[panchofarrera]

Hello everyone, I am new to the forum. I've had BMW's for a while, and have never faced so many issues as I have in my 335xi (2008 BMW 335xi Coupe). So, now I am dealing with some RPM fluctuations after cold starts (not always) and vibration or hiccups at idle. Here's what I know:

1) No codes
2) I just cleaned carbon deposits in the valves, didn't fix it (although it accelerates much better now)
3) Spark plugs are new
4) Ignition coils are new (BOSCH)
5) Inpa shows the LPFP Working at 5000 as it should
6) 3 of my injectors (cylinders 1, 3 and 6) are Index 5, the rest are index 9.

I have heard that you shouldn't use different index injectors in these engines, and also that sometimes the injectors get dirty or leak causing the misfires. I have ordered 3 re-manufactured factory Index 9 (3 year warranty) injectors to replace the index 5's, and 6 o-rings to replace all the gaskets in all the injectors. I also will be cleaning the carbon build up on them if any.

Does this sound like it could potentially fix my issue? I realize that getting 6 Index 12 injectors would be the best way to do this, but the difference in price is ridiculous. Are the o-rings worth changing? Any experience/advice is highly appreciated

You're going to have to, at the very least, want to read the plugs in each cylinder first. You can't diagnose an issue just by going off of index value alone.

There's no sense in replacing older injectors for newer injectors just for the sake of doing so; especially for Index 9's. Most in the know will likely tell you those had the most problems out of all of them.

Are you tuned? If so, now would be a good time to pull a log.

[335e92tx]

Originally Posted by FCobra94

You're going to have to, at the very least, want to read the plugs in each cylinder first. You can't diagnose an issue just by going off of index value alone.

There's no sense in replacing older injectors for newer injectors just for the sake of doing so; especially for Index 9's. Most in the know will likely tell you those had the most problems out of all of them.

Are you tuned? If so, now would be a good time to pull a log.

yep - boom +1

This problem just start?
Miles ?
You always owned it or get it recently??

ARe you getting any abnormal idle when it starts first thing cold (after 8hrs min )?
Injs normally will leakdown overnight and dump raw fuel. If your not smelling raw fuel in the morning its less likely an inj prob... not for certain... but possible..

Or, what other symptoms you got - only idle. Can you generate a log ??.. include 1400 rpm light load.
Can IPNA show individual injector voltage loads? Might be some variation between the 6 that is bank to bank.

[panchofarrera]

Thanks for the responses!
To answer your questions:

1) I purchased the car a month ago, 130k miles.
2) It has had this problem since I got it, and for more than a year according to previous owner.
3)The shaking is worst on cold start, I do smell a gassy smell, but cannot be 100% sure. I get hiccups on red lights under regular driving. The car begins to feel better when it reaches operating temperature.
4) I have verified INPA to make sure all injectors are coded correctly and working at the right voltage and flow (I'm not sure if this is what you meant).

5) Again, no error codes from INPA, no values seem to be outside of the ordinary except for the INJECTOR ADAPTATIONS which show between 1-2% and show a "!" sign next to the values.

Is there a way to run a more detailed log in INPA that could reveal which injector is the problem? I am also getting around 14mpg in city driving and 23 in highway which seems low.

[panchofarrera]

And no, I am not tuned.

[335e92tx]

Originally Posted by panchofarrera

Thanks for the responses!
To answer your questions:

1) I purchased the car a month ago, 130k miles.
2) It has had this problem since I got it, and for more than a year according to previous owner.
3)The shaking is worst on cold start, I do smell a gassy smell, but cannot be 100% sure. I get hiccups on red lights under regular driving. The car begins to feel better when it reaches operating temperature.
4) I have verified INPA to make sure all injectors are coded correctly and working at the right voltage and flow (I'm not sure if this is what you meant).

5) Again, no error codes from INPA, no values seem to be outside of the ordinary except for the INJECTOR ADAPTATIONS which show between 1-2% and show a "!" sign next to the values.

Is there a way to run a more detailed log in INPA that could reveal which injector is the problem? I am also getting around 14mpg in city driving and 23 in highway which seems low.

all cyls? or just a specific bank

if all, and 120K plus miles, Id do all injs at once. Especially if you plan on modding it. And intake cleaning.

Baseline the motor, Full maint, and monitor for fluid use. Then start to lean on it.

Not sure myself.. dont have much experience.. more bavtech diag.

[panchofarrera]

All cylinders show injector adaptation values between 1-2%. Do you know what these values should be showing?
I have cleaned the intake and valves. Got a LOT of carbon out of the system.

[335e92tx]

Originally Posted by panchofarrera

All cylinders show injector adaptation values between 1-2%. Do you know what these values should be showing?
I have cleaned the intake and valves. Got a LOT of carbon out of the system.

no, not specifically. I can see if bavtech shows. I Dont think so. I think someone here might be able to check on a healthy motor..

[langsbr]

How are your fuel trims? If you don't have some kind of issue, be it wacky fuel trims, or bad driveability, o2 codes, or something - i think it's unlikely to be your injectors. If they are leaking, they will throw off your fuel trims. if they are leaking bad enough, they will throw a code.

My bank 2 have been giving me an issue for a few months - lots of O2 sensor line faults, and mixture codes. I just got some used index 8s (my bad ones are index 8s too) from someone that said he replaced his thinking that was causing a misfire, but the misfire remained. I took a chance and used them and installed new couplers and seals and no more codes.

