Only runs correct when no MAF is plugged in?!

[fishhouse4]

Originally Posted by Overboost

What MAF sensor brand did you replace it with? There are a lot of horror stories out there with cheap MAF sensors. When you unplug the sensor, the DME reverts to Alpha N mapping (throttle vs. RPM). Plugged in it uses the MAF values. If the MAF was Genuine BMW or OEM then I would check connections at both ends (MAF and DME) and look for any physical damage to hoses or orings.

I will check the connections on both ends.

The only two ideas my tech had was a new engine wiring harness (which would address those connections you just mentioned) OR a new DME. Both are stupid expensive...

Ok, help me here...this is what I don't get about the wiring/connection possibility:

It's just a wire, correct? It simply transmits the signal from point A (MAF) to point B (DME). Like... all or nothing, I would assume. So if the wiring or connections were damaged, then the signal wouldn't go to the DME. Which would be the exact same as having the MAF unplugged. So I would think in that case you would not get MAF signals to the DME regardless of if it was plugged in or not.

Or are you suggesting that the wiring/connections could be damaged in a way that could somehow degrade or corrupt the signal from the MAF??