First of I wanted to state I in know way think this is related to the tune or ECU, I just wanted to see if anyone had any ideas one what to try to fix this issue.
I'm in the process of swapping a m52 into my 1992 325i, using an 95 m3 harness. Got the new to me motor, did all the gaskets, other than head and timing cover, got the sensors from a 93-95 that I needed, knock, cam, and coolant temp adapter. Moved over my crank sensor from my 92, as well as my ICV and CCV setup. Using pink top injectors, OBD1 fuel rail and m50 manifold, have tried both an 93-95 maf, and a 3.5 maf from a 540.
Started buy getting the motor in and not being able to start, first found I had be trying to pump fuel into the return line, as I swapped the lines that connect right buy the throttle body. Once I figured that out, I found that not having the TCM plugged into the chip, means it doesn't start. So I plugged that in then it started fine, but I get this surging idle, which you will see in the attached video, goes from 1200 to 3k. I have swapped ICVs, checked for vacuum leaks, and ran a peake research tool on it. The main code I'm getting is a Intake Air Temp, error, and a Control Supply Unit error. Now these could be to do with me testing and trying things when I was working to get it to idle correctly. Disconnecting TPS, or MAF, makes the issue much worse. Disconnecting crank sensor changes nothing. Disconnecting ICV seemed to make it just a bit worse. And as you'll see in the video, disconnecting the elbow just a bit to let in more air, past the MAF, makes it idle better, but still higher rpms, like 1500.
So it seems I'm running super rich. I haven't connected my wideband to test, but it seems to be the issue. So I'm looking for ideas here. I'm thinking of testing a new fuel rail and/or injectors with a new fuel pressure regulator, as I wonder if I broke it, pushing fuel into the wrong side of it. Also I wonder if maybe my crank sensor could do this, but doesn't seem likely.
Lastly two other issues that may or not be related, my 95 engine harness's x20 round connector is missing pins 1,2,3, and 9. Where my chassis side of that connector on my 92 325i (was an auto) is missing 1,2,9,10. So I'm not sure if that will cause any related issues, I'm doubting it, but I'd like to know what it effects. And lastly an relay back by the heater core and brake booster is making a noise like a relay flipping on and off.
Thanks for any help, I'm going to keep working on it, but any pointers would be great.
http://youtu.be/Ts8umJCAScQ