Been fighting this for a couple weeks now.

It's a 1990 740 Turbo, 155K miles, has run fantastic up until this.

Car starts fine cold, runs good for about 5 minutes or so, then will start billowing black smoke out the pipe and barely runs. It will move the needle from about half, to nearly Empty in 40 miles. It gets extremely bad when you try to boost it.

Ive pulled the codes, and the only stored code was an 02 sensor, which is likely a false code due to being rich.

Cat isnt blocked up.
Turbo inlet pipe isnt leaking air, although it is in rough shape.

All the sensor pigtails are installed and tight, I also cleaned the wires to the injectors.

Cant figure it out, and dont have the money to throw at it hoping to fix it. Local tech said it was a hung injector, that it was pooling and was running real rich when you got on it..but that didnt make any sense because its indirect multi-port injection.

Also a hung injector will do it all the time, and I dont see a single injector using that much fuel, not even running full bore.

Im thinking its a sensor giving a bad reading when the engine warms up and comes out of closed loop mode...I just dont know what sensors can cause this, or how to test them.

Thank you for any help you can give me!

 

could be the ECT (engine coolant tempature): http://www.vcoa.org/700-900-faq/Engi...eratureSensors

and try this link for the symptoms: http://www.vcoa.org/700-900-faq/Engi...rationECTTPSFI

 

Fuel pressure regulator could be busted. Pull off the vacuum line and see if gas is coming out.

 

No fuel coming out of the regulator,

Ill try replacing the ECT sensor and hope that does it.

 

You can also connect a volt meter up to the O2 sensor and see if it is sweeping.