being plugged because the car runs very strong when it's not stalling...
The cat is either flowing or choking the engine off. No in-between. But you can check the vacuum at idle, a good engine should be 18-22" at idle. As for the crank sensor, two problems: incorrect Hall Effect magnet-to-shutter distance (should be the thickness of a business card when set) or shattered Hall Sensor (contact with shutter either on assembly of crank damper or when engine is cranked over). Since you didn't mention the latter, I would go ahead and reset the sensor-to-shutter gap. There should be a bolt in the bracket that allows the sensor to be slid side-to-side (been a long while since I've dealt with the 3300 and 3800 Series 1) ; loosen it. Mark the damper at the sensor location; remove the damper bolt and damper. if there's damage, replace the sensor. If not, take a piece of business card, slip it into the outer groove (nearer to the connector), then carefully slip the damper on as you jockey the sensor into position so that the card ends up outside the outer shutter. Finish the damper reinstall, then gently push the sensor against the shutter and tighten the bracket bolt. When the engine starts, the card piece will come out, and you'll have the correct distance.
I'd go back to the basics. When it stalls and won't start do you have spark? Do you have fuel (pressure on the rail and injectors pulsing)? Andrew brings up some good points on the ignition switch and setting the CKPS. I would also check the crank damper for wobble while it is running.
Good point on the damper wobble, plus if there's even slight bending to the shutters. All it takes is one dumb-assed thing done to mess up the works.
I had an '89 Century sedan with a 3.3 and it was a nice little car. My 'impossible to fix' problem on that car turned out to be a cracked coil pack tower. It would short out in damp weather. After several shops couldn't diagnose it, I found the problem myself by misting the engine with water at night and finding sparking on the coil. I once read that the wiring harness going down to the crank sensor on a 3.3 would get chafed inside the wrapping and the wires would intermittently short out. Have you pulled the wires from the harness and checked them?