[ghost_m2c]

Hey all,
I think my injectors are about to shit the bed I am getting about 14 mpg average and it is only MHD stage 1 tuned. No visible fuel leaks on the car on the interior or exterior, can't smell any fuel, and the exhaust does not smell too rich. However, I have not pulled the spark plugs to see if the injectors were leaking yet. So I plan on getting plugs, coils, some fresh oil, and praying. Anyone have suggestions on possibly cleaning them? I dont know if I can take them out to clean but is there any fuel additives that may help? I really would like to resolve the issue without having to shell out a small fortune to get new ones. Especially since they are $2500 on FCP Euro (probably due to supply chain issues) not even including the stupid $100 tool and having to get them programmed at a dealership. I may consider getting them used but I think I would be best off getting them from FCP Euro just so I dont have to buy new ones ever again.

[E90lmao]

Originally Posted by ghost_m2c

Hey all,
I think my injectors are about to shit the bed I am getting about 14 mpg average and it is only MHD stage 1 tuned. No visible fuel leaks on the car on the interior or exterior, can't smell any fuel, and the exhaust does not smell too rich. However, I have not pulled the spark plugs to see if the injectors were leaking yet. So I plan on getting plugs, coils, some fresh oil, and praying. Anyone have suggestions on possibly cleaning them? I dont know if I can take them out to clean but is there any fuel additives that may help? I really would like to resolve the issue without having to shell out a small fortune to get new ones. Especially since they are $2500 on FCP Euro (probably due to supply chain issues) not even including the stupid $100 tool and having to get them programmed at a dealership. I may consider getting them used but I think I would be best off getting them from FCP Euro just so I dont have to buy new ones ever again.

From what I've heard and through my own research even the "bmw TIS" instructs not to clean the injectors with any solution as when you spray it with cleaner it can lodge the gunk into the top of the injector keeping it open and making the leak worse. I've seen there are a few specialty shops that offer pizo-injector cleaning but they usually only take index 12s. I went down this rabbit hole last year, a few leaky injectors similar symptoms to you but I also had rpm surging. I fixed the rpm surging by running liquimoly jectron injector cleaner every second tank at the pumps for about 2 cycles. It was only temporary and I had to repeat this every couple weeks to keep the injectors happy. I lucked out and found a set of used 10s and reinstalled them and coded them myself, and haven't had an issue since (fingers crossed).

[ghost_m2c]

Originally Posted by E90lmao

From what I've heard and through my own research even the "bmw TIS" instructs not to clean the injectors with any solution as when you spray it with cleaner it can lodge the gunk into the top of the injector keeping it open and making the leak worse. I've seen there are a few specialty shops that offer pizo-injector cleaning but they usually only take index 12s. I went down this rabbit hole last year, a few leaky injectors similar symptoms to you but I also had rpm surging. I fixed the rpm surging by running liquimoly jectron injector cleaner every second tank at the pumps for about 2 cycles. It was only temporary and I had to repeat this every couple weeks to keep the injectors happy. I lucked out and found a set of used 10s and reinstalled them and coded them myself, and haven't had an issue since (fingers crossed).

Ah, so jectron injector cleaner may help my problem? Was there any noticable difference aside from the rpm surging? Also, how were you able to code the injectors without the dealer? Im assuming you maybe have an autel tablet or a laptop to do that?

[Bimmer_Bro]

Originally Posted by ghost_m2c

Ah, so jectron injector cleaner may help my problem? Was there any noticable difference aside from the rpm surging? Also, how were you able to code the injectors without the dealer? Im assuming you maybe have an autel tablet or a laptop to do that?

Injector cleaner does diddly squat. Don't waste your money. First step is to see what index you have. There will be a number on them.
Next park your car over night. DO Not start it. Pull the plugs to see if they are wet. If they are, your injectors are leaking. This can cause much bigger and more expensive problems if ignored.
Replace injectors with index 12. There is a special tool and procedure to do this, yes they will also have to be coded. You may want a shop to do this if you are unfamiliar.

If all plugs look fine than it could be other problems like vacuum leak or boost solenoids that control the waste gates.

[TheMidnightNarwhal]

I feel you but honestly unfortunately if you find a leaky injector the only solution is to replace that leaky injector. A cleaner isn't going to make it not leak you know. The only way a cleaner can help is if the tip is carboned up I assume, it will not help in relation to any leakage from a seal or mechanical failure.

But there is hope to your wallet, you can just replace the problematic injector. Most people and actually the official BMW bulletin will tell you you need to replace at least 3 per bank but eh, I'm running 1 Index 12 with all Index 9s after replacing my cylinder 1 and no issues here. Other forum members run mismatched injectors as well with no reported issues.

And yeah to test for sure, let it sit overnight and make sure you do not start the car at all. Then pull all plugs and look and smell them. The leaky injector will make the plug smell a lot like fuel compared to the others. Also it's color, mine was all blacked up compared to the all other plugs which were of a ash/normal looking tip.

