[LKN624]

So I have been reading up on these Fuel Injector issues which seems to be super common. I am having the symptoms of a leaky injector (ie. started to smell fuel when I started up the car from a cold start, then day later started from cold start again and saw that the Check Engine Light come on and saw the code for a Cyl 6 Misfire. (I saw this when I bought the car last month but thought it was just simple old plugs and coils, which I replaced right away). I turned off the engine and back on and the light of course turned off and check for codes...nothing. Car ran smooth as butter and blasted down the Autobahn with ease. Looking into this it looks like I need to replace all 6 with Index 11's.

Questions are: I am planning on leaving the car sit until I can order the new Index 11 injectors, install and program them to the car, but will the car be fine with the car just sitting there? It won't be for a few weeks until I can get to it so I am just worried if the injectors will leak fuel into the cylinders if left just sitting there. Should I remove the injector and cap everything off? This morning I just disconnected the battery just to be safe.

Also, when I do get the new injectors in and programmed, I am sure I will have to replace the oil (to rid of possible fuel contamination) and spark plugs. Would fogging oil be recommended to spray into the affected cylinder before I start the car up for the first time? I would assume the fuel has washed any oil film away from the cylinder walls...

Any insight is appreciated.

Many thanks!

[Phil325i]

I think you would be wise to remove the injectors. The leaking fuel can damage the cylinder coating. Take the injectors out and block up the holes to prevent dirt getting in while you lay the car up. I wouldn't use any sprays - just fit the new injectors and re-programme and you'll be fine.

[LKN624]

Sounds good, I just hope I didn't do any permanent damage...

[LKN624]

UPDATE: Just took a look at the indexes of my Fuel Injectors...looks like all of them are Index 11.

THEN...

Actually just saw this in a Service Bulletin from BMW.

IMPORTANT: Injectors with index 11 and higher have a different calibration and construction than
injectors with index 10 and lower.
Due to this difference, the injectors with index 11 and higher and injectors with index 10 and lower cannot
be mixed on the same engine bank (i.e., cylinders 1-3 or 4-6).
Once a bank of injectors is at index 11 or higher, the “bank set replacement” requirement no longer
applies. For index 11 injector failures, only replace the failed injector.

Which means...looks like I am safe from having to replace all 6 injectors? Or is my reading comprehension off?

[Phil325i]

Yes I think you're right, though you may still need to change all in the same bank (cyl 1-3 or 4-6). Surprised index 11 injectors are failing though. First person I've read whose had one go bad...

[LKN624]

Yeah I will start with the new Fuel Injector, Coupler and Spark Plug for safe measure. I did take out the Cyl 6 (Problem) Spark Plug to smell it and it definitely smells like fuel. It wasn't wet at all but it did smell of fuel. I took out Cyl 1 Spark Plug to compare the smell and condition. They look about the same, but Cyl 1 did not smell of anything. Should be getting the new Injector hopefully end of the week, install, code and run and will report back.

And yes to confirm all of my Injectors are Index 11's. I also heard people having issues with these as well still.

Link to where I got the above information.

https://static.nhtsa.gov/odi/tsbs/20...29104-4598.pdf

[Dormermike]

ISTA has an injector test function, never used it myself, but may be worth doing here to identify faulty ones..

[LKN624]

Originally Posted by Dormermike

ISTA has an injector test function, never used it myself, but may be worth doing here to identify faulty ones..

Yeah I will do that once my cable comes in just to see but definitely is Cyl 6 being the problem child. I'll take a look at the others.

[LKN624]

So update on the topic. Replaced the Fuel Injector with Decoupling Element and coded it to the car. No more fuel smell or misfire that I can detect. Changed the oil and doing an oil analysis to see if there's anything to worry. Which is the next hurdle, hopefully the extra fuel didn't dilute the hell out of the oil!

[LKN624]

Started it up this morning to drive and there it goes again...Engine Cyl 6. Misfire. Any ideas? CEL came on as well.

[Dormermike]

Not sure if you've tried already but try moving coilpack and plug from a cylinder on a different bank and see if that misfire moves...

Otherwise, if its definitely an injector fault on a new injector lookup mosfet and loom faults with the DME. Rare though.

[LKN624]

Originally Posted by Dormermike

Not sure if you've tried already but try moving coilpack and plug from a cylinder on a different bank and see if that misfire moves...

Otherwise, if its definitely an injector fault on a new injector lookup mosfet and loom faults with the DME. Rare though.

Thanks for the reply! Yeah already swapped coil packs and plugs, put in another new coil and plug and the misfire is still there. Previously I was able to shut the car off, clear the code and it would be fine...no misfire. Now if I start it, (it starts up immediately by the way 1-2 cranks), it will idle then turn into a rough idle and then the Engine light (Full) comes on. Check the codes again and it's still a Cylinder 6 misfire. Tried clearing the code again and start the engine up and it'll do the same thing again. Put in a second new injector and coded it and made no difference...

I was looking into the DME issue. Time to take it out and send out to get it diagnosed?

[Dormermike]

There was a guy recently had a misfire and it was a broken spring but that misfired all the time, not intermittently.

No other codes?

Might be worth a look around bimmerprofs website for odd misfire scenarios.

