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Discussion Starter #1
Hi all, my 2007 mini Cooper has started stalling when its warm. It drives perfect all the time except when you come to a stop when warm. It never throws up any fault codes or MIL light.The idle struggles and then it stalls, it always starts up straight away. It doesnt ever struggle to start hot or cold. Ive cleaned the MAP and the Vanos solenoids, all the live data looks good on my code reader. Anyone have any idea..? Thanks in advance.
 

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have seen failed vanos return spring and can shaft free float so when change revs from throttle to no throttle can wind the camshaft and stall the engine,, need a diagnostics tool to live data it see what the vanos position are when it does it,
 

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Discussion Starter #3
I put 12v to the dolenoidd and they worked ok, ive got 2 2nd hand vanos solenoids im gonna try just to see. Thanks
 

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Discussion Starter #4
Anyone think it could be timing chain tensioner, a bit more give when its warm. Its not got any other sympoms, i just dont want to blindly replace sensor after sensor.....TIA
 

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Mini Cooper S 2004 54 plate
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Hall effect switch somewhere? I’ve had these fail on cars and bikes, stop when warm work when it’s cooled down a bit.
 

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2008 Mini Cooper S hatchback,Automatic,Mello Yellow
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Hall effect switch somewhere? I’ve had these fail on cars and bikes, stop when warm work when it’s cooled down a bit.
I don't think there is hall effect in that there is a new steering system vs. the olsteering of Generation 1
mini coopers.
I would have to know specifics. like when the car was serviced for oil,coolant.
I would have to know which engine as the they vary in the non S 2007
is it the
N12B16A
or the
W10b16a
engine?
If it is the N12 I would venture to say. That it can be caused by alot of things in that engine you have MAF sensor that could be gummed up. You have the volume controlled oil pump. There were threads here not that long ago on the forum about that deal.
It's all a shot in the dark without a code. or at least a video of whats going on.
My opinion at this point is oil pump. because despite values given to the computer and nominal tolerances. The engine needs oil to function on a raw metal on metal fashion. This thread mentioned it being warm and doing this.
Of course it could be the back draft of air coming into the flex pipe because that is leaking which is also a known problem with the N12.
With no information given a symptom that is sketchy. It could be the air filter.
would need a little more to go on.
 

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Discussion Starter #7
Thanks for your help. Its the one without a MAF, its just been serviced with fresh plugs, oil and filters. Ive cleaned the MAP, or TMAP on this engine. The atmospheric pressure and temp all look good on the live data. The car runs superb when driving, its just the stalling and irratic idle when warm thats bizarre.
 

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Mini Paceman Cooper D MY2014
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Hall effect switch somewhere? I’ve had these fail on cars and bikes, stop when warm work when it’s cooled down a bit.
It's a good call, items such as a crank or can position sensors but they usually fail when they get warm then won't start at all until cooled down sufficiently but worth noting such components don't throw DTC's.

The OP describes it starting back up immediately with a rough idle. On vehicles I've worked on the past with similar it was the idle air control valve. Does the OP's car have one?

To the OP Lowline is this Video of any use?
 

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Discussion Starter #9
Thanks, it doesnt have and idle control valve, thats were I would have started too, ghat and the MAF, but its doesnt have one of those either..! Ive checked the PCV and the diaphragm looks good. Im thinking maybe an air leak somewhere... that sounds like fun trying to find that.😀
 

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Discussion Starter #10
UPDATE
Went big today and took the inlet manifold off, cleaned all tje throttle body and checked for carbon build up on the valves. All looked good. Took the timing chain tensioner out and it was very weak, it split when I got it out. New manifold seals arriving tomorrow so thats it for tonight. Ill report back tomorrow
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2008 Mini Cooper S hatchback,Automatic,Mello Yellow
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Heck yea! all that looks real good. Never seen a N12 intake port up close like that before. The N14 has a waffle scoring going on, more than likely to prevent condensation accumulation(so it beads).
Cleaning the Vanos Solenoid is no where near as good as replacing with a updated one. The Updated ones have Screen protecting the internals from damage.
Does it have the quote un quote "Death rattle". Or severe ticking going on?
 

