u/micholasnitchell

I’m chasing some electrical issues on my 1990 320 auto.. and I’ve found this plug next to the DME with nothing connected to it. Any ideas anyone?

Long story short I’m trying to investigate/diagnose a running issue, and I’m trying to get to the bottom of why my fuel rail loom seems to be different to everyone else. Instead of the blue plug going to the blue temp sensor, mine goes into another plug half way along the fuel rail.. and then there’s a third black plug that goes into the blue temp sensor. Every other M20 engine bay I’ve looked at does not have this. Blue plug goes to blue sensor etc. Has anyone else got a facelift 320 with an auto gearbox (not sure if that makes a difference) that can check? Or maybe someone knows what that orangey looking plug does and where it goes. Hoping someone can tell me before I start stripping the exhaust manifold to investigate.

Okay so I’ve had this car since 2009 and have worked on it extensively over the years. However the last 3 years I’ve been experiencing an issue that me and a number of specialists just cannot get to the bottom of! Rather than throw more parts at it I was hoping there’s an M20 master tech on here. So basically every year out of nowhere, the car will idle like s**t, and cut out as soon as you rev it and let the revs come down. Seems to get better once it warms up, and is resolved by adjusting the AFM while connected to a fume analyser. I only use the car during the summer months and at some stage of the season this will happen. Once AFM is adjusted there’s a still a slight bit of idle hunting at traffic lights but not enough to move the rev gauge. Things it’s not; AFM, idle control valve, valve clearances, air leak, spark plugs, ECU, fuel pump, fuel filter, relays. Probably more but I can’t remember. This past month the car has been driving brilliantly.. then bang get in it this morning and the issue is back for 2026.