[E90lmao]

Originally Posted by ghost_m2c

Ah, so jectron injector cleaner may help my problem? Was there any noticable difference aside from the rpm surging? Also, how were you able to code the injectors without the dealer? Im assuming you maybe have an autel tablet or a laptop to do that?

Jectron helped with my jerky/surging rpm under load, it also cleared up a missfire on two injectors temporarily. It was a band aid fix while I searched for injectors. Luckily I have access to a snap on tablet so I was able to code them on that myself easily. Otherwise look up Diy injector coding, there is a program a few people use via a windows based laptop, there are a lot of walk through a and guides available online. In a perfect world I'd say get index 12s but those are hard to come by and they are extremely expensive. There are a few of us here who are not on index 12s and are getting by just understand that if you don't get 12s there's a risk it could do the exact same thing. For some of us it's simply not feasible to spend upwards of $3000 for some injectors and people need to understand that.

[E90lmao]

Additionally, it is possible that the leaky injector can cause engine problems down the road so try to resolve this sooner rather than later. Essentially you'd be leaking fuel and it will dilute your oil causing it to be less efficient. I'm not exactly sure if people have directly blown engines because of this but that is the risk of you leave it for a long time.

[ghost_m2c]

Originally Posted by E90lmao

Jectron helped with my jerky/surging rpm under load, it also cleared up a missfire on two injectors temporarily. It was a band aid fix while I searched for injectors. Luckily I have access to a snap on tablet so I was able to code them on that myself easily. Otherwise look up Diy injector coding, there is a program a few people use via a windows based laptop, there are a lot of walk through a and guides available online. In a perfect world I'd say get index 12s but those are hard to come by and they are extremely expensive. There are a few of us here who are not on index 12s and are getting by just understand that if you don't get 12s there's a risk it could do the exact same thing. For some of us it's simply not feasible to spend upwards of $3000 for some injectors and people need to understand that.

Seriously,
I mean I have money to fix most things on a car but $3k is a shitton of money for me. I walked into owning this car knowing damn well what I was getting into, still doesnt mean that I want to dump $3k when I can wait and get them cheaper. Eventually I will have to buy the injectors but id really like to wait it out until the prices go back down to ~$1500 even if it takes a few months. So it would be ideal to have a temporary fix for the time being.

[E90lmao]

Originally Posted by ghost_m2c

Seriously,
I mean I have money to fix most things on a car but $3k is a shitton of money for me. I walked into owning this car knowing damn well what I was getting into, still doesnt mean that I want to dump $3k when I can wait and get them cheaper. Eventually I will have to buy the injectors but id really like to wait it out until the prices go back down to ~$1500 even if it takes a few months. So it would be ideal to have a temporary fix for the time being.

Yeah for sure, in your situation I'd definitely try to find which injector(s) are leaking and pick up a used set of at least 10s or newer and get rid of the leaking ones as soon as you can, then get the 12s when you can afford them/the prices come down which ever comes first. I really didn't like running a leaky injector knowing I was dumping fuel into my oil. Sooner rather than later or it's going to get expensive real quick! I'm currently running 1 12 and 5 10s. I've seen a post where you must replace all in a bank with the same index so check online for that too.

[iqraceworks]

Originally Posted by TheMidnightNarwhal

I feel you but honestly unfortunately if you find a leaky injector the only solution is to replace that leaky injector. A cleaner isn't going to make it not leak you know. The only way a cleaner can help is if the tip is carboned up I assume, it will not help in relation to any leakage from a seal or mechanical failure.

But there is hope to your wallet, you can just replace the problematic injector. Most people and actually the official BMW bulletin will tell you you need to replace at least 3 per bank but eh, I'm running 1 Index 12 with all Index 9s after replacing my cylinder 1 and no issues here. Other forum members run mismatched injectors as well with no reported issues.

And yeah to test for sure, let it sit overnight and make sure you do not start the car at all. Then pull all plugs and look and smell them. The leaky injector will make the plug smell a lot like fuel compared to the others. Also it's color, mine was all blacked up compared to the all other plugs which were of a ash/normal looking tip.

This.

If 2,000psi of fuel pressure doesn't clean it out.....nothing you can run through it will. Replace it with a new one.

[studio54]

Originally Posted by Bimmer_Bro

Injector cleaner does diddly squat. Don't waste your money. First step is to see what index you have. There will be a number on them.
Next park your car over night. DO Not start it. Pull the plugs to see if they are wet. If they are, your injectors are leaking. This can cause much bigger and more expensive problems if ignored.
Replace injectors with index 12. There is a special tool and procedure to do this, yes they will also have to be coded. You may want a shop to do this if you are unfamiliar.

If all plugs look fine than it could be other problems like vacuum leak or boost solenoids that control the waste gates.

I wanted also to check my injector to see if plugs tips are wet, but is it necessary to let it overnight ? I assume that it leaks with the residual fuel pressure, and if it leaks by a good amount until pressure too low, won't it be already dry next day, especially how hot are our engines ?

