[najin23]

I had put in new bosch plugs and ran for the past 500 miles. Ride got smoother esp on high boost but still had those intermittent misfires when I idle it for the lights and right after I floor the pedal.

Yesterday, I decided to put in ~0.022" gapped NGK plugs. When I took out those relatively new bosch plugs, I was surprised to see dark carbon on the plugs cylinder 2 again. Basically, that misfire was happening in the same cylinder even with new plugs. Suspected bad coil.

Now, the NGK.....I was amazed by the feel of the car during this morning's commute. NO MISFIRES! Period. Even when I WOT'd (very short period though not to scare other drivers), car just felt so much better.....no engine vibrations.

My car is 6 years old, and I've had JB4 for the past 20K miles out of 45K on the clock now. As soon as I added meth and raised my psi to ~17nish, the vibration started. It went away 70-80% after new bosch but not completely. NGK (gapped to 0.022") was put in and it's gone. Amazing! I've had those intermittent and almost stalling misfires ever since I got this car, and they are gone now. Now, I am pretty sure higher voltage upgraded coils should help also, but they are very expensive.

Next thing, I am going to check and see any black carbon present on the NGK plug cyl 2. If there is, then the coil will be swapped to cyl 6. If I see any of that black carbon on plug 6, then the coil will be replaced.

Now, this doesn't have to be the NGK brand. This 5992 plug was easy to adjust the gap with a coin looking gap gauge. So I would say gapping closer than the factory setting on any brand should help with any highly reving engine.

I will further post pictures of plugs and possibly some logs.....but I don't know what to look at.....maybe the timing values? My timing shoots up to 20 as WOT starts but stay at 15 a while then quickly goes to 0 as boost falls. Is it normal? What's the unit on the values?

[08n54]

On turbo cars I usually gap plugs between .019"-.025". Depends on how much hp the car is putting out. N/A cars can run like .045", I remember on my integra i had a lot of miss firing but I gapped it down to .019" and it went away. I don't know what BMW is gapped from stock.

[rudypoochris]

Yeah, sounds like you have other issues if you're misfiring WOT at 17psi on new OE plugs. That being said I run these plugs and they are great.

[najin23]

Originally Posted by rudypoochris

Yeah, sounds like you have other issues if you're misfiring WOT at 17psi on new OE plugs. That being said I run these plugs and they are great.

And I think my problem is solved with these closer gapped plugs. I really doubt that it's from any other issues, valves or injectors...I don't want to see that route to be honest. Apparently though, closer gapped plugs fixed the problem(further evaluate to find out if it's from coils) for now.

[najin23]

Originally Posted by 08n54

On turbo cars I usually gap plugs between .019"-.025". Depends on how much hp the car is putting out. N/A cars can run like .045", I remember on my integra i had a lot of miss firing but I gapped it down to .019" and it went away. I don't know what BMW is gapped from stock.

was integra a turbo car? Didn't know.

I can tell my bosch plugs were gapped closed to 0.03" or higher just by looking.

[rudypoochris]

I think .7mm is stock. That's around .028".

[Eleventeen]

It sounds like an injector issue on cylinder 2, especially with the black plug.

[08n54]

Originally Posted by najin23

was integra a turbo car? Didn't know.

I can tell my bosch plugs were gapped closed to 0.03" or higher just by looking.

Acura Integra, I turbo'd it years ago.

[najin23]

Originally Posted by Eleventeen

It sounds like an injector issue on cylinder 2, especially with the black plug.

I think you are right.
Here are pictures from cyl 1-6 after 500miles. cyl 2 and 5 plugs have two pictures each.
#1


#2



#3


#4


#5



#6

[najin23]

Should I find a way to get new injectors?
I don't know. My instinct says run another 500miles on the new NGK and evaluate; compare to the bosch plugs. If I see the same results as those pictures above, I may really have to either swap the injectors(esp for 2 and 5) or eventually get new ones. What about cleaning injectors? Does any shop do that? I am sure dealers would do but they might just push me to replace with new ones or charge me for a diagnostic fee. As I test out the NGK plugs, I may probably start looking into getting new injectors.
Thanks for the insight.

[Terry @ BMS]

Interesting but good news. I may consider stocking these plugs for you guys. NGK wanted us to order a minimum 15,000 of them (lol), but have a note out to our local distributor to see if we can work something out.

[najin23]

Terry.
I was really going to pm you for stocking these along with those cheap coin looking gauge tools. I just can't find a way to describe it, but my 6 yo bmw became like a new engine. From engine tone to almost zero vibration were something that I could tell the difference just like when I got jb4 installed for the first time. Now I drove 25k miles w/n a year period 2012, and I know I can tell the difference. I do have logs from the bosch above. So once I get logs for the NGK, I will post both.

[najin23]

Just pasting this for those of you have some misfire issues.

