Help fixing my engine stumble

[bshade]

Hello guys,

I am looking for some help with my 87 325is. I had a bad flapper door mass on it and replaced it with split second 3” maff, now the problem I am having I actually had before replacing the maff thinking that it was the stock maff causing the problem. What happens is around 2000 to 3000 RPM I get a had stumble that when looking at the wide band O2 it shows the car leaning out. The fact that the car leans out tell me its not getting fuel. So my first step was to replace the fuel pressure regulator, I put in the Bavarian Autosport adjustable rising rate fuel pressure reg and tried to make adjustments to that. I got it adjusted so that at idle I am just a little on the rich side. But I still get the same breaking up, and in some cases even worse. So could this be another problem? Or is my adjustable reg not adjusted? I am open to anything right now I just want to get the car driving and a little reliable again. I had it down fro the past 6 months putting all new suspension and breaks on it and want to drive it so bad but don’t want to hurt the engine driving it when its not running right. If you need any other information let me know I will do whatever I can to help you help me.

Thanks in advance for the help,

Brad Espenshade

[abepark]

I've heard if your running stock ECU a RR FPR will toally fuck with it and it won't drive good at all because it won't ever go into closed loop. If you use aftermarket ECU you can tell the ecu fuel pressure at certain RPM's.

try going back to a working stock FPR and hunt the problem with that.

[jlevie]

I am open to anything right now I just want to get the car driving and a little reliable again.

If that's the case, ditch the "split second 3” maff" and adjustable FPR. Replace them with a tested (see http://frwilk.com/944dme/afm.htm) stock AFM/airbox and an OE FPR. If the problem persists you'll have to look elsewhere for the cause.

[SpecM]

If that's the case, ditch the "split second 3” maff" and adjustable FPR. Replace them with a tested (see http://frwilk.com/944dme/afm.htm) stock AFM/airbox and an OE FPR. If the problem persists you'll have to look elsewhere for the cause.

+1 yep, isolate the problem(s), then modify.