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Discussion Starter #12
Hi thanks, its not got any death rattle, but then again it never had which is surprising when I looked how weak the tensioner was.
UPDATE: After all the cleaning all the above and changing the tensioner I took it for a good run and it drove perfectly, this morning it ran OK too but this afternoon the stalling started again, it will idle on its own but the then the revs start to rise to about 1300+ ( probably the engine management trying to stop it stalling again) I'm as a bit of a loss now without starting to buy random sensors and keeping my fingers crossed. All live data appears OK and still no EML.
 

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Mini Paceman Cooper D MY2014
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It will idle on its own but the then the revs start to rise to about 1300+ ( probably the engine management trying to stop it stalling again)
You said previously that you were searching for an air leak....

The symptoms you describe in your last post sound like either a vacuum leak of inlet air leak...my go to with air leaks is carb cleaner, carefully applied,without setting oneself a!ight, at key intake joints along with vacuum lines and junctions. This should get you a momentary stumble or rise in revs if you hit the target.
 

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2008 Mini Cooper S hatchback,Automatic,Mello Yellow
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I would change the fuel filter at 50 thousand miles the fuel filter gets completely cover in soot. It's really something else to look at. Considering other fuel filters stay so clean and rarely need servicing.
It feels very rewarding if anything else.
Sometimes stalling can be related to bad gasoline. Or water in the tank. Never let a car get under a quarter of a tank of gas if it has fuel injection. It can do a number on the fuel pump.
 

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Mini Paceman Cooper D MY2014
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have seen failed vanos return spring and can shaft free float so when change revs from throttle to no throttle can wind the camshaft and stall the engine,, need a diagnostics tool to live data it see what the vanos position are when it does it,
Hello Mike

That's interesting.Are you saying that a weak Vanos return spring allows full lift of the cam, thus opening up valves too far at the wrong moment making a mess of the air to fuel ratio which in turn causes the stumble?

If so is there any other way of diagnosing that if you don't have a live data reader ? I'm assuming a timing light and scribing your own timing marks at the crankshaft would be of no use as It's camshaft timing related?
 

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Discussion Starter #16
I tried swapping the vanos solenoids and MAP sensor with some off another car and its still the same. I decided give the engine a flush and change the oil and filter so I can rule that out. Ive still got the same problem but still no fault codes. Ive got a decent code reader and can see live data no problem. Im not really sure what the vanos reading should be so dont know if its correct or not. Ive got good coolant and intake air temperarures but a strange set of temperatures which I think must not be supported on the mini but are trying to be read by my reader.
280425
 

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Mini Paceman Cooper D MY2014
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Is that IAT figure not suspect ? My own non Mini car shows around 5 degrees less than ambient when car fully warmed and on the move.

Also, with regard the DME inside temp, could there be a fault with wiring, i.e. chaffed & shorting on a heat shield or internal processor fault ( but surely a DTC would exist?)

If it was me, I would get the codes read by a machine capable to fully do so, either purchasing one if the car is a long term investment or paying for a diagnostic service.
 

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Discussion Starter #18
Thanks for your reply, when I go to actual live the intake temps and coolant temps are all correct. I think these is just a values not supported by the car, unless anyone knows anything else.. My diagnostic is a good one its a Creader VIII
 

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Mini Paceman Cooper D MY2014
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Thanks for your reply, when I go to actual live the intake temps and coolant temps are all correct. I think these is just a values not supported by the car, unless anyone knows anything else.. My diagnostic is a good one its a Creader VIII
A what if - could those erroneous temp readings conflict with what the sensors are actually reading?
 

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-6 degrees on the iat would do it for sure, also timing chain tensioner is very old one can tell so chain will be bad for sure , just because they dont rattle dont mean not stretched and giving issues as will slap around and hurt tensioner and top guide and also inlet vanos sprocket gets a kicking as well ie breaks the return spring inside and causes free wheel
 
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