Took long enough, maybe it's tired

[Jean]

Going to try a different in-line fuel pump tomorrow and maybe my 89 325i intank pump if it fits....

[DCColegrove]

I assume you checked the basics: cap, rotor blah blah...? Actually checking the fuel pressure?

The pump in the tank (transfer pump) will cause similar symptoms at 1/2 tank of fuel if it's dead but will be fine on a ful tank.

Some of the L-jet M10 sneaky ones:

The AFMs and the TPSs in these take a shit and act in ways that just don't make sence.

And the granddady of them all:

There is a bunch of groung wires at the rear of the head (intake side) make sure that they are good. Some times they will break inside close to the lug and cause all kinds of havoc.

[Jean]

I'll check the ground connections and TPS as well with the AFM. Thanks!

[blunttech]

if its not the fuel pump, replace the main and fuel pump relays. I do more relays on e30s than pumps.

this is going to be it i bet. we just had the exact symptoms on my buddies m535 and after dicking around we just replaced the main and fuel pump relays and its as good as new

[Jean]

All grounds checked out ok. All hoses / intake boot ok as well.

AFM does have a dead spot in it's range, but I don't think that would cause it to die at idle, if anything it explains the "flat spot" in the 3-3.5k rpm range.

Replace the in-line fuel pump, and didn't make a difference. I did find that one of the shorter fuel hoses needed to be replaced, so I got a 50psi fuel hose from local parts store and replaced it as well just so that I don't have any fuel leaking in the future.

Replaced the fuel damper near the fpr with the plastic tube that bmw now ships instead of the damper (fuel damper wasn't clogged or anything) and replaced the fpr. That did it.

Took the car around the block, revs fine, idles fine as well. So far so good.

I'll look into replacing the AFM with a working one to get rid of the flat spot.

[Jean]

So I've been driving tor the last couple of days after changing the FPR and it's been fine. It actually almost feels like it drives a little better than it did before, so maybe it was on it's last legs and finally failed. I am curious though if the fuel vibration dampers are even needed at all? If you try and order one of those from bmw you'll get a plastic tube instead...