Afaik a dud or dodgy mosfet can be intermittent.

Might be worth cracking out the multimeter and checking the mosfet and wiring, and that the ecu is not currently bathing in water.

Also have you considered a compression test...

[LKN624]

Originally Posted by Dormermike

There was a guy recently had a misfire and it was a broken spring but that misfired all the time, not intermittently.

No other codes?

Might be worth a look around bimmerprofs website for odd misfire scenarios.

Afaik a dud or dodgy mosfet can be intermittent.

Might be worth cracking out the multimeter and checking the mosfet and wiring, and that the ecu is not currently bathing in water.

Also have you considered a compression test...

I was thinking it was a stuck valve or something...might need to do a walnut blast.

No other codes, just Cyl 6 Misfire...

Yeah I did hear about a dodgy MOSFET in the DME, could be a possibility...did also check the white box and it's all dry in there.

Also just did a Compression Test. All between 195-205 psi...which is fantastic in my opinion so that is a relief I suppose!

I did however take out all of the plugs again and smelled them all. Looks like Cyl 4 Injector is leaking slightly as well, since it had some fuel smell on it.

[LKN624]

I took out my DME and it is a MDS81 Index 4...so I don't think its a DME issue, but still quote possibly be.

I will change out the Cyl 4 Injector this week with a new plug and see what it does.

[F31B48]

Originally Posted by LKN624

I took out my DME and it is a MDS81 Index 4...so I don't think its a DME issue, but still quote possibly be.

I will change out the Cyl 4 Injector this week with a new plug and see what it does.

There is a known issue with these engines where the misfire detection is incorrect. It will log a fault code for misfire cyl 6 in your case, but it will actually be a misfire in the cylinder that just fired previously, in this case cylinder 3 as the firing order is 1 5 3 6 2 4.
The Bimmerprofs website documents this problem in detail, and also has some other really good information. Try putting the new injector into cyl 3.

https://bimmerprofs.com/misfire-counters/

I was caught out by this issue with an N43. It had a misfire on cylinder 4 which turned out to be a misfire on cyl 3. A lot of time/money was wasted before i discovered this.

[LKN624]

Originally Posted by EvaBmw

There is a known issue with these engines where the misfire detection is incorrect. It will log a fault code for misfire cyl 6 in your case, but it will actually be a misfire in the cylinder that just fired previously, in this case cylinder 3 as the firing order is 1 5 3 6 2 4.
The Bimmerprofs website documents this problem in detail, and also has some other really good information. Try putting the new injector into cyl 3.

https://bimmerprofs.com/misfire-counters/

I was caught out by this issue with an N43. It had a misfire on cylinder 4 which turned out to be a misfire on cyl 3. A lot of time/money was wasted before i discovered this.

Wow that is very interesting...definitely could be the cause of my issue. I will replace Injector 4 and code it and see.

Meanwhile, I was reading where you had to reset the Adaptations on the DME AFTER you code the injectors. This was not included in any of the videos or DIY threads that I read. But, after doing so...the car runs perfectly fine now. Pretty smooth and no codes being thrown...

[F31B48]

Originally Posted by LKN624

Wow that is very interesting...definitely could be the cause of my issue. I will replace Injector 4 and code it and see.

Meanwhile, I was reading where you had to reset the Adaptations on the DME AFTER you code the injectors. This was not included in any of the videos or DIY threads that I read. But, after doing so...the car runs perfectly fine now. Pretty smooth and no codes being thrown...

It will be cylinder 3 injector that you need to replace not cylinder 4. You could try moving cylinder 3 injector to another cylinder first to verify this is the issue before buying a new one.

[LKN624]

Originally Posted by EvaBmw

It will be cylinder 3 injector that you need to replace not cylinder 4. You could try moving cylinder 3 injector to another cylinder first to verify this is the issue before buying a new one.

Yeah the thing is...smelling all of the spark plugs, the one in Cyl 4 smells like fuel, whereas Cyl 3 doesn't. Cyl 6 used to smell like fuel, but since replacing the injector its normal now.

[lee.j.hill]

Originally Posted by EvaBmw

There is a known issue with these engines where the misfire detection is incorrect. It will log a fault code for misfire cyl 6 in your case, but it will actually be a misfire in the cylinder that just fired previously, in this case cylinder 3 as the firing order is 1 5 3 6 2 4.
The Bimmerprofs website documents this problem in detail, and also has some other really good information. Try putting the new injector into cyl 3.

https://bimmerprofs.com/misfire-counters/

I was caught out by this issue with an N43. It had a misfire on cylinder 4 which turned out to be a misfire on cyl 3. A lot of time/money was wasted before i discovered this.

so if my car misfires on cylinder 4 would that be 1 ?

[F31B48]

Originally Posted by lee.j.hill

so if my car misfires on cylinder 4 would that be 1 ?

It depends. Do you have an n43 or n53?

[rkwdev]

Originally Posted by EvaBmw

It depends. Do you have an n43 or n53?

Hey, my N53 sometimes provides me with codes of misfiring on 5/6 cylinder and uneven run of 3rd cylinder. Is it possible that 3rd injector is bad and 1 one too instead of injectors in cylinders 5/6?