Mini keeps misfiring- Mini/BMW can’t fix it. Any Ideas?

[CJ1]

Hi All,
I have a 2015 Mini Cooper S. Owned it 10 months and covered 10000 miles. Bought it with 65000 miles with a Full Mini Approved Used Warranty.

Car has a very annoying issue. As soon as the engine starts the engine idles poorly, It shudders and splutters (misfires?). There’s no physical movement on the RPM Gauge but you feel it shudder the entire car. It also has the same idle issue once warmed up but less pronounced. Car has been returned to Mini 5 times now, after a lot of software updates and ECU re programming the issue has got better when warm (smoother idle) but still has this cold start issue.

No Codes stored on ECU. Always run on Momentum 99. Recently had Spark Plugs changed. Car drives and pulls fabulously (no issues whilst under load). Still feels powerful.

Really have no idea what it could be... does this sound like a Coil Pack Issue maybe? Any advice appreciated.

[Krikkit]

Have the Mini techs been able to replicate it in their care?

A live logging session with as many sensors as possible and injector PWM etc would perhaps start giving a clue...

[Sardonicus]

Krikkit said:

Have the Mini techs been able to replicate it in their care?

A live logging session with as many sensors as possible and injector PWM etc would perhaps start giving a clue...

This < definitely a job for the scope with some data acquisition in order under no circumstances let someone fire the parts cannon on this one faulty fuel inj's woes are not unheard of on this engine not always throwing DTC /fault codes just for example

[CJ1]

Yes they acknowledged the issue, the very first time i brought it into them they suggested it could be an injector issue. They were going to investigate which one it was and choose whether to replace them all or just one. Unfortunately they decided it wasn’t the injectors as they couldn’t prove to Mini HQ it was and they couldn’t claim back on the warranty.... so just did an update....

Next step is taking it to a knowledgeable specialist I think. BMW/Mini Dealers haven’t been much help so far!

[stevieturbo]

Bit vague here.

And you havent given any details at all about any proper diagnostic checks that may have been done already.

Like even you suggesting a coilpack....surely this has been investigated at an early stage already ?

[CJ1]

stevieturbo said:

Bit vague here.

And you havent given any details at all about any proper diagnostic checks that may have been done already.

Like even you suggesting a coilpack....surely this has been investigated at an early stage already ?

Apologies for being vague, Unfortunately the Mini garage are the ones being vague with me. They admitted they did a Misfire test, nothing came up, and an injector test which once again showed nothing. Scanned the ECU and once again nothing.

It’s proving very difficult to diagnose it. I suggested the Coil Packs but they assured me they were fine (never been changed in 75000 miles).

Another thing I have noticed is on start up idle there’s a very strong smell of fuel...?

[E-bmw]

CJ1 said:

on start up idle there’s a very strong smell of fuel...?

From where?

[CJ1]

The Exhaust, almost as though it’s running too rich..

[E-bmw]

Something isn't right with what you are saying.

It is shuddering/spluttering at idle - but the revs don't change & there are no "misfire" events stored.

If it was misfiring there would be.

[CJ1]

E-bmw said:

Something isn't right with what you are saying.

It is shuddering/spluttering at idle - but the revs don't change & there are no "misfire" events stored.

If it was misfiring there would be.

Well that’s exactly what is happening, the engine shudders and splutters causing the car to shake but there’s no fault codes stored and it doesn’t show up on the Mini dealers “misfire” system. Even though the technician has sat in the car with me and felt it for himself...

Anyways, Ive found a good BMW Mini specialist that can hopefully get to the bottom of the issue...

[stevieturbo]

CJ1 said:

Apologies for being vague, Unfortunately the Mini garage are the ones being vague with me. They admitted they did a Misfire test, nothing came up, and an injector test which once again showed nothing. Scanned the ECU and once again nothing.

It’s proving very difficult to diagnose it. I suggested the Coil Packs but they assured me they were fine (never been changed in 75000 miles).

Another thing I have noticed is on start up idle there’s a very strong smell of fuel...?

So basically the retards in the dealer have plugged it in..and it says no fault. So they're clueless.

Dealers never fail to amaze.

Like really...a misfire test ? an injector test ? Yet by sounds of things these have not been removed from the engine and need tested ?

Taking the car elsewhere is a sensible approach, as from what has been stated....the dealer garage people must be retards.

[CJ1]

stevieturbo said:

So basically the retards in the dealer have plugged it in..and it says no fault. So they're clueless.

Dealers never fail to amaze.

Like really...a misfire test ? an injector test ? Yet by sounds of things these have not been removed from the engine and need tested ?

Taking the car elsewhere is a sensible approach, as from what has been stated....the dealer garage people must be retards.

I fully agree with you, the Approved Used Mini Warranty has been absolutely useless. Never again....

[steveo3002]

does sound like the garage are clueless

a decent place can plug it in then bring up dozens of live data readings that show whats going on with all manner of things , sounds like theyve just scanned for fault codes and called it a day

[CJ1]

steveo3002 said:

does sound like the garage are clueless

a decent place can plug it in then bring up dozens of live data readings that show whats going on with all manner of things , sounds like theyve just scanned for fault codes and called it a day

That’s what a suspect as well. They’ve had it for a total of 5 weeks now and I suspect it sits around doing bugger all....

[stevieturbo]

CJ1 said:

That’s what a suspect as well. They’ve had it for a total of 5 weeks now and I suspect it sits around doing bugger all....

I'm sure you would be within reason to ask them for a full written detail of all tests carried out and the results as you wish to consult a solicitor and the warranty company regarding their failures and the fact you now need to seek proper help at your own expense.

[Sardonicus]

stevieturbo said:

I'm sure you would be within reason to ask them for a full written detail of all tests carried out and the results as you wish to consult a solicitor and the warranty company regarding their failures and the fact you now need to seek proper help at your own expense.

Nothing to add here ^ sounds like one of those workshop that expects their diagnostic kit of choice to tell them whats wrong with DTC codes alone or at best the often crude on board component tests

[Arnold Cunningham]

Be slightly mindful that if it's misfiring, the Lambda may then report lean and richen it up a bit.

I've got this on an engine at the moment, it's definately too rich, but when I look at the Lambda reading it reports lean and old tuning software is trying to richen it up more.

[Krikkit]

Obviously a different engine, in part anyway, but a family member had an intermittent misfire issue with the 3 pot engine, turned out to be a fuel injector. Replaced and it was fixed for the rest of the time they owned it.

[vrooom]

I have same on my R50 mini (first gen n/a mini), i left it idling for first 5 min or i live with terrible shudder. i think they all do that.

[E-bmw]

They don't all do it by any stretch, plenty are fine as is my r53, purrs like a kitten.

Yours sounds like a temperature sensor to be that bad until it warms up, have you tried reading live engine data to see if all of the temperature sensors are working?