I am working on a 1991 735i automatic trans car with 200,000 miles on it. It slowly began to degrade in performance until it will no longer even start. I changed plugs (severely carbon fowled and wet with fuel), hooked up a fuel gage (reads 40-45 lbs while cranking and holds pressure after shutoff), checked to ensure spark (check good), tested plug wires (all between 5k ohm and 7k ohm, and hooked up an injector tester to verify injector pulsing (also good). I happen to have a complete injection system recently striped from another running 1991 735i that I am in the process of installing on my 1980 euro 635CSi to help control it’s T4 intercooled cartech turbo, so I’ve tried swapping out the ignition computer as well as the air flow meter, neither produced any effect.

Now I’m stumped. Certainly if the mixture is off or it is in limp mode (open loop) it should run for a while until the new plugs fowl. If any one out there has run into a similar problem please let me know.

Thanks