[MichaelP]

Has anyone had any issues with index 12 injectors failing?

I have been chasing down a misfire here are they symptoms.

My 335i 6 my has 109k just changed plugs and coils and still getting the misfire on cylinder 4. The ses light will come and go but when it comes on the car runs extremely rough especially at low rpm load. If you go full throttle from 2k rpm especially in the higher gears is the worst.


I had the injectors replaced by BMW at 72k with all index 12 so they only have about 37k on them.

I was going to do a walnut blast to see if that fixes it but then today I noticed that my average mpg went to 99.9 (the actual reading still works properly) which made me think it might be something fuel related.

Car is stock. Any thoughts?

[Boland01]

Let the car sit over night, pull plug #4 and see if it smells like gas and how it looks. That might help guide you in the right direction.

On our 2007 335i I changed the plugs, coils, injectors and mosfets. After a while the car still had misfires. Turned out the MDS80 DME was bad. Ended up having to get a new DME (MDS81) and the car has been great since.

I feel your frustration. All you can do is to start to eliminate possible culprits.

[HawkeyeGeoff]

Originally Posted by Boland01

Let the car sit over night, pull plug #4 and see if it smells like gas and how it looks. That might help guide you in the right direction.

On our 2007 335i I changed the plugs, coils, injectors and mosfets. After a while the car still had misfires. Turned out the MDS80 DME was bad. Ended up having to get a new DME (MDS81) and the car has been great since.

I feel your frustration. All you can do is to start to eliminate possible culprits.

+1

[Ballistic]

Please stop spreading wrong information. Fuel will evaporate if you keep it sitting for a night. Fuel pressure drops very quick and letting it sit that long does not do anything.

Easy check for big leaks: Run the car around the block, hit 3000rpm (to get max fuel pressure) and then let it sit for 30min. Then start the car. If it stumbles upon starting then you have a big leak or all of them are leaking. Replace all injectors.

Harder more detailed check: Run the car around the block, hit 3000rpm (to get max fuel pressure) and then let it sit for 30min. Pull plug and check if they are wet. Use flashlight and try to see if piston is still wet too. Compare results between cilinders.

Originally Posted by Ballistic

Please stop spreading wrong information. Fuel will evaporate if you keep it sitting for a night. Fuel pressure drops very quick and letting it sit that long does not do anything.

FALSE

Reading plugs as a proper initial diagnosis is exactly where one should start. If the injector is leaking enough fuel to cause a stumble, that amount of fuel will NOT evaporate in an ~8 hour period.

Not to mention, plugs that share a cylinder with a leaky injector will look completely different from those with an injector that is in proper order.

In your "around the block scenario" an injector would literally have to be pissing fuel at the rate of a race horse to notice that much deviation from cylinder to cylinder within such a short time frame.

[MichaelP]

Thanks for the tips so far. When troubleshooting last night I was pulling plugs in and out to try and eliminate it being a "spark" issue. None of them were wet or had any fuel smell to them. Heres what they looked like

[fordbaxter]

When an index 12 injector failed in my car it would stumble hard upon idle and when under high load. I let it sit overnight and when I took the plug out on that cylinder it was obvious where the gas was leaking from the injector onto the piston.

Normally I would start looking at injectors of the cylinders with the dirtiest plugs, but honestly, if there isn't even a hint of fuel smell on any of the plugs, there might be something else going on here.

How soon after the injectors were installed did the misfires start?

This might be a stretch, but we've all seen examples of techs @ stealerships forgetting to put decoupler elements, etc. on injectors during install (worse case scenario).

If I were you, I'd buy an injector seal tool, pull all the injectors, check to make sure the decouplers are all there, check/photograph the tips of the injectors, and replace the seals while you're in there before reinstalling them. That shouldn't take too much time or cost a lot of money and eliminate the variable of there being an issue with injector install, or even worse, the head itself.

[Ballistic]

Originally Posted by FCobra94

FALSE

Reading plugs as a proper initial diagnosis is exactly where one should start. If bla
bla
bla bla
.

Stop talking to get things your way and start reading what we are on about.


In this topic we are talking about a injector leak test and checking if things are wet in the cylinder. People are suggesting letting things sit overnight which is not a good idea because it WILL evaporate or leak down along the piston rings.

