Supercharged BINI misfire
Turbo Mini Forums

Gents
Lisa's CooperS BINI supercharged gas developed a misfire which I've been trying to sort for a while now with not much success.
The BINI forums are bloody useless so thought I'd ask you bunch of knowledgeable chaps.
Basically it's a very intermittent misfire that's hard to replicate. Tends to do it mid way in the rev range but sometimes will stumble just off idle.
I've worked through the ignition system which hadn't really made much improvement. So far I've done plugs, leads (looked shitty), coilpack (a corroded terminal), plugs again with genuine plugs, still no better really. I thought it could have been oil contamination down the plug wells do I've had the cam cover off and changed all the seals.
I've also had my live data scanner on it, all the sensors seem to be showing believe able values, all are changing values as you may expect.
So I'm really running out of ideas, I don't really want to go throwing any more bits at it "just in case".
A guy I know mentioned that they can suffer from being down on compression but if I am honest I don't think it is, when it's not misfiring it goes like stink so I don't think there is anything massively mechanically wrong with it.

Any thoughts welcomed !

Just been reviewing the bini forums. Its hard to get some good advice.

Carbon build up has been mentioned a few times and what about a vacuum leak (granted more likely to be persistent)? Do these have an egr valve?

tom you say the coil terminal was corroded, did you just sort the terminal or change the coil ? if you didnt change the coil i would.

rob mentioned above vacume leak very possible, the EGR valve IMO unlikley but do remove the vacume pipe off it and runaround to see if your on the right track after the above ..............keep us posted buddy.

Im tired of working on my dads it ended up going home from mitp on a recovery truck with a seized coolant fan and coolant temps at 140 before it died the expansion tank cap swelled up like a baloon and it melted 2 plugs
It also uses about 1l oil a month but doesnt leak or blow smoke? Wtf

Anyway no great contribution however do these.have a maf? I think they doo
If its a hot wire type they can get coated in shit and this typicaly causes lean outs and stumbley misfires at part throttle
Skylines are terrible for this

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My sisters n/a 1.6 one strangely had a small piece of valve missing abd it developed a small misfire which i myself thought was electrical etc, took it to a mate thinking head gasket and turned out to be the valve was a goner, worth doing a compression test if you haven't done so already to rule it out.

carbon buildup is on the turbocharged direct injection engines as the inlet valves dont get washed with fuel. they also suffer from high, and low pressure fuel pump issues and breather issues all of which cause odd missfires. Tbo all of the supercharged ones i used to look after were generally pretty stout. i'd defo do a compression test, then it'd be fuel pressure.

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Denis O'Brien.

Tom have you had a leak down test done on the engine? that will tell you if you have any issues within the engine


Coil pack normally corrode on the one closest to the tank IIRC is cylinder 3 I'd only replace with a gen bmw part.

also check the MAP sensor and Lamba sensor

and is the intercooler full of Oil? does it use oil?

tbh without in front of me these only idea's i can say but if your close to

Gents
I've ordered a long stem for my comp tester so I'll get that done, I don't expect to find anything if I'm honest but worth ruling out.
Denis fuel pressure was one of my thoughts as well so I'll look at rigging up a gauge, usefully there is a test point on the end of the fuel rail.

Tom

just a small warning the fuel bump is a nightmare to remove.

try changing the filter in it aswell


remove the fuel pump relay start the car till it cuts out helps bring the pressure down but cover loads of plastic sheeting around fuel pump as its still under pressure when you release it.

Not a fun job done it a few times now.

Ok to finalise this.
Comp tested it all ok
Replaced fuel filter ( old was black and awful ) no better
Replaced front lambda no better

Still my gut feeling was ignition, so as a last throw of dice I ordered a s/h coilpack and leads off eBay
Hey presto misfire gone!
I haven't swapped bits round yet to isolate what was at fault, but damn annoying that new bits were faulty.

Seems such a common issue these days with faulty new parts

Fuel filter is always a good one to so it's jot long life as bmw claims and I did coil pack last night on my mates her misfire has gone now aswell you use a genuine one

No not a genuine one, but why should I have to? An aftermarket part has to be fit for purpose. There is nothing special about the OE coilpack, after all it is nothing more than lots of copper wire.

my clio had a misfire for ages, turned out it was incorrect spec plugs from manufacture, so as soon as I was coming on boost it would miss. its happening more and more with genuine new parts been in the wrong box etc, did a f30 bmw box said 300mm disc's inside the genuine bmw box were 325mm disc's. could have been something like this

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Hay mate, if you can't sort it it's worth speaking to the masters at 1320Mini http://www.1320.co.uk/ what they don't know about them isn't worth knowing :)

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I've always found bmw stuff to be better quality than aftermarket stuff in all honesty but that's my opinion on it