Engine just shuts off while at a standstill in neutral

[Hornung418]

I'm unaware if there are differences between M52tu and M54 engines, but your issue is exactly that of my 328i. Coming to a stop in gear, the second I took it out of gear, the car shut off at the light. Sometimes I didn't even realize it was shut off. The solution wasn't apparent right away, but it took several weeks of driving like this to trip the code. I had a really hard time starting and often times it would put it self in safe mode.

Solution: Intake Camshaft Position Sensor. I was at 106k and was the first repair I had to perform. Easy 2 hour job with cleaning the intake tract.

Could be a wheel bearing issue. Wait for Dane to respond.

[kayger12]

CPS is definitely a suspect.

Also agree on a bad bearing being the source of your scraping sound.

If you can lift the rear of the car safely, try to rock the tire alternating pressure at the 3 and 9 o' clock positions.

If you have movement, you have a bad bearing.

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[GreenFrog]

Another point of info: while the car has trouble cranking from a cold start, when it's all warmed up and I park somewhere and come back, it cranks perfectly without any hesitation. Dunno if that helps or means anything, but just throwing it out there.

As for the bearing, my roommate thinks that could be the issue as well. What would cause the bearing to go bad? The sound came about around 3 days ago? I don't have any lifts or jack stands so I can't perform that test you mentioned.

Stupid Boston potholes.. they're so bad!

BTW, thank you guys so much for the quick responses and insight!

[aurelius]

OP: how many miles on your car?

Here's some info from the Beisan Systems (vanos repair) guy, copied from an E46 "Common Problems" document:

"Camshaft position sensors can fail and cause problems. They will usually
produce a code, but they might initially malfunction without producing a
code. A failing exhaust CPS will cause light performance problems. A failing
intake CPS can cause significant performance problems.
Aftermarket CPS sensors don't work. OEM CPS sensors are only available
through BMW. OEM CPS sensors have a BMW logo and this can be used to check
if a CPS sensor is OEM."

[kayger12]

Bearings are just a wear part.

They wear out and need replacing.

The potholes can accelerate the wear.

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[GreenFrog]

61k miles...

[aurelius]

I would do the intake CPS and, while you're in that area, VANOS rehab, plus idler & tensioner pulleys, and serpentine belt.

You're looking at a little over 400 bucks if you buy the parts at the right places and DIY. That's with the easier (tho more expensive) VANOS repair option.

Ask questions here if you need sources for the parts and or DIY info.

Your motor will run better and you'll get noticeably better mpg.

[GreenFrog]

How much would it cost to get that all replaced by a mechanic? I do have an aftermarket warranty so I'm wondering if that would be covered by it.

[danewilson77]

Got my car scanned -- no codes. The guy at Autozone said my car was running slightly rich..

Anyway, the problem of the engine just cutting out is getting worse (i.e. it's happening more frequently). It only happens when I'm coming to a stop in traffic (i.e. slowly) and as before, there's no jerky commotion. It's as if the fuel just cuts out.

I think it may be an issue with the fuel pump? When I'm in neutral at a standstill, the tachometer moves up and down ever so slightly (maybe 50-60 rpms). Also, the car has trouble cranking from a cold start.

I also have another issue where there is a strange scrapping sound coming from the rear left wheel while in motion. The sound gets faster as speed goes up, so it definitely seems to be related to the wheel. It almost sounds as if there's a piece of metal hitting something as the wheel rotates. Sometimes the sound will disappear, but it's there 80% of the time.

Any thoughts what could be wrong with my car? I'm going to take it to a mechanic soon anyway (if I can find some damn time off my job) but I want to have an idea with what I'm dealing with.

Have done the inspection I recommended above? It would be nice to rule out the easy stuff.

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[danewilson77]

How much would it cost to get that all replaced by a mechanic? I do have an aftermarket warranty so I'm wondering if that would be covered by it.

Mmm...I would just take it to BMW, have them figure put what's wrong, authorize no repairs, until you know how much. Doesn't sound like your gonna DIY any of it?

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