[Mircea]

Originally Posted by mahoone

Having the old injectors in the bank 1 (or 2) won't affect the new ones in another bank. So you can have x3 index 11 injectors in bank 1 and old injectors (index 8?) in bank 2.

New injector would be only affected if you replaced 1 faulty injector in one bank and leave the old ones still in i.e.: 5 old injectors and 1 new. Exception to that would be if you had 6 index 11 injectors (latest ones) and one of them failed - then you only replace 1 faulty injector.

Great, thank you for this.

At the same indy I've mentioned earlier, I've been quoted a bit over £1000 for replacing 3 injectors with index 12s, and a bit over £1900 to replace all 6. Pretty expensive based on what other users on these forums paid so I will keep them as a last resort.

What are your thoughts about https://www.ebay.co.uk/itm/BMW-FUEL-...E/323584021962 ? They're the only brand new injectors I've found on ebay for the n53, and they're supplied by Cooper BMW in Tunbridge Wells, and come with a 2 year warranty. Fair price?

Come March, I will replace the first 3 and then come summer, I will do the rest.
Hopefully until March, the new spark plugs I've just fitted Monday won't become too worn out by that leaky injector. I don't plan on putting more than 1000 miles on it until then anyway but we'll see.

[Tr1ppy]

Just bear in mind that the injectors on N53 go up to index 11. Only N54 injectors go up to index 12

[Mircea]

Originally Posted by Tr1ppy

Just bear in mind that the injectors on N53 go up to index 11. Only N54 injectors go up to index 12

Ah cool, I didn't know this and I asked the indy if the injectors are index 10/11/12 and they just said they are of the later index (these are the latest version from BMW).

I have asked now if they're ok with me sourcing the injectors, I'd get them from the ebay link I posted earlier as those seem like a good deal with 2 years BMW warranty.
If not, I'll have to look into another garage that could fit and code 3 of these in bank 2.

How much labour time do you think this would normally take?

[Tr1ppy]

I did mine like that, starting with bank 1 and then couple months later, bank 2.

Each time it took my indy less than 3 hours and thats including changing coils and plugs for that bank and fitting and coding the injectors.

[Mircea]

Well this indy took 2.5h to change my valve cover gasket, 6 spark plugs and 6 coil packs. Pretty fast if you ask me, so I'm wondering how 6 injectors + labour added up to £1900 when the injectors themselves are at their most expensive £1400 total.

[Sir_Dave]

Originally Posted by Mircea

Well this indy took 2.5h to change my valve cover gasket, 6 spark plugs and 6 coil packs. Pretty fast if you ask me, so I'm wondering how 6 injectors + labour added up to £1900 when the injectors themselves are at their most expensive £1400 total.

Thats probably about right time wise to include doing the rocket cover gasket. It takes about 30 mins to change 6 spark plugs/coilpacks.

Injectors wise, as per the coils/sparks, its VERY easy to DIY, as per this thread: https://www.e90post.com/forums/showthread.php?t=651538

£2k for supply & fit is an utter ripoff also, the fact they are just saying "change all of them" is annoying, if you have 3 knackered ones across both banks, its perfectly fine to run 3 matched Index 11's and 3 others on the other bank, as long as they are properly coded. FWIW, changing an injector takes about 15-20 minutes.

I've budgeted circa £150 each for new injectors, or up to £100 each for Index 11's 2nd hand (they seem to last better than previous indexes), bear in mind that you'll need this tool in order to get the new teflon seals on the end of the injector if you buy 2nd hand: https://www.ebay.co.uk/itm/Bosch-Mar...l/153201885798

If you are fairly local to Weybridge, im happy to code them for you if needs be

[Mircea]

Originally Posted by Sir_Dave

Thats probably about right time wise to include doing the rocket cover gasket. It takes about 30 mins to change 6 spark plugs/coilpacks.

Injectors wise, as per the coils/sparks, its VERY easy to DIY, as per this thread: https://www.e90post.com/forums/showthread.php?t=651538

£2k for supply & fit is an utter ripoff also, the fact they are just saying "change all of them" is annoying, if you have 3 knackered ones across both banks, its perfectly fine to run 3 matched Index 11's and 3 others on the other bank, as long as they are properly coded.

