[fozzydj]

Hi all,

I wondered if I could reach out for some advice.

Im the proud owner of a 2007 N54 driven 335i coupe and recently have been experiencing a miss fire/juddering from a cold start for the first 2 minutes of driving. It then runs smooth and fine, even after a stop at the shop etc.

Ive owned the car for 3 years, its done 146k miles and some recents bits are below:

Index 12’s on recall a year ago
New Mitsubishi turbos 3 months ago
New timing chain kit 3 months ago (stretched, done same time as turbos)
NGK 1 step colder plugs (3 months ago)

I believe its MHD stage 2 (done prior to my ownership, no issues throughout its time with me - burbles in sports mode) with a XHP gearbox map.

I cant vouch for the coils - they look OEM and no history to say they have ever been changed - this was going to be my first port of call, Im going to stick a set of new Dinan coils on.

Couple of pics, gotta custom Nardo paint job

[suspect]

What you’re describing sounds like a bad injector. Index 12 also go bad. A way to check would be to let the car sit overnight and then pull the spark plugs. The cylinder with bad injector will have a spark plug wet with fuel or will be covered in soot because of bad spray pattern. To rule out other fuelling issues you could check the rail pressure. Any obd scanner app would show you but it’s best to get MHD. About 700 psi at idle and 2000-2800 psi at WOT. LPFP should be around 70psi (this might not be accessible without MHD or INPA). Heard good things about dinan coils.

I assume you’re in the uk because of the number plate? How did you get index 12s on recall? As far as I’m aware the recall wasn’t here.

[bigsurge]

does your car go through the cold start ritual where the rpms are elevated? if not try enabling that

[whyzee125]

Likely a leaking injector. Take a look at all plugs and see if one or more are wet.

[fozzydj]

Thanks for the advice chaps.

Interestingly this morning when I started the car from cold I let it idle until the cold start process had finished and the rev's settled - I got the judder a couple of slight times and then it was gone - so letting it cold start correctly seemed to improve it.

I will pull the plugs this weekend and have a look at the condition of them.

Thanks again.

[fozzydj]

Originally Posted by suspect

What you’re describing sounds like a bad injector. Index 12 also go bad. A way to check would be to let the car sit overnight and then pull the spark plugs. The cylinder with bad injector will have a spark plug wet with fuel or will be covered in soot because of bad spray pattern. To rule out other fuelling issues you could check the rail pressure. Any obd scanner app would show you but it’s best to get MHD. About 700 psi at idle and 2000-2800 psi at WOT. LPFP should be around 70psi (this might not be accessible without MHD or INPA). Heard good things about dinan coils.

I assume you’re in the uk because of the number plate? How did you get index 12s on recall? As far as I’m aware the recall wasn’t here.

When I purchased the car (private from an individual) he handed me a recall letter for it. I literally booked it in - BMW had it for a few days. When I collected they advised the injectors had all been replaced with index 12s, but refused to provide me any paper proof of this as the work was "free" so they couldn't give me a receipt for the injectors or anything.

I may have the recall letter at home still, I will pop a picture of it up if I can find it.

I have owned a same year 335i prior to this one and never had a recall for the injectors - I had to purchase them myself (I got lucky and found a dealer code so ordered them at around £75 each a few years ago!)

[suspect]

Originally Posted by fozzydj

When I purchased the car (private from an individual) he handed me a recall letter for it. I literally booked it in - BMW had it for a few days. When I collected they advised the injectors had all been replaced with index 12s, but refused to provide me any paper proof of this as the work was "free" so they couldn't give me a receipt for the injectors or anything.

I may have the recall letter at home still, I will pop a picture of it up if I can find it.

I have owned a same year 335i prior to this one and never had a recall for the injectors - I had to purchase them myself (I got lucky and found a dealer code so ordered them at around £75 each a few years ago!)

Would be good if you happen to dig out some more info I’d like to try my luck on getting bmw to fit new injectors considering they’re now about £400 each.