528e starts but won't stay running (long)

Hello, this is kind of a long story but here goes.

I recently acquired a 1986 528e as a trade for some artwork. The car would not start at the time. Symptoms - car was running, then stopped. That's all the previous owner could tell me.

I ordered the Bentley publishing 5 series book. Waited 2 months to get it. Before the manual arrived, I decided it was the fuel pump and replaced it and the filter. I decided new spark plugs wouldn't hurt and did those. Then I replaced the main relay and the fuel pump relay. Still wouldn't start.

Received the manual and found out to check the speed and reference sensors. Checked them and found that the reference sensor was nearly cut in half. Found rubbing on some weird bracket that appears to hold nothing. Went to junkyard and pulled 2 sensors.

Installed, said my usual prayer and vroom - it started first try! Released key, died immediately. Thought - well it's been sitting for about 6 months, let it warm up a little and rev it. So the engine runs fine as long as the key is turned all the way forward (cranking/start position?). It idles, revs up sounds great. As soon as I release the key from all the way forward to the (run?) next position, it dies right away.

I looked through the Bentley manual, but couldn't find these symptoms described. Can anyone tell me a likely place to check? PLEASE HELP - if you can refer me to a post where this has been diagnosed or a page in the Bentley manual I will be quite grateful.

I don't think this will matter, but I'll mention it anyway. The air filter has been removed. I plan on installing a new filter and changing the oil as soon as I can get it to run on it's own.

Thank you for your time, and hopefully your help.

Eric

I had the same problem. Did the the same things, to no avail. It was caused by the fuel pressure being too high. Replaced the fuel pressure and solved the problem.
85 528e

its the ignition in the column, your instrument lighting doesnt light up in the accessory position either i bet