BMW Info Needed

[chuck schultz]

A neighbor has a barn-find '79 528i that looks pretty solid, but needs some work. (I finally stopped to ask if he needed it hauled away. . .) Most notably, it needs something, maybe an engine computer, that should be mounted on the passenger-side inside fender, and has two wires going to it, from the coil, I think. Unfortunately, he doesn't know what he's missing, so he doesn't know what to ask for.

Any ideas?

[e30Racer]

realoem.com has tons of diagrams for every BMW. He might be able to figure out what he's missing on there

[zukitek]

The only thing that comes to mind might be a ballast resistor? I have no idea whether BMW used them or not but typically ( on most cars of that era with a external coil)they had 2 wires ,were made of ceramic,and wre used as a voltage dropping device.

The again I could be way off.

[chuck schultz]

I remember a bad resistor on one of my son's cars (might've been a pre-Civic Honda.) It would start, but would stop running when you released the key from start to run. We shorted out the resistor, and it kept running. I don't remember if we ever replaced the item, or if we just left in the jumper.

[zukitek]

Yup exactly. Older coils were not designed to be able to run off of full battery voltage but they did require a full battery voltage start up and then the resistor would take over when you released the key to run . Thats what a ballast resistor was for .

There again Im not sure if it applies. I tried to look on my online mechanical manual ...Mitchell ondemand.... but it doesnt cover that far back at this point . Typically they only have good coverage 15 years old or newer. Fascists...who are they calling old??