Help with a misfire?

zmaster007 · Post by **zmaster007** » Fri Jan 13, 2017 1:54 pm

Hi guys,

Yesterday I had some misfires with the M - only when going up past 7000rpm. The car puts on the engine light and runs lumpy. Restart it - ran fine. Ran the codes, said cylinders 1,2,6 misfire. Cleared the codes and tried it again, this time came up with cylinder 4. Cleared again - cylinder 4 again.

Today I had planned to investigate further, but now I can't provoke it in to misfiring! Only thing I changed recently was a quarter tank of regular fuel which was then topped up with super.

INPA says the O2 sensor voltages are fine.

Any ideas?

dannytheduck1985 · Post by **dannytheduck1985** » Sat Jan 21, 2017 11:41 pm

Had this problem mate.
Won't rev past 7k and occasionally misfires whilst idling. You Scan the car and throws up misfire on various cylinders. Reset, it's fine but comes back occasionally.

Sounds daft but First test your battery. Low power will cause your ecu to become confused. If that's ok then test the alternator output and data line module on the back of the alternator. The data module was faulty on mine.

Pm me if you need any more info

zmaster007 · Post by **zmaster007** » Sun Jan 22, 2017 3:29 pm

Thanks for the advice - is checking the alternator/data module as simple as sticking a multimeter on it like the battery?

D4dawg · Post by **D4dawg** » Wed Jan 25, 2017 12:14 am

Doesn't sound fun
Remember these toys are 9 and 10 now
As mine spat out its dummy over its alternator
Tested at bmw and said it was battery
Bought new one, turned out it was alternator !
So have a new battery and alternator now

Battery tested fine and alternator due back v soon after overhaul and new regulator as £750! From bmw
Could test on battery and leads going into it should read 13.9 v buddy

Motty · Post by **Motty** » Wed Jan 25, 2017 12:59 am

D4dawg wrote:Doesn't sound fun
Remember these toys are 9 and 10 now
As mine spat out its dummy over its alternator
Tested at bmw and said it was battery
Bought new one, turned out it was alternator !
So have a new battery and alternator now

Battery tested fine and alternator due back v soon after overhaul and new regulator as £750! From bmw
Could test on battery and leads going into it should read 13.9 v buddy

That's a bugger. How much did the alternator cost you?

D4dawg · Post by **D4dawg** » Wed Jan 25, 2017 10:34 am

Bmw sell them for lovely £750 buddy
Luckily my car has a warranty
But I'm. Paying to have mine refurbished then I'll sell it on here

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