2.5si running terribly?

tractorbob

New member
Hi
Just managed to get on here and hope for a bit of help.

September last year bought a Z4 2.5si auto roadster 2007 with 34k miles and been over the moon.

Noticed over the last month or so that when sitting in drive at a junction etc the engine seemed to miss slightly. This has got progressively worse to the point today where it is almost undrivable. Starts nice from cold but doesn't take long until it starts running really badly.

Been lurking on here until I finally got the account activated today and have looked at all similar threads so have checked coil packs and although I initially thought it was the issue, it runs so badly that it really is difficult to tell if there is a problem here? Disconnected the maf sensor and no difference so guess it is fine? Had the vanos solenoids out and cleaned, again no difference.

Obvious questions, any ideas what to look for next? Should be able to read fault codes tomorrow. As it was quite low mileage when we got it the service history is a bit scetchy. Guess it can't be as simple as plugs as it runs quite nicely from cold and when pushed hard does clear and pull quite well. Do the faults need to be cleared to make a difference?

Any help would be greatly appreciated as its a daily drive for the misses and although I have a good specialist garage that I use, both he and us are stuck for time so could do with getting even a relatively quick fix so it can be booked into garage at a time that fits better.

Cheers
 
I'm no expert but have you inspected the DISA valve? If that is failing it could lead to rough running- do a search on here as there's loads of info for how to check/ replace them. Quite a common fault I believe.
Hth
 
Thanks for that. It's something else to consider and check.

Will the faults need to cleared to see any difference to the things I have done / checked? Engine light been on for a couple of days now?

Cheers
 
I would still be guessing at coils ,where are you based,if you are close to south yorkshire .
I will have a spare set in the next couple of days, you could use to test.
At least this will defo rule them out.
 
Thanks for your replies.

Managed to get the fault reader plugged in just there and hopefully good news and hopefully just as mentioned. Misfire on 4 and 6. I couldn't really tell any difference when disconnecting the coils at the weekend , but hopefully worth getting another coil to add to the one I got at the weekend. Any other advise welcome and I will keep updating.

Cheers
 
If no difference when swapping coils then it could be plugs. If you've not had an Insp2 carried out then they won't have been changed.
 
Can't remember the exact mileages but it was close to needing a service when we bought it from a 'specialist' and was promised a service and mot when we did the deal. Mot was done but I would think nothing more than reset of the trip computer and a wipe over with an oily rag.

Update - all is good bought another coil pack today and fitted tonight and purring like a kitten again. I have plugs coming anyway so just for piece of mind will get them fitted. I will get it into the local BMW spot ASAP to get back on track with what is needed.

Thanks for all the help and replies. These forums are so useful.
 
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