There is nothing wrong with what you are saying but this only relates to combustion.
"that amount of fuel will NOT evaporate in an ~8 hour period" Are you nuts? YES IT WIL! Specially if the valves of that cilinder are open. Cruising fuel pressures are around 600psi and only when flooring it the pressures goes to 2500+ psi. Before you parked your car and turned it off, the pressure is already down way below 500psi and will drop until there are barely any pressure left. At least not enough for the injector to be necessarily/possible leaking.
No leaking will happen the rest of the night. In the morning it will start and run fine (depends on how far along the injectors are ofcourse)

The most accurate test is testing it before anything can leak/evaporate. Which is 30min after performing a drive.

I suggest you remove your, to this topic, unrelated post.

@MichaelP
As your post confirms; you don't see much after performing the test as others suggested. Don't believe everything you read on the forums. Your plugs might have been "cleaned" by a leaking injector and cannot give you a proper combustion reading this way.
Try the method i suggested earlier. If that does not show any wet plugs/piston then you can be pretty sure the injectors are not the problem.

[Jeff@TopGearSolutions]

It's actually common for these injectors to leak, especially after the car sits overnight though. I understand what you're saying too but when these cars sit overnight with a leaking injector, the fuel pools in the cylinder and when you go to start the car in the morning the car typically stumbles and smells of unburnt fuel.

[Ballistic]

Jeff: I have a lot of experience with leaking piezo injectors. I have never had a car with bad injectors start bad in the morning. The morning start is the only start that goes OK on bad injectors.
What you are saying is simply not the case. If there really is a leak, most of the fuel will leak out as soon as you turn it off when the pressure is still high. Waiting more then an hour is not a good diagnose for this case because all pressure is lost anyway.

Dropping the mic now. I just want you guys to get correct information so you all can make a proper diagnose when you encounter this issue.

Originally Posted by Ballistic

Stop talking to get things your way and start reading what we are on about.

If you're that interested in results down to the nano second, the easiest/best place to start is to obviously pull a log first. Working on hot engines is no fun anyway

Going off your experience, you are also likely the only person in existence to not experience rough starts with bad injectors present...someone call Braco the Gazer, we have found his replacement!!

[litxus]

Originally Posted by MichaelP

Has anyone had any issues with index 12 injectors failing?

I have been chasing down a misfire here are they symptoms.

My 335i 6 my has 109k just changed plugs and coils and still getting the misfire on cylinder 4. The ses light will come and go but when it comes on the car runs extremely rough especially at low rpm load. If you go full throttle from 2k rpm especially in the higher gears is the worst.


I had the injectors replaced by BMW at 72k with all index 12 so they only have about 37k on them.

I was going to do a walnut blast to see if that fixes it but then today I noticed that my average mpg went to 99.9 (the actual reading still works properly) which made me think it might be something fuel related.

Car is stock. Any thoughts?

Yes, I had one of my index 12 injectors fail at around 39k miles or so, but under 40k for sure. How did I know, I swapped spark plugs, coils, and then I swapped injector bingo (swapped with an old one I had). Initially, I would get stumble misfire only sometimes, but as the time passed it became worse (especially when cold) and then it started doing it all the time. So yes index 12 injectors do fail as well, and I was running MHD Stage 1+ pretty much all the time. Next injector that fails I'm getting at FCP euro, as I believe they have "lifetime" warranty on all parts.

[Jeff@TopGearSolutions]

Originally Posted by Ballistic

Jeff: I have a lot of experience with leaking piezo injectors. I have never had a car with bad injectors start bad in the morning. The morning start is the only start that goes OK on bad injectors.
What you are saying is simply not the case. If there really is a leak, most of the fuel will leak out as soon as you turn it off when the pressure is still high. Waiting more then an hour is not a good diagnose for this case because all pressure is lost anyway.

Dropping the mic now. I just want you guys to get correct information so you all can make a proper diagnose when you encounter this issue.

Unfortunately your experience goes against the 1000's of people who've experienced injector leaks on this platform. It's with the utmost certainty if you wake up to a stumbling start up in the morning, that reeks of fuel, it is in fact an injector leaking. It's been remedied by people replacing their injectors and by no accident the problem was resolved. There really isn't much else it can be at that point.

I'm not going against your theory of testing the injectors within an hour of shut off time, that does seem logical. However a small minute leak may only rear it's head after everything cools. Remember, seals and other things expand when hot, after the vehicle cools, things can change - just playing devils advocate.

[georgelb]

Originally Posted by Ballistic

Jeff: I have a lot of experience with leaking piezo injectors. I have never had a car with bad injectors start bad in the morning. The morning start is the only start that goes OK on bad injectors.
What you are saying is simply not the case. If there really is a leak, most of the fuel will leak out as soon as you turn it off when the pressure is still high. Waiting more then an hour is not a good diagnose for this case because all pressure is lost anyway.

