My 1990 740 turbo has been running rough (and I suspect, rich).

Along with cleaning the throttle body and replacing the FPR, I recently sent the fuel injectors out to be reconditioned, and they were returned with test results showing that they were "fair" when I send them and good when they were returned.

I've never really gotten the car running right.

And I just found that...

One of the injectors is apparently not functioning. When I pull the wire from it while the car idles, there is no change (pulling the wires from the other three causes immediate change).

I am testing 12 volts at the "bad" injector's plug (positive multimeter probe in the socket, negative to the engine ground).

What gives? I doubt the injector itself is bad, it having just been rebuilt.

I've cleaned and re-secured the injector wires ground connections at the intake manifold, to no avail.

Any ideas? I'd love to fix this today (the car is for sale).

Many thanks,

m rad