Odd problem: Z4M Stalling for no reason?

[funkdude]

Hi guys, I am encountering a strange problem and would be great if anyone can advice.

It has happened once or twice before but recently the problem is becoming increasingly persistence (It has occured 3 to 4 times within the last week)

My car stalls when I step down the clutch as the car is coming to a hault or coasting very slowly.

Has anyone ever come across this problem or has any suggestions as to why is this occuring? Does it has a more serious implications than simply stalling?

It is one of those problems where you cant just bring it to the dealer because it does not always happens so it is hard to test it out... I am due to go off to an EU road trip soon and would be keen to make sure my car is given the greenlight before I set off.


Many Thanks.

 

[enfield]

Very common. It depends on the fuel used. More EtOH = more starting problems. I use Shell V-Power and have no problems. Ethanol content of Shell V-Power is 0%. Last weekend I was in US and the problem started again because I filled up at a gas station on the Ohio Turnpike. Burned the off and now I am back to V-Power and am just dandy thinkyou!

 

[funkdude]

Many Thanks for your comments Enfield, It is good to hear that this is a common problem atleast. I also have an E55 AMG and I run it on normal unleaded aswell (Only use Shell for both cars) and this problem has never occured?

Does this have a larger - more serious / damaging implication on the car? Do I have to switch over to Super Unleaded or can i just keep using normal unleaded if the regular start up stalling isnt too much of a problem? Fuel price is way too expensive in the UK!

 

[Caddyshk]

Are you at least running the minimum required octane?

 

[mikedav]

Do I have to switch over to Super Unleaded or can i just keep using normal unleaded if the regular start up stalling isnt too much of a problem? Fuel price is way too expensive in the UK!

It shouldn't be down to using 95. I run my M on 95 because on both this and my previous M3 I noticed no discernable difference between running on standard or V-Power/Ultimate for prolonged periods. If there is a difference it's too minute to detect. I did the same tests with my old 330 Sport (M54 engine) and again, no difference at all. Only car I ever noticed it on was a remapped Golf GTI 2.0T which had been optimised to run only on higher RON fuel as part of the map...

Are you at least running the minimum required octane?

You can't not here, basic grade is 95-96RON, equivalent to 90-91 Octane. Our 'premium' fuels are V-Power / Ultimate / Tesco 99 RON and are 98-99RON, but at 123p a litre it's alot more than standard 95, around 114p a litre. You can get 102RON from some BP stations but it's 250p a litre LOL.

 

[funkdude]

hi mikedav, thanks for your comments. I too agree that 'premium' fuel does not make any difference. Given the price difference it really isnt worth it.

Mikedav so do you get the same start up problem as me with normal fuel? Is it really the fuel???

 

[mikedav]

Nope no problems at all....enfield mentioned ethanol content, I don't suppose you use mostly one brand from a certain station or anything?

 

[funkdude]

I have just contacted BMW UK and they have consulted their 'most senior technician' and aparently they have never heard of such problem. If it is as common as Enfield suggested then surely they would've know about this?

Mikedav yes I mainly go to 1 or 2 Shell stations both around my place. I only use Shell Unleaded tho and I would imagine that is already a quality bench mark?

 

[enfield]

When I picked up my car the SA told me that BMW does not recommend using gasoline with >10% ethanol content. Therefore, I go for the only gasoline available with 0% ethanol - I do not know what engine you have.... I was told that this was an issue for the S54 engine.

I would suggest that you run your tank to almost empty and try a different brand of gasoline. I did and it worked. Maybe it will work for you too.... Let us know what happened. You can always take the car to the Stealer and have them run tests to see why it stalls when cold.... It is not supposed to do that - even the Stealership would agree :lol:

 

[Dammmittt]

Just a tidbit for the US guys reading the thread...Shell V-Power along with all other commercial gasolines in the US are required by almost every state to contain at least 5-10% ethanol.

 

[WaZZZZman]

Just a tidbit for the US guys reading the thread...Shell V-Power along with all other commercial gasolines in the US are required by almost every state to contain at least 5-10% ethanol.

Wouldn’t they have to post that somewhere at the station? As I understand it here in Washington State, the oil comes directly from Alaska to the refinery in the northern part of the state and then to the stations.

 

[Dammmittt]

I think it depends on the state...here in new england its posted and theres no escape from the E, not all states require it, so maybe washington isn't one of them.

 

[Caddyshk]

Just a tidbit for the US guys reading the thread...Shell V-Power along with all other commercial gasolines in the US are required by almost every state to contain at least 5-10% ethanol.

In Ontario its % ethanol based on total pumped per station all grades - thats how Shell gets around it here.

 

[funkdude]

Hi guys, my stalling problem is still persistent so I thought I will post another message here to seek further opinions.

I have tried different types of petrol and still it has no improvement. From time to time my car still stalls when I have my clutch down coming to idle. Last time it happened was two days ago when I was coming to a stop in the middle of a busy cross road… bloody dangerous!

BMW took my car for a few days but cannot find any problems with it as it did not stall while they test drove it so there is nothing they can do..

Anyway after living with it for over half a year I think I have found the problem… I notice that the Z4 MC has a mechanism that revs the engine (to about 1000 - 1200 rpm) automatically when you push the clutch down when the car is travelling extremely slowly (or coming to idle). Effectively this is probably what keeps the engine running at very low speed / low revs.

In my case - from time to time my car will stall when this mechanism fails to work - whereby the rev is coming down to 0 rpm when the clutch is held down (neutral) so the engine cuts off.

My question is, does anyone know what is the term used for this mechanism? If I know what it is at least I can mention it to the dealer and they can check that out specifically…

Don’t know whether I have explained this clearly enough… please let me know if I am unclear and I will try to explain.

Thanks

 

[Curtis]

This may not cure your problem but the fuel test results and conclusions are interesting none the less. Testing was done using an M3 CSL.

http://www.thorneymotorsport.co.uk/tuning/Fuel_Test_Results_Update.shtml

 

[Andy]

Mainly use 95 in mine except when I'm fancying a hard B-Road thrash and feeling flush, have done 20k miles in 2years and it's not stalled once.

I would have thought there would be a fault code stored for a stall, amazed they can't find it. If you can find some way of reproducing it, like putting it under load in too high a gear or something.. that would be your best bet.

I would guess that crap fuel would lower the tolerance to these sort of things, but it shouldn't be happening at all. My salesman who drives a Z4M was amazed when i said mine was definitely a bit rougher on 95, but never to the point I'd moan about it.

 

[carl]

My question is, does anyone know what is the term used for this mechanism? If I know what it is at least I can mention it to the dealer and they can check that out specifically…

In the old carbureted days it used to be called an idle control valve.

 

[funkdude]

thanks guys... the idle control valve it is then..... i will bring it up next time I take the car to service... At the meantime lets hope I wont kill myself with this problem coming up at random times at dangerous junctions!