Engine cuts out

[Lsixer]

Since this place (our e24 sub-forum) nas become almost as busy as OT here, I looked for a bit for some comparitive issues that I am having.

I found a similar condition on bigcoupe, but when I bumped the thread, no one responded.

http://bigcoupe.com/phpBB2/viewtopic.php?t=11056

Here is what I am encountering. I copied this from my bigcoupe post.

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I have been reading all morning in an effort to find a similar scenario as to what I have been expereincing. This is close, but, not 100%

I always store my 1987 L6 in the winter, heated garage, while making sure to at least every two to three weeks, starting it up and letting it idle for about 15 to 20 minutes to keep the battery up and all around engine functions. I usually putter around in or around the garage while this is happening just to make sure for one I dont forget about it and leave it running until the gas is gone.

Just a little over a month ago, we had several nice days, around 30 degrees, completly dry streets so I decided I would actually take it for a quick drive. I started it up, let it run about 5 minutes, and took off. I was five minutes into the drive, and just pulled onto an EXTREMELY busy four lane road with a 50 mph speedlimit and the damn thing died. I seriously felt a brown trouser moment coming on.

I immediatly started cranking, cranking, and finally by the grace of God it started and I was able to speed the hell out of the way. I subsequently took it on a highway for about twenty minutes to a favorite watering hole of mine and it sat for about an hour. I came out and it started and idled fine, and I had no issues on the way back home, same route, highway, other 50mph streets, etc ....

Since then, I have started it in the garage twice to let it run, and now both times after idling about five to ten minutes, it stalls. It then struggles to start, just as it did when I was stuck on the four lane road. I have to depress the gas pedal several times, not holding it down, just several depresses just to coax it back to life.

Could this be a result of what was discussed above? (the posts on bigcoupe)

I have not replaced the O2 sensor ever. I have owned the car ten years now and have put 30k on it over those ten years. Most of that mileage was in the first three years of ownership. It rarely gets 500 miles a year these days.
The O2 is on my todo list whether or not it is the culprit here.

Help?

[rem83]

if it's dying reliably, the easy way to test to see if it's the o2 sensor is to unplug the sensor, let it run open loop and see if it still dies. other than that, there's not enough information here for me to come up with an opinion.

[Lsixer]

if it's dying reliably, the easy way to test to see if it's the o2 sensor is to unplug the sensor, let it run open loop and see if it still dies. other than that, there's not enough information here for me to come up with an opinion.

Forgive my ignorance. Will the car run without the O2 connected? Where would you recommend (which location) disconnecting it for a test?

I do plan on replacing it. I am just trying to determine if this is the issue or if there are others problems as well.

[rem83]

yeah - o2 is just for adjusting fuel trim, all the car really needs is the afm (or maf, i forget what these use) output to tell it where in the fuel map it should be, and then o2 sensor output tweaks that to give a big improvement in emissions. the o2 sensor doesn't even work for the first few minutes the vehicle is running. the danger with the o2 sensor is that if it gives dramatically wrong readings, it can screw with the ecu enough to make the car run poorly.

on my obdII equipped cars, one of the outputs is open / closed loop fuel control, so you can watch the scangauge readout and see when it switches over. if you just unplug the o2 sensor (i believe there's a connector under / around the oil filter housing - that's where i'd unplug it) the ecu should default to run in open loop.

replacing it with a generic 4 wire bosch sensor isn't a big deal, but i ended up dropping the exhaust so i could figure out how to remove that little shield that goes over the sensor, as well as replace the flex disc and shift linkage parts.

[Lsixer]

I'll have a look tonight to see if I can get my gorilla hands in there by the oil filter housing and disconnect it.

Jeez this has been the car repair week from hell. The six is misbehaving, the wifes jetta needs the brake pads changed, and now I discovered my stabilizer links on my rubicon are shot.

What else can go wrong? :rolleyes

[Alex E24 E30]

Mine was doing something similar about a week ago:

At least once (sometimes as many as eight times) while driving around town, which is rarely more than a 15 min stint for me, the car would die. It always died at idle speed, and half the time the car had been idling for a little while (no more than 3-5 min) and half the time it was dying when I hit the clutch to go into neural while slowing down. I cleaned the aux. air valve (early motronic ICV) and it works like a charm now.

Mine was pretty sporadic, though. It had been doing that on and off. Might go a week without it dying, and then all of a sudden a trip to the grocery store would be a complete nightmare. Maybe check this out along with the 02 sensor?


Alex

[Lsixer]

Mine was doing something similar about a week ago:

At least once (sometimes as many as eight times) while driving around town, which is rarely more than a 15 min stint for me, the car would die. It always died at idle speed, and half the time the car had been idling for a little while (no more than 3-5 min) and half the time it was dying when I hit the clutch to go into neural while slowing down. I cleaned the aux. air valve (early motronic ICV) and it works like a charm now.

Mine was pretty sporadic, though. It had been doing that on and off. Might go a week without it dying, and then all of a sudden a trip to the grocery store would be a complete nightmare. Maybe check this out along with the 02 sensor?


Alex


Any tips on cleaning the valve? What did you use? I'll have a look at realoem to ID where it is on mine. Any clues are appreciated.