M54B30 issues.

[Ryann]

Thus far the e46 guys haven't been able to help- maybe the r3v 24v bunch can bring something to light.

I've been troubleshooting intermittent drivability issues in an '01 330i (AT,84k), symptoms as follows:

1. engine starts up fine, but intermittently idles like shit. revs smoothly/freely in park or neutral.
2. pulls away with the occasional stutter and is drivable cold with somewhat limited power.
3. once warm it bucks and stutters, will maintain a max speed of 15-20mph or so. throws misc. p1345-6-7-8 etc. codes "cyl. X misfire with fuel cutoff". was also once accompanied by a "bank 1 lean" code.
4. SOMETIMES, it will fire up and run/accelerate smoothly but with limited power, like it's towing a tent trailer. During this mode of failure a distinct whooshing sound can be heard from the tailpipe, kinda like the hose on a shop vac. No codes are thrown during this time.

What I've done:

-pulled all the plugs, nice and evenly golden brown.
-inspected all intake plumbing and IAC hoses for vacuum leaks
-replaced the FPR/fuel filter assy.
-energized fuel pump and verified system pressure
-removed MAF and checked for dirt/contamination
-unplugged MAF and noted changes in behavior

I am aware of vacuum leak issues on these engines, but under close inspection I don't see or hear anything. When I unplug the MAF the idle instantly improves but drivability is still poor, which is strange to me because in my experience MAF equipped cars don't typically run with it disconnected. Also, I attempted to perform the fuel pump volume test as described in the Bentley manual and the results were substantially below spec, but I'm not confident that the inline valve on my FPG isn't restrictive.

thoughts?

[bmwstephen]

there was an ignition coil recall for m54's in 2004. You might wanna check that.

[Ryann]

there was an ignition coil recall for m54's in 2004. You might wanna check that.

Misfire codes show up together in random groups when engine bucks/chugs/no power, then all disappear when symptoms shift to smooth/lack of power/exhaust whoosh. Seems unlikely that coil failure would appear this way. Also, the verbage "misfire with fuel cutoff" seems like a clue but I'm not sure what to make of it.

[JSWIFT]

"misfire with fuel cut-off" indicates a catalyst damaging misfire, meaning that you car has detected that a catalyst damaging combustion event is occurring and ultmately damaging the catalytic converters. As a solution, the DME does not fire the injector for that cylinder at that specific moment. I would replace the crank case vent valve and the 4 hoses associated with it, or at least visually inspect the oil return hose in particular. It is the one on the bottom of the ccvv that runs to the oil pan. It s notorious for tearing and causing massive vacuum leaks that in turn lead to the codes you are getting. Also, what are you scanning the car with?

[nrubenstein]

Did you check fuel pressure at idle, or under load? I had a friend's 330i that showed 3.5 bar at idle, but, well, a LOT less when I revved it.

[Ryann]

JSWIFT: I will inspect said crankcase vent system tomorrow, thanks. Scanning with a Snap On MT2500. It's software apparently doesn't support data screens for the MS 43.0 system so I can't see what's happening I/O-wise, only able to recover and clear codes.

nrubenstein: Good point. I was going to repeat the volume test tomorrow anyway so I think I'll tape my FPG to a wiper arm and take it for a test drive.

[jlevie]

The first two actions should be to run a crank case pressure check to see if the CCV has failed and to have a smoke test run on the intake. The symptoms described and the fault codes list are consistent with intake leaks.

[Ryann]

The symptoms described and the fault codes list are consistent with intake leaks.

This was my initial gut feeling, and the reason I took a hard look at the intake ductwork.

[Ryann]

Update: I performed a thorough inspection of the crankcase vent valve and all associated hoses. The hoses are in great shape including the oil drain back hose, which was nice and supple with no cracks or sludge inside. At one point I resolved to completely remove the intake manifold. I followed the Bentley procedure step by step until I got to the part that said "lift the manifold up and away from the head while disconnecting various hoses and electrical connectors". It felt as though I was trying to uproot a small tree. Anyway, I was running out of time and had to get things back together so I never had a chance to thoroughly inspect the manifold for cracks or get a better look at the rats nest under it. The owner is currently driving the car with the MAF disconnected because it is at least drivable. This issue is beginning to piss me off.

[dirtysix]

Suspect Vanos.

[JSWIFT]

Seriously doubt it is vanos related. Vanos failures on the m54 are typically subtle, slight power loss, slight reduction in fuel efficiency and/or light rattling from unit itself. Scanner is probably giving wrong code descriptions (factory level equipment i.e. DIS, or INPA). Ho many miles on the car? I am betting over 100k. If so, change plugs and connectors/coils for missing cylinders.

[dirtysix]

We had horrible loss of power with Vanos problems on a m52tu(essentially same as m54).

[Ryann]

Car has 74k on the clock. Why the hell would it be so much better with the MAF unplugged?