Cyl1 Misfire under load, even after replacement?

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Car model: BMW 325i Touring (2008)
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Cyl1 Misfire under load, even after replacement?

Post by Benaal » 13 Apr 2017, 10:52

Hi guys,

I've got yet another problem with my 325i.
It still appears to have a coolant leak somewhere, even after replacing the headgasket and the coolant reservoir. Takes about 2 weeks to empty but that's still very fast.

The main problem I am having now is, on the motorway or under load, reaching about 3k revs (or even less if going uphill) it starts to misfire, cough, and judder. The EML light comes on with the Cylinder 1 Misfire code. Sometimes I lose all power and sometimes I don't. I think it must turn cylinder 1 off somehow because after that, any accelleration feels like driving over a rumble strip. Cylinder 1 was replaced completely by a competent garage less than 100 miles ago. Had a fresh set of plugs at the same time. Don't know about the leads though - I think they're original.

Any ideas? my first thought is the fuel pump or some kind of sensor not getting enough fuel into the mix?

I'm also getting more than usual white smoke from the exhaust (all the time, not just on a cold morning) and an intermittent smell of burning oil.

Warranty will only pay £45/hr for labour, but I have it booked into a dealer for diagnosis. However, there's a BMW 'Specialist' around the corner from me, so do you think it's worth calling there first?


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Re: Cyl1 Misfire under load, even after replacement?

Post by Maxwell » 13 Apr 2017, 11:17

sound suspiciously like the head gasket get them to do a sniff test

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Re: Cyl1 Misfire under load, even after replacement?

Post by M60NJP » 13 Apr 2017, 11:26

As above. Unlikely to be fuel if it only affects one cylinder. You have an E90 so it may be worth dropping £40 on your local indie to see what a run code read throws up?

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