[Phil325i]

Originally Posted by Series3

Hi everyone,

I was bold enough to get a 2008 e90 325i with the N53B30A engine and 135k kms. Sure enough, it's having a bit of a rough idle on a cold start and the EML came on for a cylinder 1 misfire. After reading a bit, I'm assuming it's probably a bad injector... I'm gonna smell the spark plugs tomorrow.

Question - are the N54 index 12's any better than the N53 index 11's? Any idea about reliability/longevity compared? If the N54 index 12's are noticeably better, I guess I would get 3 of these for a bank. Otherwise, maybe I just replace the ones that are bad with index 11's. Joy of joys... the car is in excellent condition otherwise and I'd be sad to throw it away.

Cheers,
Bruno

Hi Bruno. I've had N54 (Index 12) injectors fitted to my N53 engine for over 2 years and 15,000 miles without issue. So some indication of longevity? Maybe. Are they better than N53s? I don't know. However they are index 12 (N53s are still at index 11) and the changes to the upgrade for index 12 were significant (internal filter fitted and use of optimised thermal compensating oil) so they are the best injectors currently available in my opinion.

I went for N54s because at the time N53 injectors were out of stock everywhere (post-Covid). Opinions vary on replacing injectors on one bank only. I think if you're fitting like-for-like (in other words N53 injectors) then doing one bank only might be OK. However I've read that changing to N54s in one bank only (with N53s in the other) is a no-no.

Hope that helps...

[Series3]

Originally Posted by Phil325i

Hi Bruno. I've had N54 (Index 12) injectors fitted to my N53 engine for over 2 years and 15,000 miles without issue. So some indication of longevity? Maybe. Are they better than N53s? I don't know. However they are index 12 (N53s are still at index 11) and the changes to the upgrade for index 12 were significant (internal filter fitted and use of optimised thermal compensating oil) so they are the best injectors currently available in my opinion.

I went for N54s because at the time N53 injectors were out of stock everywhere (post-Covid). Opinions vary on replacing injectors on one bank only. I think if you're fitting like-for-like (in other words N53 injectors) then doing one bank only might be OK. However I've read that changing to N54s in one bank only (with N53s in the other) is a no-no.

Hope that helps...

Thanks so much for the reply. I ended up returning the car, after confirming that indeed the spark plugs reaked of gasoline and were the worst looking spark plugs I had ever seen in my life.

The injectors were index 9, all of them, and I didn't really feel like going through all that hassle, not even knowing if there had been maybe some more internal damage due to oil contamination. So I returned the car and now bought another E90 but this time with the N52 engine