[335i E92]

Hi

Having a nightmare with a rough idle (shakes & shivers) that started imeeditaly after changing my original plugs 18 months ago.

I've had 3 sets of Bosch & BMW oem plugs, 6 new coils and 6 new I injectors. Air leak test amongst many other parts with no fix.

My local Indy have advised to go back to basics and concentrate on the plugs as this was when the problems stared. They are looking to try a single prong NGK plug that some other 335i owners are using with success after miss fires on oem plugs. I believe they are from a 2008 mini cooper s and run cooler than oem plugs.

Here is a link to another thread that discuss them:

http://n54tech.com/forums/showthread.php?t=8470

Any experience or thoughts would be great.

[1000klr]

did you read the whole thread, because at the end he talks about his car shutting down and not restarting...might be better to stick with oem until there is another guinnea pig

[335i E92]

His car died due to a DME failure though, not related to the plugs. Unless I read it wrong?

[bryce]

i think dzenno is still banned at the moment, but he's been running the NGK plugs on his rb turbo setup for a while without issues.

[bryce]

here's the thread

[335i E92]

Originally Posted by bryce

here's the thread

Thanks, read the whole 9 pages!!

Seems he's using them without issue but it didn't solve his high boost misfire which is not same as my issue.

Anyone else have an opp on this?

[MKE_M3]

these cars have pretty poor idle, from my experience. I don't know how bad yours is, but you may just need to live with it.

[335i E92]

Originally Posted by jdemetry

these cars have pretty poor idle, from my experience. I don't know how bad yours is, but you may just need to live with it.

Its bad, at the lights the misfires shake the whole car and the idle then rises from 600 to 750 rpm. This only happened when I changed out the original plugs so it has to be a problem with plugs which is why I'm looking at as many plug options as poss. I've already tried thd bosch & BMW ones with all possible adaptation resest and it's stilljust as bad.

[ian2002525]

don't you think you also need to change coils??

[bryce]

Originally Posted by 335i E92

Hi

Having a nightmare with a rough idle (shakes & shivers) that started imeeditaly after changing my original plugs 18 months ago.

I've had 3 sets of Bosch & BMW oem plugs, 6 new coils and 6 new I injectors. Air leak test amongst many other parts with no fix.

My local Indy have advised to go back to basics and concentrate on the plugs as this was when the problems stared. They are looking to try a single prong NGK plug that some other 335i owners are using with success after miss fires on oem plugs. I believe they are from a 2008 mini cooper s and run cooler than oem plugs.

Here is a link to another thread that discuss them:

http://n54tech.com/forums/showthread.php?t=8470

Any experience or thoughts would be great.

Originally Posted by ian2002525

don't you think you also need to change coils??

...

[bryce]

Originally Posted by 335i E92

Thanks, read the whole 9 pages!!

Seems he's using them without issue but it didn't solve his high boost misfire which is not same as my issue.

Anyone else have an opp on this?

although the issues are different, the ngk plugs did greatly reduce the misfires. if you're not having any luck with the oem or bosch plugs, may be worth giving the ngk plugs a try.

[jpsimon]

I tried the NGK plugs and had more timing dropouts than with stock ones - i took them out and went back to stock

[enrita]

You wont cure poor idle by changing to a different type of plug. The issue is somewhere else if it persists on new oem plugs.

[335i E92]

In the last 18 months since the original plugs were changed I've had 3 more new sets of plugs. Each set was in for 6 months and as time went by the idle got fractionally better but still violent.

However every 6 months straight after the new plugs went in the idle missfires went back to being extreme. I've tried very adaptation known to the n54 and not one helped.

It's as though the dme got used to the same plugs for 45k and just can't adapt to the new ones.

What happens when you get timing issues, is this a big problem? I really want to fix this issue but obviously don't want to open the door to a bigger one!!

[335i E92]

Ive spent the last 18 months reading coutless threads and there seems to be a common problem of a rough idle after changing from original plugs. Some have found fixes with adaptiaions others are just living with it and some dont get it at all.

It's a definate problem that some of our ecu's struggle to adapt to the change in plug gaps from old eroded plugs to brand new plugs.

Got an ETS intercooler and AR DP's due to be delivered next week. As with most of you my car is my hobby and passion and I'm desperate to find a solution after 18 months of this BS. Until this is sorted the bolt ons will stay in the box.

Surly its worth a try with the NGK or are we saying I'm playing with fire and will do more harm?

[335i E92]

Originally Posted by enrita

You wont cure poor idle by changing to a different type of plug. The issue is somewhere else if it persists on new oem plugs.

For me it's kinda last chance saloon so worth a go as I'm hitting a brick wall. I can see in the below thread that you're running NGK plugs?

http://www.e90post.com/forums/showthread.php?t=391007

Have they caused you any issues with knock / timing? Are they the ones from a mini coopers s 2008?

[R1000K3]

Originally Posted by 335i E92

In the last 18 months since the original plugs were changed I've had 3 more new sets of plugs. Each set was in for 6 months and as time went by the idle got fractionally better but still violent.

