Cold start stutter and stalling

B

Babw

Member
Can someone give some insight into this annoying issue with my Z4M roadster?

It's my daily driver and pretty much every morning on the first crank the engine stutters and goes to stall before going back up to idle. Twice it has stalled completely. Those two times on the second attempt it starts without fault and when the engines warm it starts first time with no issues.

The car has 29k miles and is on 97 ron fuel (best I can get locally). It has a new battery within the last 1000 miles and has approximately 5k miles to an Insp 2. The starter seems to be cranking well.

To me it almost seems like a fuelling issue but I can't be sure. I remember no such issues with my old S54 M3.

What's the consensus? I'll post a video up tomorrow morning.
 
I've no answers but can confirm mine has started to do this recently. It hasn't actually stalled yet but there is a momentary stutter on cold start.
 
Not Z4MR specific but when my S3 did this (albeit on a turbocharged engine) it was the MAF. It had been knocked after installing a new TIP and stuttered on cold start but was OK when warm. Try unplugging the MAF to see if it helps (albeit only test for a short time) - if it starts fine, that's your issue.
 
As said MAF or idle control valve maybe? Also, the VANOS I believe sets the cams to the best position for cold starting I believe so possibly an issue there...
Has anyone changed the fuel filter on these cars? PITA to do apparently as its contained in the fuel tank apparently.
 
AndyBeech said:
Has anyone changed the fuel filter on these cars? PITA to do apparently as its contained in the fuel tank apparently.
Click to expand...
I was wondering about this, seems a ridiculous place to put it. I'd like to change mine, but positioning makes it practically impossible.
 
Had similar symptoms on my E46 Smg M3 when I got. It would be very intermittent though.

Not long after I got it I had an Insp 2 done, valve clearances and full vanos overhaul. Changed fuel filter too. Car was spot on then with a steady idle and smooth to drive when cold too.

One thing that's improved cold running even more is my remap I've had done accompanied with my Eventuri intake. It's very smooth now and a different car when cold too.

Shame I can't pinpoint what it was but after all of the above it's certainly sorted mine out apart from the odd kangaroo moments which these motors are renound for doing anyway.
 
Just to revive this thread and issue which still remain a little mysterious. I started the car this morning after 5 days of not being driven and it started before it even cranked fully once. Car has a quarter tank fuel, the coldest morning since I've bought it (April) and it's due an Insp 2 in 2.5K miles.

The only difference to normal is that I parked it further up the drive which is sloped towards the front of the car slightly more than normal.
 
I put another thread on about my problem ..........
I changed the front Lambda sensors for new units .....
all problems gone ........
 
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