Cutting out

[Rodddimus]

Just wondering before i start investigating further if anyone has had the same issue before

I have a 350i - and when the car is hot or running for a while every now and then it will cut out when coming to a stop. So say im approaching traffic lights and i put clutch in and on the brakes as the car comes to a stop its like it doesn't catch the tickover enough and it will stall. Starts straight back up absolutely fine

things that make it worse
-Turning so for example to park on my drive i reverse on so when i come to a stop in my street im turning as i do so the my car has PAS so feels like the extra load on the engine brings it on

-stopping from a faster speed, slow gentle stops dont trigger it but a situation in which the revs dip from a higher speed seem to make it happen more often

-if when stopping i blip the throttle again after the blip the revs will dip and go too low and it will cut out

Never cuts out on tickover even in traffic, doesnt always cut out either its only happened say 4-5 times in 1600 miles - my first couple of thoughts were maybe either running a bit lean or some form of air supply issue.

The only other symptom is once the car is hot and its stopped if you simply start it, it can cut out, if you start it and give it a blast of revs after about 3-5 seconds of moderate revs therein its fine and running as normal again but had attributed that to fuel soak not sure if the issues are linked

Edited by Rodddimus on Tuesday 1st November 09:29

[ElvisWedgeman]

Sounds like an air leak in the engine to me and perhaps cleaning out the plenum intake and resetting the engine revs. Possible ignition module failure but unlikely as it starts up easily after stalling.

[adam quantrill]

What is the usual hot idle rpm?

[mark387mw]

I don’t suppose you have one of these fitted? Caused similar problems on my car as it built up resistance as the part deteriorated.

[Pumpkin123]

Got to admit I had similar symptoms on mine and I used to have to run with a tickover of 1200 to stop it conking out, weirdly it turned out to be the timing was out. Stupidly I set the timing to the timing marks on the crank pulley but later realized these were 4.5degrees out - what's that all about. Guessing the problem could be lots of things but I would have thought timing/air leaks might be a good place to start.... Good luck

[Rodddimus]

Its done it 3 times today after saying it doesnt happen often haha

hot idle is 1000rpm

I dont have a device like in the picture show fitted

I havent checked the timing or anything at the moment tbf so might be a place to start along with air supplies

[adam quantrill]

Only 4.5 degrees? On mine the crank timing marks were more like 10-15 degrees out, I had to dial in TDC and stick another graticule onto the pulley.

1000rpm should be plenty, for a standard camshaft, some of the trick ones require higher though.

Random cutting out at idle can be a pain to diagnose, I had some cutting out issues from a rev limiter before, and other things over the years such as the ignition amplifier, but I put in telltales on the ignition primary in the form of LEDs that I could see though the windscreen, to help catch it. The LEDs would show the pulses and were trapped by the trailing edge of the bonnet. However since the problem was found, I removed them.

[350zwelgje]

As Adam said:
- Idle at 1000rpm should be enough. I set it at 1000rpm to ensure the oil pressure stays up at idle when warm...
- Check if TDC is in line with the crank pulley, mine checked out ok.
- Run at 9degrees with 98ron myself and have no issues

Coolant temperature sensor (besides ignition, fuel, ECU, etc) has caused not running at idle (due to overfuelling), so perhaps worth a look.
The ECU has been resoldered, before that time it would only idle...., throttle would kill it.

Rob