[achien]

Originally Posted by Syndicategt

As said before, walnut shell blasting will do nothing for misfires, it will only smooth out your idle if that is rough.

There is something else going on with these cars lately that no one has a clue about. It's not your typical plug/coil/injector/hpfp problem. My guess is, there is something wrong with the cams/VANOS. The same thing happened to my car before I got rid of it, it was misfiring and nothing I did could fix it and I ran though the gambit (including walnut shell blasting). If you look around the forums, this problem is happening rather frequently and seems to increase by the day. The dealer is just throwing darts at the board with guesses (DME, injectors, cleaning, etc.) but really don't know the issue at hand.

Not true, at least for my car.

I did not experienced rough idle at all. Only when I rev the engine above 5k did the problem "engine light" came up.

Every car's problem could be different (plugs, coils, injectors, carbon, vanos), I would not over generalize the problem.

[Syndicategt]

Originally Posted by achien

Every car's problem could be different (plugs, coils, injectors, carbon, vanos), I would not over generalize the problem.

Read again please, I'm not over generalizing anything. Just stating there has been a large increase with misfires/rough idles.

[bryce]

Originally Posted by Syndicategt

As said before, walnut shell blasting will do nothing for misfires, it will only smooth out your idle if that is rough.

There is something else going on with these cars lately that no one has a clue about. It's not your typical plug/coil/injector/hpfp problem. My guess is, there is something wrong with the cams/VANOS. The same thing happened to my car before I got rid of it, it was misfiring and nothing I did could fix it and I ran though the gambit (including walnut shell blasting). If you look around the forums, this problem is happening rather frequently and seems to increase by the day. The dealer is just throwing darts at the board with guesses (DME, injectors, cleaning, etc.) but really don't know the issue at hand.

i think a lot of it can be blamed on carbon build-up. i've seen a lot of people post positive results to odd misfires/idles after getting their valves cleaned. like OP stated below

Originally Posted by achien

Not true, at least for my car.

I did not experienced rough idle at all. Only when I rev the engine above 5k did the problem "engine light" came up.

Every car's problem could be different (plugs, coils, injectors, carbon, vanos), I would not over generalize the problem.

[Syndicategt]

Originally Posted by bryce

i think a lot of it can be blamed on carbon build-up. i've seen a lot of people post positive results to odd misfires/idles after getting their valves cleaned. like OP stated below

But the only thing valve cleanign will do is make the air less turbulent and flow more evenly. Unless you have so much carbon build-up the vavles are not seating properly or it's blocking it entirely, I don't see how this can cause a misfire by just cleaning them. Do I agree with cleaning, hell yea I do, it made my car feel brand new.....I'm just hesitant to have people think this will cure their misfires.

[Mangler]

Originally Posted by Syndicategt

But the only thing valve cleanign will do is make the air less turbulent and flow more evenly. Unless you have so much carbon build-up the vavles are not seating properly or it's blocking it entirely, I don't see how this can cause a misfire by just cleaning them. Do I agree with cleaning, hell yea I do, it made my car feel brand new.....I'm just hesitant to have people think this will cure their misfires.

What if the carbon build up is creating a disturbance in the flow to where it is hindering the swirl in the combustion chamber? Therefore propagating as suboptimal flame front and poor performance?

T

[bryce]

Originally Posted by Syndicategt

But the only thing valve cleanign will do is make the air less turbulent and flow more evenly. Unless you have so much carbon build-up the vavles are not seating properly or it's blocking it entirely, I don't see how this can cause a misfire by just cleaning them. Do I agree with cleaning, hell yea I do, it made my car feel brand new.....I'm just hesitant to have people think this will cure their misfires.

Originally Posted by Mangler

What if the carbon build up is creating a disturbance in the flow to where it is hindering the swirl in the combustion chamber? Therefore propagating as suboptimal flame front and poor performance?

T

it's a little too technical for me as to why, but for some reason, carbon build up can and will cause misfires.

[Mangler]

Should know if the carbon buildup is the issue or not in about 30min. Went by the dealer and he was on the last one and they are all spotless now. He took some pics of them before he started and it was terrible. He had chunks that looked like rubber buildup at the track in the corners from tires. I could not believe the car even ran like that.

T

[Mangler]

Fixed. Carbon buildup. Corrected under warranty.

T

[tenxaday]

I'm having these same problems. My dealer said they do not do carbon clean up on my 335. He told me to use Techron. Which i know doesnt work because i have been dealing with this problem for months.

[MDORPHN]

Originally Posted by tenxaday

I'm having these same problems. My dealer said they do not do carbon clean up on my 335. He told me to use Techron. Which i know doesnt work because i have been dealing with this problem for months.

That dealer is an idiot. I'd find another quickly!

Neil

[n54door]

Originally Posted by Syndicategt

But the only thing valve cleanign will do is make the air less turbulent and flow more evenly. Unless you have so much carbon build-up the vavles are not seating properly or it's blocking it entirely, I don't see how this can cause a misfire by just cleaning them. Do I agree with cleaning, hell yea I do, it made my car feel brand new.....I'm just hesitant to have people think this will cure their misfires.

