|
My 1990 740GL NA had very similar problems that turned out to be a bad fuel pressure check valve. It is located (as I remember) on the output line of the fuel pump underneath the car on the driver side. The purpose is to prevent the fuel pressure in the fuel rail from bleeding off back into the tank after the engine is turned off. I diagnosed it by putting a fuel pressure gauge on the fuel injector rail. When running the fuel pressure was about 40 PSI. When the engine was turned off the pressure bled off to zero in less than one minute. I replaced the check valve and the rail doesn't lose any pressure, not even over a weekend.
Good luck.
|