Dropping the mic now. I just want you guys to get correct information so you all can make a proper diagnose when you encounter this issue.

My cold starts got progressively rougher until recently the car would barely idle one morning, with a strong fuel smell. Root cause was a couple leaky injectors, with one of them leaking quite badly. Fix was to replace all six with index 12 injectors; I had a mix of index 3 and 9 in there.

My issues were only on a cold start; I didn't have any issues on a warm start (30 minutes after driving.)

[DailyN54]

OP for what its worth I kept getting misfires and also codes for injectors but not every time. After changing the injectors things seemed find for about a month then same thing. I went through this 4 times. Finally, a friend of mine suggested to have my Mosfets checked. I had new mosfets installed for $50 (PM me if you need the guys info) and havent had the issue in almost a year. Just another thing to look at that is cheap if these other methods dont help.

[Wolf 335]

Originally Posted by DailyN54

OP for what its worth I kept getting misfires and also codes for injectors but not every time. After changing the injectors things seemed find for about a month then same thing. I went through this 4 times. Finally, a friend of mine suggested to have my Mosfets checked. I had new mosfets installed for $50 (PM me if you need the guys info) and havent had the issue in almost a year. Just another thing to look at that is cheap if these other methods dont help.

Could you elaborate a bit on this?

[feuer]

Originally Posted by Wolf 335

Could you elaborate a bit on this?

Read here:
http://www.e90post.com/forums/showpo...&postcount=328
I replaced the shorted out mosfet witch cured the 30bb fault for broken DME however cyl#5 is still misfiring. Engine is running strong with different DME. Already verified that. Is either the DME, the new mosfet, my soldering skills, or combination of these. So it could be partially failed mofset.

[feuer]

Originally Posted by Ballistic

Stop talking to get things your way and start reading what we are on about. People are suggesting letting things sit overnight which is not a good idea because it WILL evaporate or leak down along the piston rings.

Just recently, few weeks ago, I had 135i for OFHG & OTHG replacement. In order to access one of the 3 bolts I had to loosen up and lift up the intake manifold. As soon as I pulled it up a strong gasoline smell hit me. Car was sitting in my garage for about 10-12hours. Guess what was I doing next?

[Boland01]

Originally Posted by Ballistic

Jeff: I have a lot of experience with leaking piezo injectors. I have never had a car with bad injectors start bad in the morning. The morning start is the only start that goes OK on bad injectors.
What you are saying is simply not the case. If there really is a leak, most of the fuel will leak out as soon as you turn it off when the pressure is still high. Waiting more then an hour is not a good diagnose for this case because all pressure is lost anyway.

Dropping the mic now. I just want you guys to get correct information so you all can make a proper diagnose when you encounter this issue.

Ballistic, whatever works for you- great. I can tell you from experience on an E92 335i I have pulled the plugs after letting it sit overnight and could smell fuel on the offending plug. In my case it did turn out that injector was sticking open. The advantage of pulling the plugs is it gives you a quick and easy snap shot on their condition and what might be going wrong.

[MichaelP]

***Update***

Got the car back from being walnut blasted yesterday. Night and day difference it idles perfectly smooth now and the low rpm hesitation/misfire underload is gone.

I still think it's kind of strange that it was only misfiring on 1 cylinder but so far that seems to have solved the issue. I'll keep everyone updated after I have put some more miles on it

[AWSAWS]

Originally Posted by MichaelP

***Update***

Got the car back from being walnut blasted yesterday. Night and day difference it idles perfectly smooth now and the low rpm hesitation/misfire underload is gone.

I still think it's kind of strange that it was only misfiring on 1 cylinder but so far that seems to have solved the issue. I'll keep everyone updated after I have put some more miles on it

I've read all the bickering above.

I'd recommend you pressure test the problematic cylinder at least. Better to do them all. See if the cylinder might be losing boost pressure and then running too rich, causing the misfire. It's a cheap and easy diagnostic to do.

If you keep getting a misfire on 4 then try swapping injector 4 with another. Re-coding injectors in INPA is very easy but you can run them without recoding while just seeing if the misfire follows the injector. Moving an injector is very easy to do. Just make sure you disconnect the battery. The pump intermittently primes the system and it'll end up shooting gas across the car when a fuel rail is unscrewed.

If all pressures come back as normal then you've eliminated one possible cause of misfires. What type of fuel are you running? Sometimes an in cylinder build up of deposits can create a hotspot that can increase misfires. You could try running a cleaner product with a high PEA content. Like redline si-1.

Best of luck!