[danfratamico]

Here is some history on my situation. Car is a 2007 BMW 335xi with the N54 engine:

• About a year ago, all injectors & seals were replaced with index 9 (I bought them very cheap used), coded via INPA, and that solved my issue of severe misfiring. This did not solve my other issue of rough starting and bubbling only a few seconds after starting the engine.
• In hoping to fix the bubbling, I bought another used index 9 injector for cylinder 1 a few days ago. The plug in that cylinder was the blackest I have ever seen a plug and when I took the injector out, the tip was very black too. I cleaned the plug with alcohol, cleaned the new injector tip, new seal, installed, and coded.
• The car now runs worse after it warms up and ONLY at idle or very slow speeds, such as letting the car idle in D, it almost feels like the tranny is slipping but it's definitely mini misfires.
• At idle, the RPMs will fluctuate a bit, but there's that constant shaking feeling in the seat. I bought a new coil for cylinder 1, did not help.

My question is, what are the chances of that new injector also being bad? Could it be cylinder 1 spark plug? I have NGK 95770s in the car that I gapped and installed 6 months ago.

[NFiftyWon]

Get some codes. Probably a bad coil pack.

[danfratamico]

Originally Posted by NFiftyWon

Get some codes. Probably a bad coil pack.

I bought a new coil for the cylinder with the black plug, didn't help.

[NFiftyWon]

Originally Posted by danfratamico

I bought a new coil for the cylinder with the black plug, didn't help.

Check all the cylinders.

[danfratamico]

Originally Posted by NFiftyWon

Check all the cylinders.

Yep, already did. Cylinders 2-6 the plugs look fine. It's only cylinder 1 which has the fuel smell and is super black with carbon deposits. I'm thinking I must have put in a bad injector.

[NFiftyWon]

Originally Posted by danfratamico

Yep, already did. Cylinders 2-6 the plugs look fine. It's only cylinder 1 which has the fuel smell and is super black with carbon deposits. I'm thinking I must have put in a bad injector.

My car is port injected so cant really help you there.. would still recommend getting some codes before spending any coin

[arkie6]

Probably got another bad leaking index 9 fuel injector. There is a trick where you flip the fuel rail and connect all of the injectors to the fuel rail pointed up outside of the engine without the electrical connectors connected. Then you try to start the car which builds fuel system pressure and you can visually verify if any injectors are leaking while under pressure. I've seen some youtube videos showing this procedure.

[danfratamico]

Originally Posted by arkie6

Probably got another bad leaking index 9 fuel injector. There is a trick where you flip the fuel rail and connect all of the injectors to the fuel rail pointed up outside of the engine without the electrical connectors connected. Then you try to start the car which builds fuel system pressure and you can visually verify if any injectors are leaking while under pressure. I've seen some youtube videos showing this procedure.

Just installed another index 9 injector, car is running worse now. How many bad injectors can I be buying? I've exhausted most of the common issues. Threw in a a new plug and coil, same thing.

[arkie6]

Have you pulled your spark plugs after the engine has been shutdown and cooled down to so see if any are wet with fuel?

People have removed index 9 injectors because they are bad. All you are doing is buying other peoples discards. How much do these used injectors cost anyway? I may need to see if I can sell my old ones.

[danfratamico]

Originally Posted by arkie6

Have you pulled your spark plugs after the engine has been shutdown and cooled down to so see if any are wet with fuel?

People have removed index 9 injectors because they are bad. All you are doing is buying other peoples discards. How much do these used injectors cost anyway? I may need to see if I can sell my old ones.

Cylinder 1 spark plug is the only one which is consistently wet when engine is off. After running, it's covered in black soot. I have been paying about $25 per used index 9 injector. The one seller on eBay refunded me and said of the 6 injectors he sold, I was the only one to report an issue which leads me to believe maybe something else is going on.

[dpaul]

FWIW, index 9 injectors are widely reported to be the worst.

My personal experience is that a dealer replaced all 6 of my injectors with index 9 at the very end of my warranty period. It solved the problem initially but all of the new ones failed within 12-18 months. Index 12 seems to be a longer term solution.

