Miller MAF and chip upsetting 325is OBC13

[Giddyup58]

Does anyone have a solution for my problem?
I just fitted a Gen 3 Miller MAF and chip to my E30 325is, and now the OBC is showing the fault code PPPP except for time and date.
PPPP, according to the Bentley manual, is the code that a wiring problem has been detected.
The install calls for the cutting of the White/Grey wire (pin 12) in the ECU plug and splicing it into the Red/Blue (pin 37).
I tried to find where the White /Grey goes, but no luck...

[Giddyup58]

You are quite correct. Pin 12 is no longer connected to anything, and the grey/white coming from the engine bay is spliced into the red/blue.
The ECU is fine and the car runs smoother and is a bit more responsive down low and feels that it has more urge up top.
I have tried 3 different chips in it, settling for a Dinan, and it went well, but now goes even better, but for a bit of hunting and stalling on cold start.
I ran it up on the dyno before the conversion and when I sort out an air filter, I will get an "after" reading.

Can't see how fitting the MAF would have caused the OBC to develop it's current problem, because as you have explained, the grey/white wire has no impact whatever on it.

Perhaps I disturbed something when I did the ECU modification, but there's nothing there to disturb... When I retrofitted the OBC, I left the alarm computer (?) off, so there is no wiring even close to the ECU...

Perhaps if I disconnect the battery again, it will reboot and give a better result?

If that doesn't work, I just may have to do as you suggest, and get another OBC and try that.

The joys of playing with 30yr old cars!!

[Speedtouch]

http://forums.pelicanparts.com/101-proj ... -pppp.html

[HairyScreech]

That's a really horrible way to get power to the maf considering thefe are 3 main relays only inches from the maf.

Another thing that can happen is the capacitor on the board can die and then the unit is unable to I terpret any incoming signals from the dash, date and time work ok but nothing else will. Mine gave no error code but did not show any data, others have said it had other symptoms, all depends what it does to the printed circuit when it blows.

[Giddyup58]

Hi all.
Problem solved.
Did the re-set... Worked a treat.
Thanks for your help.

[Speedtouch]

Glad it worked for you.