Consider this, when you have excess carbon deposits on the valves it not only effects the air flow, but consequently the air friction increases heat, and the material itself can also absorb and radiate more heat.

More heat = more misfires.

[Tzu]

Not sure why dealers and some people refuse to beleive carbon cleaning is unnecessary. I've done it 3 times so far and I'm at 110k km. Worth it every time.

[koss2010]

Guys I'm having the same problem, on my morning drive my car started to hesitate or stutter with a heavy foot (not even flooring it). The "service engine soon" light came on and now I'm starting to get worried because I just bought the car. Is there a way to pull the "service engine soon" code? The odd thing is after 10 mins the light went off and the car just went back to normal. :/

[agustincuenca]

Reviving this old one. I have the exact same issue as described in OP. Hesitation/hiccups between 3,000 and 4,200/4,500 RPM and full power/torque after that. No codes, nothing.
Car is a 2008 335i with 126k miles.

Injectors new since 110k mls
Coils new (Eldor) and Sparks (NGK) at 118k mls
Walnut blasted at 124k mls
two new boost solenoids at 124k mls
vacuum tested, no leaks at teh 124k mls service.

Do you still think it can be walnut blasting was not done properly?

What I will do next weekend is: new sparks, Bosch, and installing back stock airbox (I think my dual cones are bad even though I cleaned them). If this doesn't fix it I will take it to my indy shop.

[Sgop335]

Originally Posted by agustincuenca

Reviving this old one. I have the exact same issue as described in OP. Hesitation/hiccups between 3,000 and 4,200/4,500 RPM and full power/torque after that. No codes, nothing.
Car is a 2008 335i with 126k miles.

Injectors new since 110k mls
Coils new (Eldor) and Sparks (NGK) at 118k mls
Walnut blasted at 124k mls
two new boost solenoids at 124k mls
vacuum tested, no leaks at teh 124k mls service.

Do you still think it can be walnut blasting was not done properly?

What I will do next weekend is: new sparks, Bosch, and installing back stock airbox (I think my dual cones are bad even though I cleaned them). If this doesn't fix it I will take it to my indy shop.

What about the vanos solenoids, original?

[agustincuenca]

Originally Posted by Sgop335

What about the vanos solenoids, original?

thanks for the input!
I haven't changed those for sure and I would bet are original. Can that be the culprit for stuttering on hard accel between 3k to 4.5k rpms?

[Sgop335]

Originally Posted by agustincuenca

thanks for the input!
I haven't changed those for sure and I would bet are original. Can that be the culprit for stuttering on hard accel between 3k to 4.5k rpms?

If they are original, it is a good bet to replace them (at that miles) even w no codes. Some even clean them but in your case replace may be better. A tip - if you are replacing DONT buy the Chinese aftermarket ones. I just bought two for my new to me 535i with 108k miles. Two for $120, made in germany. Those vanos solenoids are a big deal to the engine operation.

[parksjm7]

Originally Posted by Sgop335

if you are replacing DONT buy the Chinese aftermarket ones.

I installed a pair of cheap solenoids for ~$25 a few days ago after considering the ways the solenoids can go south; do you have any horror stories / examples of failed cheap solenoids that I'm unaware of? Not trolling or otherwise trying to discredit - legitimately looking for examples of failed cheap solenoids and consequences. Thanks

[Sgop335]

Originally Posted by parksjm7

I installed a pair of cheap solenoids for ~$25 a few days ago after considering the ways the solenoids can go south; do you have any horror stories / examples of failed cheap solenoids that I'm unaware of? Not trolling or otherwise trying to discredit - legitimately looking for examples of failed cheap solenoids and consequences. Thanks

No problem - As is always the case w cheap aftermarket parts it will be hit or miss. That is the same reason why there will be proponents and opponents. Look at some amazon reviews. Question is how will yours turn out and how long will it last? In my opinion not worth to chance that on a critical component...say you are on a long road trip and not to mention its tuned.

[agustincuenca]

Originally Posted by Sgop335

No problem - As is always the case w cheap aftermarket parts it will be hit or miss. That is the same reason why there will be proponents and opponents. Look at some amazon reviews. Question is how will yours turn out and how long will it last? In my opinion not worth to chance that on a critical component...say you are on a long road trip and not to mention its tuned.

thanks again! I know change them is quite easy, but does it requires any coding other than out with the old in with the new?

[arkie6]

I would check and clean the VANOS solenoid oil supply filters / non-return valves before I went to the expense of replacing the VANOS solenoids.

[agustincuenca]

Originally Posted by Sgop335

If they are original, it is a good bet to replace them (at that miles) even w no codes. Some even clean them but in your case replace may be better. A tip - if you are replacing DONT buy the Chinese aftermarket ones. I just bought two for my new to me 535i with 108k miles. Two for $120, made in germany. Those vanos solenoids are a big deal to the engine operation.

ok, I will see changing them. I did sparks and while doing that I took them out and clean them, but car still doing the same...I'm gonna try the different COBB maps (which I don't think will change a thing) and worst case scenario will take it to my indy