Weird driving and idling issues with MAF plugged in, OBD1 m52b28

[TeXJ]

First, checked multiple times for vacuum leaks and have just replaced the MAF for a second time.

OBD1 running the red label 413 DME

The car will rev hunt, and die, at times, when coming to a stop.

If I unplug the MAF, these symptoms pretty much disappear.

So I think it's either the wiring, the signal to the DME, or something along those lines that is causing this issue.

I bought the car swapped so I'm getting to go through all of this.

Any ideas on what to look for? Has anyone seen/heard of this and if so know of a place to start to look if not know a fix?

not sure if this matters, the car was also 5spd swapped to a g260.

[TeXJ]

looking for some info on the MAF and what the signals should be, voltage, to the DME.

Also, are there any other parameters that the MAF uses from other sensors?

[pazi88]

Is the ecu software modified for b28 engine? And do you have the b28 pink injectors. Could be just that the ecu is not up to the task, if it's not flashed to match the setup.

[Metallated]

I think sometimes the MAF sensor can get oily or dirty and can act weird, could be worth trying to clean it or swap in a known good one. I've heard of oiled cotton filters causing issues if over oiled.

[TeXJ]

Is the ecu software modified for b28 engine? And do you have the b28 pink injectors. Could be just that the ecu is not up to the task, if it's not flashed to match the setup.

stock DME red label 413
does have the pink top injectors.

Was told by other tuning companies that it shouldn't need a tune to run correctly. Now a tune can "wake it up" but the issues I'm having they said that it would fix that.

I was talking with a guy from Kassel Performance and he thought it could be the Fuel Pressure Regulator. Mine was disconnected from the vacuum line. I've since connected it.

A guy from Turner Motorsports stated that the tune wouldn't fix the issues I'm seeing.

I think sometimes the MAF sensor can get oily or dirty and can act weird, could be worth trying to clean it or swap in a known good one. I've heard of oiled cotton filters causing issues if over oiled.

I've replaced the MAF twice. Before replacing it the second time, I did clean it with MAF cleaner. No change in behavior.




Question:
Does the MAF signal going to the DME use signals from other sensors? So the DME gets the signal from the MAF and then the other sensor and then makes the Air/Fuel ratios needed.

I'm thinking maybe by me disconnecting the MAF that the DME goes to it's stored Air/Fuel tables and so it doesn't use the information sent from other sensors?

[TeXJ]

Took the car to a much more experienced BMW guru that has done these swaps a ton. He has gone ahead and swapped to an m50 intake, wiring harness, throttle body and deleted some of the legacy OBD2 sensors I had.

Basically completed the OBD1 swap.

Car runs much better now! Now I just need to get a chip for it.