I have been trying to figure out a rich running problem for some while. I have an 1985 760 Turbo with 185000 miles. The initial symptoms were the car would run for 5-10 minutes and then choke - I would wait and then start again, go 2 miles and it dies again. After being towed home I spent the next 6 months trying to fix the problem - after many parts, time, and research I have learned a lot about the car but not yet fixed the problem.

Car will start and run fine but O2 sensor reads between 8.9 and 9.3 Volts meaning a rich mixture - will typically choke on gas about 15-20 minutes after running.

Here is what has been in order over a 6 month:

-Throttle Body cleaned
-Fuel pressure regulator has been replaced
-Fuel relay checked – operational
-Injector Ballasts tested for proper resistance - check
-Fuel pumps both working – audible
-All fuses intact
-Air filter clean
-RPM gauge jumps when cranking - assume operational
-Cap and Rotor replaced
-Coil to Distributor Wire Replaced
-Coil swapped with new coil - no fix
-Engine Temp Sensor replaced
-Air Mass Meter swapped - no change
-O2 sensor replaced - readings are true - leans when induce air leak
-Engine wire harness - removed - much corrosion, replaced all bad wiring and --installed
-Injectors cleaned and balanced.
-Engine computer swapped - no fix




If anyone has any ideas I would love to hear your thoughts.

Today I went to feel the Air hose coming into the Intercooler and noticed that it was quite soft - as this there was no pressure there when idling - as was the hose into the throttle body - I seem to remember those hoses having some pressure when idling. Also the CBV valve hoses seem to be tight as though air is circulating through it - Is this normal at idle? Could it be that the engine is Air starved because of a bad CBV valve to cause a rich condition?

Are there any critical vacuum lines I need to check for leaks? Would that cause such drastic problems?

Thank you