I've budgeted circa £150 each for new injectors, or up to £100 each for Index 11's 2nd hand (they seem to last better than previous indexes), bear in mind that you'll need this tool in order to get the new teflon seals on the end of the injector if you buy 2nd hand: https://www.ebay.co.uk/itm/Bosch-Mar...l/153201885798

I'll get these, which aren't second hand as far as I could tell from the classified: https://www.ebay.co.uk/itm/BMW-FUEL-...E/323584021962
I don't have any tools and I'm not too handy with mechanical/hardware stuff at all so I'd rather let working with the combustion components of an already rather fragile engine to the hands of someone who knows what they're doing
If you're that confident, Surrey isn't too far away from me so if you're looking to make a fair quid replacing these over a Saturday sometime soon let me know

[Sir_Dave]

Originally Posted by Mircea

I'll get these, which aren't second hand as far as I could tell from the classified: https://www.ebay.co.uk/itm/BMW-FUEL-...E/323584021962
I don't have any tools and I'm not too handy with mechanical/hardware stuff at all so I'd rather let working with the combustion components of an already rather fragile engine to the hands of someone who knows what they're doing
If you're that confident, Surrey isn't too far away from me so if you're looking to make a fair quid replacing these over a Saturday sometime soon let me know

Yeah, those are brand new from BMW, so simply a case of removing the old injectors, then putting those in instead - no messing about with replacing seals. Dont forget to buy new "decouplers" as well though, they help hold the injector into the cylinder head: https://www.ebay.co.uk/itm/BMW-Genui...nt-13537564751

As it happens, I'll be replacing all mine at some point fairly soon once ive got my new cylinder head fitted (i've done one already as per this thread: https://www.e90post.com/forums/showthread.php?t=1573305), so yeah, more than happy to give you a hand if needs be; am fairly busy the next few weekends, but if its something you're looking to do in March that should be fine

[Mircea]

Originally Posted by Sir_Dave

Yeah, those are brand new from BMW, so simply a case of removing the old injectors, then putting those in instead - no messing about with replacing seals. Dont forget to buy new "decouplers" as well though, they help hold the injector into the cylinder head: https://www.ebay.co.uk/itm/BMW-Genui...nt-13537564751

As it happens, I'll be replacing all mine at some point fairly soon once ive got my new cylinder head fitted (i've done one already as per this thread: https://www.e90post.com/forums/showthread.php?t=1573305), so yeah, more than happy to give you a hand if needs be; am fairly busy the next few weekends, but if its something you're looking to do in March that should be fine

April most likely as in March I have quite some things happening.
Until then I will quote around local garages and independent shops to see what labour prices they come up with for replacing 3 of them.
Ideally I'd like a receipt for the work for record-keeping purposes because I'm obsessed like that but if they're all being ridiculous I will let you know in due time and we can plan this further. Guessing you'll remain active on this forum? If not maybe PM me an email I can get to you at

[Sir_Dave]

Originally Posted by Mircea

April most likely as in March I have quite some things happening.
Until then I will quote around local garages and independent shops to see what labour prices they come up with for replacing 3 of them.
Ideally I'd like a receipt for the work for record-keeping purposes because I'm obsessed like that but if they're all being ridiculous I will let you know in due time and we can plan this further. Guessing you'll remain active on this forum? If not maybe PM me an email I can get to you at

Yeah, ill be on here for a while yet ... have had a BMW daily in my life pretty consitently for the past 15 years. Although the N53 has thrown up more issues than most of the others put together

Will drop you my contact details anyways, maybe try BMSSurrey & TWG Camberley as well, have used both of them for things i cant be bothered to do. If not, April is fine by me

[OliSharp]

Sir-Dave, did you have to use an injector puller or did yours come out using your fingers? I had a go at mine last weekend and couldn't get it to budge.

[Mircea]

I am interested in this too, as I think I will do them myself, saves hassle and cash.

Also, any ideas on how to spot the leaky injector or at least what bank it is/they're on without taking the spark plugs out?
Can I verify some parameters in INPA to check for abnormalities?

[OliSharp]

Looking at the spark plugs is probs the best way. My code reader said misfire cylinder 2 when the spark plug in cylinder 3 was the one covered in petrol from the leaky injector. Glad I checked, INPA may be different though.

You'll need an 8 mm socket, 5mm allen key, a spark plug socket, and a small flat bladed screwdriver to undo plastic clips.

I watched a youtube video by Justin Buice before I go the spanners out, which I found very informative.

Putting the plastic bits back on is a bit of a faff so allow enough time.

If anyone has tips for removing stuck injectors please let me know! My injector wobbles slightly from side to side but doesn't want to come out. I'm not sure the slide hammer on a tool such as the Laser would put enough force to get it unstuck.

[mahoone]

Originally Posted by OliSharp

Looking at the spark plugs is probs the best way. My code reader said misfire cylinder 2 when the spark plug in cylinder 3 was the one covered in petrol from the leaky injector. Glad I checked, INPA may be different though.

This is exactly what happened to me. According to INPA I had misfire on cylinder 2 but the faulty injector was in fact on No 3.

OP, have a look at bimmerprofs.com. I'm sure there is a guidance on there on how to diagnose a leaky injector.

[Mircea]

Originally Posted by mahoone

This is exactly what happened to me. According to INPA I had misfire on cylinder 2 but the faulty injector was in fact on No 3.

