I have a 73 30.CSi with a 1987 535i engine. The car was running fine until it was rear ended. Upon impact, the engine shut off and it hasn't run since. The problem was no positive spark to the fuel injectors. When cranking, both injector wires were negative. The ecm was suspected, but the installation of two different ecms did not solve the problem. Putting a new air flow controller on restored the positive signal to the fuel injectors, but the mechanic says it doesn't receive enough voltage to run. The current mechanic (it has been to 4 shops)is always under a hood when I call and I am convinced he isn't working on it. Any ideas?