e30 2.7 wont stop cranking, have to unplug the batt to stop it

[Conall456]

Hi everyone! I just put a replacement 2.7 in my 87 325e (5 speed), and iv been dealing with an issue where the starter motor would spin but the Bendix wouldn't push out to engage the flywheel.
I tried manually jumping the starter yesterday by hooking a batt to it directly and got it to turn over properly (it spun like before for a second and then the Bendix pushed out and engaged the flywheel, so im guessing it was just stuck or something and the direct supply of power freed it up). Today I put the battery back in the car after charging it and tried to start the car, it did the same thing where it spun up for a second, and then the Bendix pushed out and it turned over properly, but when I released the key to stop it from turning over it just kept going and I had to unplug the battery to get it to stop.
Has anyone seen this before? im so close and would love to finally get the starting system working properly.
Thank you!

[It's Soda Not Pop]

Your ignition switch could be bad (which normally the car wouldn't start or at least be difficult to start). I would also retrace everything that you unplugged when you did the swap. It could also be a stuck relay. Might be time to replace old relays and switches and whatnot.

[It's Soda Not Pop]

https://www.r3vlimited.com/board/forum/e30-technical-forums/e30-faq-and-diy/333798-diagnostics-tips-tricks-by-jim-levie-e30-jedi-master

[jbontke]

I remember trying to "southern engineer" the temp sensor wiring for the cold start injector and it causing a similar issue. I don't know if you are using the ETA engine harness or the I engine harness.

[D3R3K]

pull the starter relay and see if it is still cranking, to isloate the starter. I cant remember which relay it is but its one of the 3 under the black cover next to the strut tower. also the ignition switch can stick, try cylcing the key back and forth fast like 20 times and try again and see if it helps freeing the ignition switch up, hope this helps!