Is it ok to check them like 1 or 2 hours after stopping ?

BTW, OP maybe your injectors are OK since you haven't physically checked them yet, do you have some lambda/stft/ltft logs ? Does one of your lambda bank AFR is lazy to return to 234 on let off for example?

[Bimmer_Bro]

Originally Posted by studio54

I wanted also to check my injector to see if plugs tips are wet, but is it necessary to let it overnight ? I assume that it leaks with the residual fuel pressure, and if it leaks by a good amount until pressure too low, won't it be already dry next day, especially how hot are our engines ?

Is it ok to check them like 1 or 2 hours after stopping ?

BTW, OP maybe your injectors are OK since you haven't physically checked them yet, do you have some lambda/stft/ltft logs ? Does one of your lambda bank AFR is lazy to return to 234 on let off for example?

I'm guessing 1 or 2 hours may not be enough since they would stay warm for quite a while in there. It would depends how bad they are leaking. Most wait overnight before checking.

[TheMidnightNarwhal]

Originally Posted by studio54

I wanted also to check my injector to see if plugs tips are wet, but is it necessary to let it overnight ? I assume that it leaks with the residual fuel pressure, and if it leaks by a good amount until pressure too low, won't it be already dry next day, especially how hot are our engines ?

Is it ok to check them like 1 or 2 hours after stopping ?

BTW, OP maybe your injectors are OK since you haven't physically checked them yet, do you have some lambda/stft/ltft logs ? Does one of your lambda bank AFR is lazy to return to 234 on let off for example?

I think they leak when cold. My injector leaking was only prominent to the point of finally having a missfire code on startup when it was the coldest winter weather here. Although I think it was just starting to leak overall because using my car daily I barely noticed leakage behavior and to this date my spark plugs are working fine. It was over like 2-3 days of not using the car that I could get a code and notice bad idle. May just be a coincidence, didn't waste to much time and replaced it.

[335i54n]

leave the car cold overnight, before cranking unplug all the injectors. crank for 15sec, pull plugs and smell.

there couple places that will test and clean injector but they only do them for index 12

only fuel additives that have pea are worthwhile, iirc like gumout or redline s1=best/most pea concentration

[Saif2018]

Injector cleaning doesn't really work, especially if your injector is leaking. Tried it before I replaced my index 1 injectors, they were still leaking.

Only real solution to N54 leaking injectors is to bite the bullet and replace them

[iqraceworks]

Originally Posted by 335i54n

leave the car cold overnight, before cranking unplug all the injectors. crank for 15sec, pull plugs and smell.

there couple places that will test and clean injector but they only do them for index 12

only fuel additives that have pea are worthwhile, iirc like gumout or redline s1=best/most pea concentration

You don't need to mess with all of that. Run the car, shut it off....let it set all night, pull the plugs in the morning and look for wet ones. Pulling the injector plugs and cranking the motor over does nothing...it's a waste of time. The pressure in the fuel rail will push the fuel out of the leaky injectors and run down onto the spark plug tips. Why wait all night and then crank the motor over in the morning?? Bad idea.....

[iqraceworks]

Originally Posted by Saif2018

Injector cleaning doesn't really work, especially if your injector is leaking. Tried it before I replaced my index 1 injectors, they were still leaking.

Only real solution to N54 leaking injectors is to bite the bullet and replace them

Agreed. If 2000psi fuel flowing through them doesn't clean the crap out of them....a little additive isn't going to do a thing. Welcome to the N54....if you can't afford to maintain it, sell the car and get a Honda.

[studio54]

Originally Posted by TheMidnightNarwhal

I think they leak when cold. My injector leaking was only prominent to the point of finally having a missfire code on startup when it was the coldest winter weather here. Although I think it was just starting to leak overall because using my car daily I barely noticed leakage behavior and to this date my spark plugs are working fine. It was over like 2-3 days of not using the car that I could get a code and notice bad idle. May just be a coincidence, didn't waste to much time and replaced it.

Originally Posted by Bimmer_Bro

I'm guessing 1 or 2 hours may not be enough since they would stay warm for quite a while in there. It would depends how bad they are leaking. Most wait overnight before checking.

Okok thanks, prior smelling/checking plugs, without opening engine bay, and since you have to let it rest over night, I would imagine it could be also possible to check for a leak by just reading rail pressure psi in MHD logging the next morning?

Probably just shut off engine after a standard commute, remove LPFP fuse (to avoid unlock key wake up priming), let the car sit overnight, and next day, log rail pressure without starting the engine. It should be stayed in the ~70psi since the fuel check valve supposed to hold that.

I never logged an engine shut off so I don't know actually how long rail pressure (HPFP) holds pressure, but I think the check valve before LPFP should hold in the 70 psi if no leaks.

If an injector is leaking I think it will lose a good amount of pressure over night, and then you can check plugs?