92 325is electrical engine problems - help please!

[johndrowe]

Hi there.. long time reader, first time poster and hoping someone may be able to help me out.

I recently purchased a single owner '92 325is with 108k miles in excellent condition (no rust, damage, etc.). Since driving it over the past few weeks, I have noticed some minor problems which I am hoping someone might be able to find a common point of failure on. You'll see as it goes the issues got worse. kind of.

Initially, the only problem within the first week was an erratic sunroof. Sometimes the button would work, sometimes it would do nothing. No biggie. A few days later, I noticed that occasionally the brightness of all interior and exterior lights and the sounds (whining) of I beleive an aftermarket fuel pump would oscillate from high to low. This would occur, but not in relation to the engine RPM's.

After about another week or so, the issue got a bit worse and was causing the CEL light to blink off and on for a while, then would go away. It never stayed on solid. During a 4 hour drive, it would come on maybe 5 times for less than 45 seconds in each occurance. Power to the engine was not affected when this occured, and the idle was not impacted in any way. This continued for a few more days.

Also occasionally, I would receive a brake light circuit message on the OBC. This seemed to mainly happen after washing the car, and was very intermittent and rare. Only happened a few times since I've had the car, and each time the lights were all working properly when the message came on. (Car has stock tail lights)

This past weekend, I was on my drive home and started smelling gas badly. Pulled over and to no avail after pulling out the backseat found one of the fuel lines had wiggled almost completely off the fuel pump. Put on a new Hose Clamp, and the problem was solved. Was able to drive home that night. The next day, I went out to try and look further into the oscilating lights issue, and noticed a few things.

1) The lights/fuel pump only oscillated when the car was running.
2) Both Belts were just replaced 1 week ago and tension is fine.
3) Battery does not lose charge and is steady at 12.5 when car is off.
4) When car is running, get a steady 14.1 Volt reading from the Cigarette Lighter when checked leading me to believe the charging system is working fine.
5) While checking the voltage, I pressed the button to turn on the air conditioner, and nothing happened. After pressing it a few more times, it finally kicked on. I found this same behavior also with the rear defroster and the recirculate button. Sometimes they would work, sometimes not. Previously, none of them gave me any issues.
6) I checked the CEL codes, and the only thing it was reading was 1231 (Battery Voltage/DME Main Relay).

At the recommendation of a friend, I checked the battery terminals, and the positive was a bit loose. (Not loose enough to come off, but when you twist it there was a very slight bit of play). To fix this, I disconnected the positive wire all the way, reseated it, and tightened it up to spec to ensure it's not a loose connection. Double checked all fuses and everything is fine.

Here is where it got a bit screwy...

Once the battery was reconnected, the high/low oscillating of the lights has stopped occuring. Also, no more erratic noise from the fuel pump. AND no check engine light. However, now the car is running rough. Almost appears like th etiming is off, and it occasionally backfires. It idles at a constant 650 RPM, (needle doesn't move) but you can hear a miss. When you give it gas, it occasionally backfires. If you try and drive it, it is much more noticeable, as well as a major loss in power when running below 1800rpm. Once you hit the 1800rpm mark, it sometimes runs fine, but then cuts in and out.

I've gone over all the grounds, the battery terminals, etc. and cannot figure out what may be open or shorting causing this to be impacted. I've also reset the ECU again with no change. I'm hoping based on the history I've given that someone may have some insight as to what could cause it to go to crap just by disconnecting and reconnecting the battery. The CEL has not come on since the battery was first detected, and a code check now just gives 1444 (normal).

Also, I noticed one other possible clue in my driveway while checking other things. I found a piece of black plastic tubing (it appears) laying on the ground, and have NOT been able to figure out where on the car it came from. It has the following numbers listed on it "BMW 61.66-8 353 883" then below that is ">PA6-GF 15<". It is 8 1/2 inches long, and roughly 5/8 inch wide. It has 10 small tabs on the outside (5 on each side) and also a wire retainer on one side with space for two wires/cables. It appears to be only HALF of something, but after crawling around under the car I am unable to locate the other half to know where it came from. I tried attaching a picture of it to this message, with a pen as a reference for size but the upload failed. It can be viewed or downloaded here: http://www.rmmhosting.net/bmwmissingpiece.jpg



I have a copy of the Bentley 92-99 E36 manual, so please feel free to reference it if needed. I live in the sticks in Northern Pennsylvania and the soonest appt I can get with a mechanic is at least 5 days out.

My two biggest concerns are: 1) what is causing the engine to run this way now (all of the sudden after reseting system) and 2) what the heck was this plastic piece covering that might now be exposed an causing issues.

Thanks in advance for your time and ANY help or hints you can give me at all... it;s my main transportation and I'm pretty desperate to get it back on the road so I can pick up my kids this weekend.

J.D. Rowe
rowemultimedia@gmail.com

[motorwerks]

Your plastic piece shouldn't be the cause of your issues- http://www.realoem.com/bmw/showparts...61&fg=45&hl=62


Check your trunk harness for wear, and shorts. There have been a number of cases where the shorting of the wires in this harness have caused cars to act erratically.