However every 6 months straight after the new plugs went in the idle missfires went back to being extreme. I've tried very adaptation known to the n54 and not one helped.

It's as though the dme got used to the same plugs for 45k and just can't adapt to the new ones.

What happens when you get timing issues, is this a big problem? I really want to fix this issue but obviously don't want to open the door to a bigger one!!

In case you need to replace plugs this often and it has a positive result (and the car is not driven very long) there is for sure another issue.

How does the outgoing plugs look? Are they normal tan-colored, white, sooty black, burnt oil black, shows excessive gap-wear, very eroded?

Depending on the answer it may be possible to trace the underlying cause.

What is the mileage of the engine?

Is it tuned and with what in such case?

My car has 40000 miles and no issues whatsoever on idle or up in rpm independent of the engine is cold or fully warmed up. It has recently undergone a 2-step BG treatment for removing carbon and soot with the BG 44K and BG ISC products to preserve the smooth running. I have never used anything but stock plugs and replace them about every 15000 miles.

[335i E92]

Originally Posted by R1000K3

In case you need to replace plugs this often and it has a positive result (and the car is not driven very long) there is for sure another issue.

How does the outgoing plugs look? Are they normal tan-colored, white, sooty black, burnt oil black, shows excessive gap-wear, very eroded?

Depending on the answer it may be possible to trace the underlying cause.

What is the mileage of the engine?

Is it tuned and with what in such case?

My car has 40000 miles and no issues whatsoever on idle or up in rpm independent of the engine is cold or fully warmed up. It has recently undergone a 2-step BG treatment for removing carbon and soot with the BG 44K and BG ISC products to preserve the smooth running. I have never used anything but stock plugs and replace them about every 15000 miles.

I have recently had a full head off chemical clean, decarb & rebuild with new seals the lot!! This didn't solve the idle. It was trouble free for 45k until I changed the original plugs, it's now 70k. The 3 sets of plugs that have been swapped out since have looked fine, apart from one plug recently on cylinder 6 that was carbed up, this was a leaky injector though that was replaced, again the idle was still rough. I havnt needed to change plugs, I've just done so along the way to try to fix the issue.

Everything that could effect the idle has been replaced or tested and everytime its pointing back to the plugs. Gonna try the NGK plugs next week and then possibly look at a new DME as a last resort.

Has anyone any hard proof that NGK plugs are gonna butt f@&k my car?

Would appreciate any assistance I can get, drivin me crazy = major understatement!!

[R1000K3]

There is no reason at all to believe a 4th swap of plugs will solve a problem that remains after 3 replacements. And the stock plugs works perfectly OK in all N54 from stock to FBO. If the car runs better after a too early plug replacement it indicates the car runs lean and needs the very last bit of energy from the ignition system, which is not normal.

Leave the car at a shop that is familiar with the N54 and they should be able to solve your problem.

A faulty ECU is very low on the list for causes to rough idle.

[335i E92]

Originally Posted by R1000K3

There is no reason at all to believe a 4th swap of plugs will solve a problem that remains after 3 replacements. And the stock plugs works perfectly OK in all N54 from stock to FBO. If the car runs better after a too early plug replacement it indicates the car runs lean and needs the very last bit of energy from the ignition system, which is not normal.

Leave the car at a shop that is familiar with the N54 and they should be able to solve your problem.

A faulty ECU is very low on the list for causes to rough idle.

I have a 1st class local BMW Indy that are scratching thier heads now as what to do. As I said eaier everything has been swapped out, coils, injectors, LPF sensor, complete decarb, techron flushes, air leak test, countless adaptation resets.

It started when I changed the original plugs and has instantly got worse each time I've put fresh ones in over last 3 changes. I know that most seem to swap plugs with no problem but if you search rough idle after plug change you will see there is a community of us with this issue.

I agree DME is a let resort but we are at last resort stages here

[R1000K3]

You don't happen to still have the plug set that did not caused rough idle? Even though it is very unlikely that the newer sets are all faulty this could provide you with the answer.

I've seen people have thoughts the DME needs to adapt so new plugs, which is incorrect. The DME adapts to the engine as a complete unit, where the plugs plays a minor part in this respect. Basically, a plug will ignite the combustion or not, there is not a lot of variations in between during the service life of the plug.

[335i E92]

Originally Posted by R1000K3

You don't happen to still have the plug set that did not caused rough idle? Even though it is very unlikely that the newer sets are all faulty this could provide you with the answer.

I've seen people have thoughts the DME needs to adapt so new plugs, which is incorrect. The DME adapts to the engine as a complete unit, where the plugs plays a minor part in this respect. Basically, a plug will ignite the combustion or not, there is not a lot of variations in between during the service life of the plug.

Unfortunately don't have the origional plugs... There are many in my position, check out mr5's rough idle fix thread.

http://www.e90post.com/forums/showthread.php?t=571344

Many others that have changed original plugs have developed the same rough idle as me, some have and fixed it with the resets via a BT cable in mr5's thread. So adaptation definatley play a part for some of us. Or like me the reset doesn't work and the problem persist.