CORRECTION
In case of a reproducible "cold start" rough engine running with corresponding misfire faults, replace the high
pressure injector of the affected cylinder, using the improved part (P/N 13 53 7 585 261). Follow TIS Repair
Instruction RA 13 53 310 for injector removal and installation. If the spark plug from the misfiring cylinder shows
wetness (fuel soaking) after cold start removal, then it should be replaced as well.

I will try this to see if I get any soaked plugs.

[rudypoochris]

Originally Posted by Terry @ BMS

Interesting but good news. I may consider stocking these plugs for you guys. NGK wanted us to order a minimum 15,000 of them (lol), but have a note out to our local distributor to see if we can work something out.

What would be really sweet is if they gapped them for us at 0.022". I would pay $1-2 a plug more for that and I actually have the tools.

[Carl Morris]

I'd rather just gap them myself, I don't trust pre-gapped enough to install without checking.

[najin23]

Originally Posted by Carl Morris

I'd rather just gap them myself, I don't trust pre-gapped enough to install without checking.

+1 since I have the gauge now....

[bimmer305]

I also had a misfiring issue on cylinder 3 every time I went WOT. At first I though it was a bad codded injector because I just had 6 new injector, coils and spark plugs put in.

I swapped coils and spark plugs and misfire staid on cylinder 3.

I ended up replacing the injector and misfire was gone.

Fault injector had lots of carbon buildup, but spark plug was clean

If you can take out the injector and inspect it maybe?

On a side note, thanks to Terry for helping me troubleshooting it. He found my low fuel pressure sensor was defective, I didn't know.

[najin23]

Wow.....that does really look bad. I am going to swap coils then injectors.I had significantly reduced small misfires by gapping the ngk plugs. So far superb results. I'd love to take out and physically examine injectors. Now when I take em out can I just put em back? Thanks.

[bimmer305]

Originally Posted by najin23

Wow.....that does really look bad. I am going to swap coils then injectors.I had significantly reduced small misfires by gapping the ngk plugs. So far superb results. I'd love to take out and physically examine injectors. Now when I take em out can I just put em back? Thanks.

Yes. I took mine off a couple of times and put it back in, and no issues.

[rem3]

What is the NGK ref?

[az335iat]

Originally Posted by Terry @ BMS

NGK wanted us to order a minimum 15,000 of them (lol),.

Come on Terry.... place the order for 15k!!!!!

At 6 plugs/engine and perhaps 200 orders/year it would only take you........... 12.5 years to sell all of them.

[az335iat]

Originally Posted by rudypoochris

What would be really sweet is if they gapped them for us at 0.022". I would pay $1-2 a plug more for that and I actually have the tools.

I wish we were neighbors...... $4/min is good pay.

Gapping a set of plugs has to be the easiest part of replacing a set.

[az335iat]

Originally Posted by rem3

What is the NGK ref?

NGK premium platinum single electrode spark plugs to replace the Bosch OEM plugs.

http://www.n54tech.com/forums/showthread.php?t=17698

[najin23]

Originally Posted by az335iat

I wish we were neighbors...... $4/min is good pay.

Gapping a set of plugs has to be the easiest part of replacing a set.

+1

[cb224]

Originally Posted by najin23

I had put in new bosch plugs and ran for the past 500 miles. Ride got smoother esp on high boost but still had those intermittent misfires when I idle it for the lights and right after I floor the pedal.

Yesterday, I decided to put in ~0.022" gapped NGK plugs. When I took out those relatively new bosch plugs, I was surprised to see dark carbon on the plugs cylinder 2 again. Basically, that misfire was happening in the same cylinder even with new plugs. Suspected bad coil.

Now, the NGK.....I was amazed by the feel of the car during this morning's commute. NO MISFIRES! Period. Even when I WOT'd (very short period though not to scare other drivers), car just felt so much better.....no engine vibrations.

My car is 6 years old, and I've had JB4 for the past 20K miles out of 45K on the clock now. As soon as I added meth and raised my psi to ~17nish, the vibration started. It went away 70-80% after new bosch but not completely. NGK (gapped to 0.022") was put in and it's gone. Amazing! I've had those intermittent and almost stalling misfires ever since I got this car, and they are gone now. Now, I am pretty sure higher voltage upgraded coils should help also, but they are very expensive.

Next thing, I am going to check and see any black carbon present on the NGK plug cyl 2. If there is, then the coil will be swapped to cyl 6. If I see any of that black carbon on plug 6, then the coil will be replaced.

Now, this doesn't have to be the NGK brand. This 5992 plug was easy to adjust the gap with a coin looking gap gauge. So I would say gapping closer than the factory setting on any brand should help with any highly reving engine.

I will further post pictures of plugs and possibly some logs.....but I don't know what to look at.....maybe the timing values? My timing shoots up to 20 as WOT starts but stay at 15 a while then quickly goes to 0 as boost falls. Is it normal? What's the unit on the values?

What torque specs did you use?