OP, have a look at bimmerprofs.com. I'm sure there is a guidance on there on how to diagnose a leaky injector.

Yeah, kind of same to me.
My cheap OBD scanner was reading misfire on cyl2 and when the mechanics did the servicing on it, they told me that it was cyl4.
But this was before they'd taken out the spark plugs to replace them so I don't know exactly if they were just baffling.

I think I'll just change all 6 of them at once anyway as that possibility of an engine fail due to oil contamination with fuel really really scares me.
The car has been having this issue since I got it last year in June (put about 4k miles on it and 4L of oil) and I have no idea how much it's been going on before that... so yeah

[Fritzer]

Valve Cover Gasket. While you're in there clean out the VANOS solenoids, and of course the oil in the coil pack chambers. There may be some oil on your plugs too. To be completely honest if you can budget it in I would replace all coils/plugs as well, just to be 100% sure. I would imagine this would fix your issue.

[Mircea]

Originally Posted by Fritzer

Valve Cover Gasket. While you're in there clean out the VANOS solenoids, and of course the oil in the coil pack chambers. There may be some oil on your plugs too. To be completely honest if you can budget it in I would replace all coils/plugs as well, just to be 100% sure. I would imagine this would fix your issue.

If you've tracked the replies since the original post, I have replaced the valve cover gasket, coil packs and spark plugs and the misfires definitely still happen with exactly the same symptoms.

I am now going to replace injectors with brand new index 11 ones.

[Fritzer]

Originally Posted by Mircea

If you've tracked the replies since the original post, I have replaced the valve cover gasket, coil packs and spark plugs and the misfires definitely still happen with exactly the same symptoms.

I am now going to replace injectors with brand new index 11 ones.

My bad! Just read the original post before I replied! Could be injectors, definitely something with the head though, or fuel system. Can't think of anything else that it could be. You are getting the same exact codes before you replaced all the other items? I wonder if it's something to do with the valves, I know that sometimes the cams can wear down and improperly depress the valves from opening/closing. Not sure if that would cause misfires or not.

Hopefully it's not something inside the block, I doubt it would be. Worse case scenario find a used head, I believe for N51/N52 they cost around $750-$1,000 USD. Don't quote me on that though, I feel like I got that figure from a salvager or something.

[Mircea]

Originally Posted by Fritzer

My bad! Just read the original post before I replied! Could be injectors, definitely something with the head though, or fuel system. Can't think of anything else that it could be. You are getting the same exact codes before you replaced all the other items? I wonder if it's something to do with the valves, I know that sometimes the cams can wear down and improperly depress the valves from opening/closing. Not sure if that would cause misfires or not.

Hopefully it's not something inside the block, I doubt it would be. Worse case scenario find a used head, I believe for N51/N52 they cost around $750-$1,000 USD. Don't quote me on that though, I feel like I got that figure from a salvager or something.

It's an N53 but the price sounds about right.
I'll replace the injectors as they are most likely the cause given the symptoms, especially the strong petrol smell when starting cold when the idle is at its roughest.

[Fritzer]

Originally Posted by Mircea

It's an N53 but the price sounds about right.

Yeah I was just referencing our prices because we don't have the smaller N53 in the states. The engines are similar enough that the prices are probably in the same range, roughly.

[Mircea]

Update on this.
I am still trying to make sure of what the issue is exactly before I dive into buying parts.

I have contacted the team at bimmerprofs.com and sent them screenshots from various menus in INPA to get a diagnosis made.
They suggested that the fix would be just the NOx converter, so they advised getting their NOXEM and that that would fix it.

After I mentioned that I think the problem might be injectors, and that the NOX converter fault might be a result of this, they told me the screens don't confirm injector faults...

https://www7.zippyshare.com/v/pLBHLCzi/file.html
(too large for attachment on post)

All the screenshots are in that zip. As you can see from the error history folder, between NOx related errors, it's always been mentioning cylinders 2 and 4 (seem to be happening rarely and around the time I got the CELs too). This makes me think that the injectors on cylinders 2 and 4 are knackered.
My bimmerprofs diagnostic is also in one of those folders, if you want to have a look.

What do you guys think? Should I go with the approach of getting the NOx converter replaced first and see if that fixes it?

What I'd go for ideally, would be to swap injectors 1 and 4, so what I think are both bad injectors, get to be on bank 1 and replace this bank with index 11s, see if that fixes it and then if not, the NOXEM approach.

The way bimmerprofs suggested, by just replacing the converter with NOXEM would save me cash in the long run against 3x injectors, but might prove to fix nothing at all...

What would you do?

[Phil325i]

I doubt NOx sensor would cause a misfire. I still think you're right - it's injector(s). See this thread:

https://www.e90post.com/forums/showt...5#post23587995

If you can afford it, I'd replace all six injectors, not just one bank.