Hi. I was recently given a 91 740t that hasn't run in years, was parked not running I believe and I'm trying to bring it back to life. I'm a pretty good mechanic on most fronts but not electrical. I have spark and pulse at the coil but not at the injectors,I have power to them but noid light doesn't light up. I changed the fi-relay and also checked the pumps they will work when jumped but don't come on when turning the key. Also it tries to start if I spray starting fluid into the intake. I switched rsr with another with no results, I cleaned contacts on ballast resistor checked pins.....

Any help on what I'm missing would be great.

 

If it tries to start with ether - the engine speed sensor/ignition system is good.

What's the fuel pressure?

I don't have a diagram for a 91 - if a 94 is similiar this may be of some help.

The injectors are fed power through the ballast resister (20/15) from the injector relay (2/12) mounted near the left strut tower. If there is a bad connection (common cracked solder joint) in the relay there may not be enough power to fire the injectors. The control unit supplies ground to the injectors, all 4 at the same time. 12v for the injector relay comes directly from the battery. It's not fused. Check any small wires on the positive battery terminal and make sure they are connected tightly.

 

So I have power to the ballast resistor when key is on and 12v at both sides of the injector connector.....doesn't seem like I should have power on both sides of the connector.