It would not surprise me to find you've gotten several bad used index 9 injectors

[danfratamico]

I performed a compression test and here are my results. Cylinder 1 was having the misfires:

Cylinder 1 - 155/160
Cylinder 2 - 180
Cylinder 3 - 180
Cylinder 4 - 180
Cylinder 5 - 180
Cylinder 6 - 180

I read online that a 10-20% variance in results is OK. Anything above 20% is cause for concern. Cylinder 1's result of 160 is only ~11% variance from my other cylinders. Is this variance high enough to try a leak down test?

As a test, I moved cylinder 1's injector to cylinder 2. As expected, cylinder 2's spark plug built up quite a bit of carbon and was wet, so that tells me that injector is bad. But what's confusing me is that I am also getting a code for misfires on cylinder 1 even after the injector swap (the injector i swapped into cylinder 1 was working fine in cylinder 2). Could my plug be bad in cylinder 1? I also moved coils around, the misfire didn't follow the coil.

[Liquid_Arthur]

I'm having similar issues. Will stay tuned...

[danfratamico]

Originally Posted by Liquid_Arthur

I'm having similar issues. Will stay tuned...

Did you perform a compression test? If so, what were your cylinder values?

[macheff03]

Had a similar problem on my n52 and for what it's worth I'll post it here, and how I fixed it

Though it's not completely gone it is much better than it once was

So, I cleaned my VANOS solenoids, yes that's all I did and it made the problem say, 80% better than what it was before.

Not to mention the only cost was the $4 I paid for the engine degreaser and it only took me around 30 minutes or so.

Now, I'm not saying this is even remotely close to the problem but it did help mine so I thought I'd put in my two cents

Either way, good luck getting to the bottom of this!

EDIT: Was also just reading another thread and someone said bad gas was a problem for them

[danfratamico]

Update: Ordered new seals, decouplers, and 6 used index 11 injectors on eBay. I bought the injectors at a great price of $140 total. Great price especially since index 11 and 12 are nearly identical and don't have the problems the previous indexes had.

[sparky1]

while you're in there, clean your MAP sensor ontop of the intake manifold. I just cleaned mine this weekend after having some stumbling idle issues and it is running much better afterwards

[danfratamico]

Originally Posted by sparky1

while you're in there, clean your MAP sensor ontop of the intake manifold. I just cleaned mine this weekend after having some stumbling idle issues and it is running much better afterwards

Thanks, definitely will. What should I use, mass air flow sensor cleaner spray? Do you also recommend spraying down the VANOS solenoid as well?

[sparky1]

Originally Posted by danfratamico

Thanks, definitely will. What should I use, mass air flow sensor cleaner spray? Do you also recommend spraying down the VANOS solenoid as well?

it wouldn't hurt to clean the VANOS solenoids as well

and I used MAF cleaner on mine, i'd imagine that's safer than brake cleaner on a sensor like that.

[arkie6]

Originally Posted by danfratamico

Update: Ordered new seals, decouplers, and 6 used index 11 injectors on eBay. I bought the injectors at a great price of $140 total. Great price especially since index 11 and 12 are nearly identical and don't have the problems the previous indexes had.

Why would someone remove index 11 injectors in good condition?

There are a lot of Chinese cloned BMW parts on ebay, so buyer beware. If the price seems too good to be true, it probably is. And if the energy and flow rate values are identical on 2 or more of your injectors, I would be highly suspicious that they are cloned injectors and the energy and flow rate values are meaningless for coding to your DME.

[Bimmer_Engineer]

Originally Posted by arkie6

Why would someone remove index 11 injectors in good condition?

There are a lot of Chinese cloned BMW parts on ebay, so buyer beware. If the price seems too good to be true, it probably is. And if the energy and flow rate values are identical on 2 or more of your injectors, I would be highly suspicious that they are cloned injectors and the energy and flow rate values are meaningless for coding to your DME.

+1 to this. Also you did a compression test and 5 of 6 cylinders are identical and one is 20 psi low. I'm not an expert but I suspect that's your problem.

[danfratamico]

Originally Posted by Bimmer_Engineer

+1 to this. Also you did a compression test and 5 of 6 cylinders are identical and one is 20 psi low. I'm not an expert but I suspect that's your problem.

Installed the injectors today, and it seems like my starts are better but the car has a rough idle with miniature misfires. Other than that, the car pulls great and I have no other issues. I'm thinking I'm due for a walnut shell blasting. I bought the car with 65k and it has 102k now. Not sure if it has ever been done. They looked pretty build up with crud last time I took a peek at cylinder 1's valves. Could that cause a rough idle?