My E30 is healthy again! (or, good sensors are important)

For a very long time (over two years), I've been living with a condition where my E30 starts hard in the cold (see http://bmwe30network.net/forums/read.php?3,813,813#msg-813). I've tested every electrical connection I could think of, and replaced the AFM (it was throwing a 1215 code, which is the AFM), the ECU, the coolant temp sensor, the intake boot, the fuel pressure regulator, and probably some other things as well, all to no avail.

Last winter I finally took it to a well-respected mechanic about an hour away who knows old BMWs. He swapped in a different ECU, which fixed the problem (which is why I replaced the ECU). But after a day or two with the new ECU, the problem returned. I suppose the computer adapted itself to my engine, and I was back to square one, with the 1215 code and hard cold starting.

Then a couple weeks ago a new problem arose, where the car would hesitate when hot, especially after a long drive and under power. Last week it got so bad that I could hardly drive the car any more, so it took it back to the same mechanic and explained everything that was going on. Fortunately, this guy got it, understood the problems, was able to duplicate them, and began a thorough troubleshooting procedure. To make a long story short (too late, I know), I actually had two problems.

Problem 1, the hard starting, was in fact caused by a bad coolant temp sensor. This was the very first thing I had guessed, and the first thing I replaced way back when this first started! But my mistake was not knowing one aftermarket brand from another. The one I had bought was an FAE sensor. The mechanic took a look at it, recognized it as an FAE sensor, and told me that he had had nothing but problems with FAE stuff. He replaced it with a Bosch sensor, and bingo! Problem solved! Who knew?

Problem 2, the warm hesitation under power, was completely unrelated. It turned out to be a damaged crank angle sensor. It had gotten to the point where occasionally the ECU would not get data on the crank angle, so it would simply shut down the engine. That was bad. Again, another new sensor fixed the problem. Related to this was a new code 1222, which was caused by a faulty oxygen sensor. We replaced that sensor as well.

Now the codes are all cleared, it runs like a top, it starts beautifully, and I took it on a 5-hour drive with not a problem (especially nice since I also fixed the A/C last year ). It's like a new car! I could not be happier, and I'm in love with my old car all over again.

Two important lessons learned from this experience:

1. Never again will I buy FAE electrical parts. Bosch it shall be.

2. It is invaluable to know a skilled mechanic who knows and understands old BMWs.

Perhaps this will help someone else in the future.

__________
Dave
'91 325iX

Quote
Dave_G
For a very long time (over two years), I've been living with a condition where my E30 starts hard in the cold (see http://bmwe30network.net/forums/read.php?3,813,813#msg-813). I've tested every electrical connection I could think of, and replaced the AFM (it was throwing a 1215 code, which is the AFM), the ECU, the coolant temp sensor, the intake boot, the fuel pressure regulator, and probably some other things as well, all to no avail.

Last winter I finally took it to a well-respected mechanic about an hour away who knows old BMWs. He swapped in a different ECU, which fixed the problem (which is why I replaced the ECU). But after a day or two with the new ECU, the problem returned. I suppose the computer adapted itself to my engine, and I was back to square one, with the 1215 code and hard cold starting.

Then a couple weeks ago a new problem arose, where the car would hesitate when hot, especially after a long drive and under power. Last week it got so bad that I could hardly drive the car any more, so it took it back to the same mechanic and explained everything that was going on. Fortunately, this guy got it, understood the problems, was able to duplicate them, and began a thorough troubleshooting procedure. To make a long story short (too late, I know), I actually had two problems.

Problem 1, the hard starting, was in fact caused by a bad coolant temp sensor. This was the very first thing I had guessed, and the first thing I replaced way back when this first started! But my mistake was not knowing one aftermarket brand from another. The one I had bought was an FAE sensor. The mechanic took a look at it, recognized it as an FAE sensor, and told me that he had had nothing but problems with FAE stuff. He replaced it with a Bosch sensor, and bingo! Problem solved! Who knew?

Problem 2, the warm hesitation under power, was completely unrelated. It turned out to be a damaged crank angle sensor. It had gotten to the point where occasionally the ECU would not get data on the crank angle, so it would simply shut down the engine. That was bad. Again, another new sensor fixed the problem. Related to this was a new code 1222, which was caused by a faulty oxygen sensor. We replaced that sensor as well.

Now the codes are all cleared, it runs like a top, it starts beautifully, and I took it on a 5-hour drive with not a problem (especially nice since I also fixed the A/C last year ). It's like a new car! I could not be happier, and I'm in love with my old car all over again.

Two important lessons learned from this experience:

1. Never again will I buy FAE electrical parts. Bosch it shall be.

2. It is invaluable to know a skilled mechanic who knows and understands old BMWs.

Perhaps this will help someone else in the future.

Very interesting nice going Dave, it's great when you can get to the heart of things.

Rick

crank angle sensor...
what is/where is it?
please see my post 'back from Vegas' above.
could it be?

thankS

nevermind, looked at bimmerforums, as usual...