Hi Everyone, I hope someone out there can give me some (sensible) advice.
I have an 08 R56 Cooper S. The original engine blew, new engine has about 15,000 +/- miles on it.
The car has a new turbo, K&N cold air kit, 3" Turbo back exhaust, large aftermarket intercooler. I have a stage 3 tune on it from Cob. All else is stock.

When I put the new (used) motor in (13,xxx miles), it ran like a dream for about 8 weeks. At 3k rpm it takes off like a jet.
Then every so often, it would run like a pig on start up, even throw a check engine light. Id read the fault codes , clear them etc then it would be fine again.
First it did it only in very cold weather, if it was warm, no problem - Now it does this every time I start it, once its warmed up, it runs like a watch - perfect, and even more fun in sport mode.

Spoke with Cob, they said to check the plugs, probably incorrectly gapped.
bought new plugs, gapped them per recommendations - started it, same issue. Please let me know any suggestions ( not stupid comments please)
I'm frustrated and want to get thoughts from anyone kind enough to reply......

Thank you!

Matthew

 

what are the codes that you are pulling? That might help us out a bit. That definitely doesn't sound like plugs to me sorry Cobb

 

I had the exact same issue on cold start until the HPFP was replaced.

When the engine sits for more than a few hours (at work or overnight) it will struggle to maintain an rpm reading as if it would stall. Very frustrating since once I arrived at the dealership, under warranty, the issue was camouflaged because the engine was warm.

Good luck and I am sure some here will chime in with a technical explanation as to why.

 

HPFP as a educated guess. I have personally seen a dealer try to deny the issue.
Very common and under an extended warranty

 

Add one for fuel pump

 

o I completely agree with the fuel pump but he obviously is getting a code for something could be related or unrelated but it'd be nice to know before we guess lol

 

Gents, Firstly thank you so much for your responses!! I'll get the codes - I did have a fuel pressure code, but the pump was replaced with a new one, and it was ok for a while - could a pump go bad in 2,xxx miles? Ill be back at you all.

Thanks again!

Regards,

Matthew

 

I wouldn't exactly rule it out but I'd highly doubt it I've seen new parts fail out of the box and some weeks down the road never a hpfp but again wouldn't cross it off the list

 

There are some member's on their 3-4th HPFP.

 

ya that's y I wouldn't rule it out especially with a code for it