I think it is unlikely that a rough idle (only) is injectors. I'd expect some other symptoms, regardless of how minor.

EDIT - based on your additional info regarding the issues at stoplights - it definitely could be injectors. I have heard though, as mentioned earlier - that index 9s were the worst, which is why they are the most common ones found online. If you do replace them - make sure to do the teflon seals - not doing so is risking your motor. I got the Precision raceworks tool - it works great!

[feuer]

Originally Posted by panchofarrera

2) It has had this problem since I got it, and for more than a year according to previous owner.

I would stop driving ans send oil to lab ASAP. If injector/s has been leaking for this long that engine is probably dying. In the mean time while you wait for results check with your INPA if these injectors are coded properly.

[panchofarrera]

Originally Posted by feuer

I would stop driving ans send oil to lab ASAP. If injector/s has been leaking for this long that engine is probably dying. In the mean time while you wait for results check with your INPA if these injectors are coded properly.

Would that kind of serious engine damage be possible if I am not seeing any other symptoms? The car accelerates very smoothly, consumes NO oil whatsoever, doesn't smoke, and really feels like new when moving.

[panchofarrera]

UPDATE: I just started the car after it sitting for about 20 hours. Starts after the first crank (as always), RPMs raise up to about 1100 (as always), but no misfires or hiccups or fuel smell at all. It is my logic that if an injector is leaking, I would get shaking EVERY time I let the car sit and start it correct?
About a week ago, I reset all adaptations in the car. Could this be the effect of the car re adapting?

[feuer]

Originally Posted by panchofarrera

Would that kind of serious engine damage be possible if I am not seeing any other symptoms? The car accelerates very smoothly, consumes NO oil whatsoever, doesn't smoke, and really feels like new when moving.

Bearing wear, especial cyl 1 & 2.

[panchofarrera]

Originally Posted by feuer

Bearing wear, especial cyl 1 & 2.

If that was the case. What can be done to slow down damage? Would switching to 20w60 help? I am running 10w40 castrol edge.

Changing oil weight/type/brand/color is not a proper fix.

Figure out if you have a hardware issue FIRST, then proceed accordingly.

[feuer]

Originally Posted by panchofarrera

If that was the case. What can be done to slow down damage? Would switching to 20w60 help? I am running 10w40 castrol edge.

Mignt not be the case. I certainly hope not. You said problem persisted for over a year, you smell gas and experiencing rough idle. If it's/was injector leaking for long periods the damage is there and switching oil grade won't make significant benifitial long term difference.

[panchofarrera]

Originally Posted by feuer

Mignt not be the case. I certainly hope not. You said problem persisted for over a year, you smell gas and experiencing rough idle. If it's/was injector leaking for long periods the damage is there and switching oil grade won't make significant benifitial long term difference.

Ok so in order to determine whether one or more injectors is bad, is there any way to diagnose besides just changing all of them and seeing if it makes a difference? Again, no codes, no roughness values out of the ordinary.

[335e92tx]

Did you do the last OC yourself? Did it smell like fuel. closed loop motors keep oil pretty clean (at least of other hydrocarbons ) , espeically since they run at 220degrees plus..


An oil sample will help with baselining engine. Dont change oil vis. That rarely turns out well - BMW bearings dont give a lot of margin there..

[feuer]

Originally Posted by panchofarrera

Ok so in order to determine whether one or more injectors is bad, is there any way to diagnose besides just changing all of them and seeing if it makes a difference? Again, no codes, no roughness values out of the ordinary.

Let the car sit over hight with disconnected battery. In the morning first disconnect the fuel rail. If no flue sprays under pressure chances are you have leaking injector/s. Start removing the spark plugs. If you find spark plug with black sooth that smells like gas you found the leaking injector.

[panchofarrera]

Originally Posted by 335e92tx

Did you do the last OC yourself? Did it smell like fuel. closed loop motors keep oil pretty clean (at least of other hydrocarbons ) , espeically since they run at 220degrees plus..


An oil sample will help with baselining engine. Dont change oil vis. That rarely turns out well - BMW bearings dont give a lot of margin there..

I did change my oil when I bought the car. The oil looked and smelled healthy. I didn't notice anything out of the ordinary in the oil. And it was overdue for a change by 2k miles according to the previous owner, I can't be sure though.

The rough idle hiccups do not feel terrible or constant. Sometimes it idles smooth.
I must say I changed my sparkplugs with some BOSCH I found in amazon in an attempt to fix this issue. The car had brand new Bosch plugs that looked just like mine. Ive heard that these could be the problem although they are OEM.

I have INPA, is there anything I can do with that to diagnose injectors?

[panchofarrera]

Originally Posted by feuer

Let the car sit over hight with disconnected battery. In the morning first disconnect the fuel rail. If no flue sprays under pressure chances are you have leaking injector/s. Start removing the spark plugs. If you find spark plug with black sooth that smells like gas you found the leaking injector.

I will definitely check this out tomorrow !

[335e92tx]

Originally Posted by feuer

Let the car sit over hight with disconnected battery. In the morning first disconnect the fuel rail. If no flue sprays under pressure chances are you have leaking injector/s. Start removing the spark plugs. If you find spark plug with black sooth that smells like gas you found the leaking injector.

Yep, not a bad plan.. should be plenty residual pressure. and if there isnt there will likely be obvious signs of where it went.