2004 E46 330Ci auto (M54) stalling and hesitation when warm

[Funk]

A couple of weeks ago my 330 started misbehaving, but only when restarted from warm. From a cold start it drove fine but when left for an hour or so and then driven again, it was stalling or hesitating when pulling away and felt down on power. It hadn't generated any codes or CEL. My local garage did a smoke test which revealed no leaks and suggested that in light of no other clues, we started with the cheapest option of the fuel filter. I didn't know if it had ever been changed so it wouldn't be a bad idea to do that. The car seemed to drive OK for a while but thinking back they were mostly cold journeys.

However a week later the car misbehaved again and recorded a "P0340 - Camshaft Position Sensor A Circuit Bank 1" so we replaced both cam position sensors. This seemed to solve the issue and the car was much improved in general on the road - smoother and fuel economy has improved too. But after driving home tonight I popped in to see a friend and stayed for a couple of hours. Getting back in the car, the gremlins seem to have returned and the car once again had that slight dip of the revs/hesitation when going from brake to accelerator and stalled twice. Disconnecting the MAF doesn't make any difference at idle (when my E36's MAF was shot, it resulted in a rough-as-aholes idle when connected which disappeared when disconnected) so I don't think it's that.

Here's a video of what the car was doing a week ago before the cam position sensors were changed - it's more extreme and pronounced that what it was doing tonight though: https://www.youtube.com/watch?v=AvZKbr5T92Y (please ignore the crap audio quality, the car sounds fine in person!).

What's odd is that the car starts fine, idles perfectly and doesn't have any stuttering or juddering through the rev range although it did feel slightly down on power again tonight, almost like it's reluctant to kick down a gear. There were no codes stored tonight when I got home.

Any ideas on what else might be causing this? It's really starting to frustrate me and I'd appreciate any guidance or thoughts. I have noticed that it seems to be losing a little coolant if that's of any relevance? Most of the cooling system was replaced earlier this year so I'll be pissed if that's not right now too...

[Lagerlout]

For me this is an engine sensor issue of some sort. I would be leaning towards crank position sensor. You need someone who is good with a logging multimeter or scope to take a look at it. It could also be a IACV fault or MAP sensor fault. Check the wiring to your sensors and have a very, very careful look to see if you have any wiring where it may have worn through the insulation. I've seen faults like this caused by exposed wires grounding out intermittently.

[Funk]

Thanks Lagerlout, I'll keep your points in mind when I drop the car in at the garage tomorrow for them to take a look.

I think this will only accelerate my aforementioned itching for a V8 of some sort; I've never really gelled with this car, even more so now I'm having to reluctantly fork out or repairs to it. £470 in the last month and it's clearly not fixed yet...

It's a bit of a shame as it's one of my favourite shape 3-series and overall not a bad place to be. It's just never engaged me the same way my E36 did.

Edited by Funk on Monday 27th November 00:21

[Matt_N]

Is it using any more oil that normal?

What state is the CCV in, quite common for them to get gunked up and increase oil consumption.

Is the DISA valve rattling?

Spark plugs last changed?

Could be worth getting the coolant system pressure tested if it's using coolant, it's not massively common but M54 have been known to suffer head gasket failure.

[Funk]

Matt_N said:

Is it using any more oil that normal?

What state is the CCV in, quite common for them to get gunked up and increase oil consumption.

Is the DISA valve rattling?

Spark plugs last changed?

Could be worth getting the coolant system pressure tested if it's using coolant, it's not massively common but M54 have been known to suffer head gasket failure.

Haven't noticed any particular increase in oil consumption but I'll get the garage to check the CCV. Not noticed any rattle from the DISA valve and the spark plugs were done just before I purchased the car a year ago (or so I'm told).

I'll add the CCV and DISA valve to the things I get the garage to investigate though. What's strange is that from cold, such as this morning, the car drives perfectly so I'm not sure it's likely to be HGF?

[Matt_N]

Just thinking as it's an auto could it be leaking from the transmission cooler?

[Funk]

I'm dropping it into the garage at lunchtime so will mention the coolant side of things too as it may be helpful, I appreciate your input!

[Matt_N]

No probs, hope it gets sorted.

[geeks]

I know a couple of good specialists depending on where you are based if your garage can't help I will point you their way! (One is Essex based and the other is Salisbury)

[njw1]

Were the cam sensors replaced with genuine items?

[Funk]

geeks said:

I know a couple of good specialists depending on where you are based if your garage can't help I will point you their way! (One is Essex based and the other is Salisbury)

Cheers, I'm Sussex coast so a bit far away unfortunately...

njw1 said:

Were the cam sensors replaced with genuine items?

Yes they were - at the garage's recommendation too, as pattern parts can tend to be unreliable.

[Matt_N]

Did you have any joy Funk?

[Funk]

Car was in yesterday, they've cleared out a load of codes and we'll wait to see what comes back. Found the source of the coolant loss though; the water pump is leaking slightly and the spindle is flicking it around the engine bay. That's been changed today along with any belts that need doing too as they'd need to come off for the water pump anyway.

[stevewak]

Funk said:

Car was in yesterday, they've cleared out a load of codes and we'll wait to see what comes back. Found the source of the coolant loss though; the water pump is leaking slightly and the spindle is flicking it around the engine bay. That's been changed today along with any belts that need doing too as they'd need to come off for the water pump anyway.

Get the idler pulley done. Mine failed and I think BMW has a better one now.

[Funk]

stevewak said:

Funk said:

Car was in yesterday, they've cleared out a load of codes and we'll wait to see what comes back. Found the source of the coolant loss though; the water pump is leaking slightly and the spindle is flicking it around the engine bay. That's been changed today along with any belts that need doing too as they'd need to come off for the water pump anyway.

Get the idler pulley done. Mine failed and I think BMW has a better one now.

I did suggest this too but they said there was nothing wrong with the existing one and to leave it be as there was no play or noise from it. To be honest, it's unusual to have somewhere say that something doesn't need to be done!

[E46330]

My e46 330ci has just started playing up with the same problem, did you ever get to the bottom of it?

Cheers