TunerPro User Forum

I just swapped an M52B28 into my 1987 325is. It's using a Red Label 413 DME which is 3.3.1 I believe. It has Pink top injectors and an M50 Manifold and I purchased a 1995-1996 BMW M3 MAF Part No. 13621747155. The chip that was in the DME when I bought the setup seemed to have been the stock M50 chip that would have been in that DME (I assume the PO yanked the performance chip since she was just rich at idle and lumpy when I started her the first time). I rescaled the injector values to match the Pink Top injectors and the idle smoothed out beautifully... however... only when the MAF is unplugged (Alpha N). Once the MAF is plugged in it goes back to a surging idle and smells rich (I wish I added my wideband when I welded the exhaust but I didn't unfortunately). I scaled the MAF table down by using a multiplier of .8 and it idled a bit better but eventually stalled. Would anyone happen to know what the MAF table should be for this particular MAF?

I have also compared my MAF Cal kg/h table against a public base OEM bin for 95 e34 525i Manual with an M50 and they match so from that perspective they are valid however I know that is based on that particular setup and not mine.

Not sure whether this is one of those things that you really need a wide band and your particulars in order to figure it out... or whether someone has something that might get me in the ballpark because I know this type of setup was done many times before.

EDIT... I just looked and the MAF I purchased is the one for a 95 e34 525i... so I dont' get why she is not happy with it.

Final EDIT mods can delete this. I Reverted back to my original BIN and somehow all things are fine now and this MAF is the correct MAF for my Base BIN settings. Apologies for the confusion.

I used the OE 95 525i BIN and the setup should be perfect for the MAF and injectors. Issue I have now is when returning from higher revs back to an idle it loops 3-4 times and then settles in. I noticed that when my wife went to roll down the window at a steady idle it seems to bump into that loop again so I just re-ran another ground cable to the engine to see if that helps. Seems like when I leave her in gear and decel I can hear when decel kicks in and she doesn't loop at idle... however when I just pop the clutch from higher RPM's she loops at idle. Not sure if this has anything to do with a table setting but please suggest if you have any ideas. Thanks in advance.