91 525i DME

Look to where the power comes from, the main relay.

I have replaced air mass, main relay, checked fuses, sensors, checked all lines, tested electrical-traced wiring even replaced the engine harness! I am ready to light the car on fire!!!! Any suggestions?

send the last 7 of the VIN please

Thank you Dr. Hagerty for your help
the vin# WBAHD531XMBF95698

The DME may be at fault. There are several numbers on the DME, tell me those numbers please.

We also exchanged DME with another vehicle's DME-(same year and model) and that didn't make a difference. Best way without spending $$.

Monitor the fuel pressure, maybe it has a plugged fuel filter or a pump that's close to the brink.

We did this also, actually early on. I'm telling you this car is frustrating!

So you have a car that seems to be cutting out or dying at about 10 minutes into the drive cycle, you have done everything you can reasonably do, and you are at your wits end. The DME power is mysteriously going somewhere, but you dont where. You have thrown the kitchen sink at it. I would say that the thing to do is to find someone who has, or has access to the proprietary scan tool for the BMW cars of that era. It is called a GT-1 and it can monitor the live data stream, and display stored faults.

We had the Autologic Computer Diagnostic test 2 different times. It can not read fault codes!!

There is a good place to start. If the codes can't be read then the issue might be the communication bus is shorted or otherwise inoperative.

We had the comm.bus checked / tested.

Did you now. What did you find.