e30 318 m20 swap issues

[baldwindoug17]

hey. so new to this forum and i was just looking to see if anyone could possibly provide a little insight for me or just tell me i over looked something small.

so i have a 85 318i. m10 motor locked up a couple of months ago so i found a complete 86 325e with an m20b27 in it. car was running but had a wrist pin hanging on the piston. also all rotted out or i wouldn't have even swapped it. went through and made the jumper harness from the jetronic to the motoronic 1.1 connector and would not start. i found after a couple of hours of digging into it that the black signal wire on the coil was shorting to ground and went away when i unplugged the ecm. pin tested the ecm and found that was the problem. ordered another used ecm and opened both of them up when i got it. they both looked the same on the boards. not burnt but a brownish area on the board spreading across multiple different paths. installed the new ecm and the short went away. car started no problem and ran for about 15 min with no issue. i was bleeding and found the gasket on the throttle body leaking. shut it down swapped throttle body and continued on with my way. (i have another complete engine with all the sensors)

so the next day i ran into the problem im facing now. started the car up and it fan fine for a couple of min. jumped to 3k and was bouncing from 3k to 1200 rpm. also noticed when i give it gas it bogs down.

so i pretty much did a piston out rebuild on it. the pipes i have are cut right after the 02 sensor because i have not had time to fab up pipes for it yet and ive swapped numerous parts trying to figure this out. swapped mass airflow throttle position and idle control valve. fuel psi is running 33psi and when it bounces it goes as low to 29psi. if i remove vacuum from the regulator its constantly 30. the injector pulse is matching the rpms and i can hear all of them firing with a scope. new plugs wires cap rotor. timing belt is new. also have no vacuum leak. coolant temp sensors seem to be ok to. everything is where it needs to be out of what im seeing.

tomorrow im going to resistance and current check every wire i possibly can and try to think of a way to test the speed reference and tdc sensor but if i come up with an answer or if you think of anything to help feel free to post a comment. any help on a direction to look at would be appreciated. thanks for reading.

[superj]

The 325e harness plugs into the 318 body without a jumper. And you have to plug a wire by the ecu into another wire but there is no jumper harness needed, its plug and play.

I think those sensors can be checked using a multimeter though, the ones in the trans. Just search in this forum for what the specs are, it will show up. I don't know off the top of my head

[Johnsortega]

First time on this
Q? I have a swap as well can’t get started

What Ecu should be used

[msservices]

Something about your fuel pressure readings didn’t seem right to me. You’re saying that with the vacuum line disconnected you are at 30 but with the vacuum line connected you’re at 33 ? I think the readings are all too low anyway?