[KaiserN54]

I am running the Vishnu Flex fuel setup, which runs 19-20 lbs of boost at times. Because of the high boost, I run NGK 5992 gapped to .21. However, i still get faint misfires under full boost in 5th, 6th gear, with codes to match for each cylinder. If stay out of high boost (over 16-17) i don't have problems. I am thinking about going to a 0.18 or a 0.17. Is this too small? All coils were replaced about 9 months ago.

[KaiserN54]

Anyone?

[AK 335i]

Originally Posted by KaiserN54

I am running the Vishnu Flex fuel setup, which runs 19-20 lbs of boost at times. Because of the high boost, I run NGK 5992 gapped to .21. However, i still get faint misfires under full boost in 5th, 6th gear, with codes to match for each cylinder. If stay out of high boost (over 16-17) i don't have problems. I am thinking about going to a 0.18 or a 0.17. Is this too small? All coils were replaced about 9 months ago.

what cylinder are you missing in>?

and i hope u mean .022?

[SteveAZ]

I run at .02 and have been for about 8k or so on 100% E85 (usually tested at E80-E82.5) and I also peak at about 19psi. I don't have any issues with that. E85 is susceptible to pre-ignition, so it doesn't take much of a spark to ignite it (think glowing spark plug electrode) as opposed to gasoline that is more pre-ignition resistant (takes more of a spark) but more susceptible to detonation.

I'd want to see logs to see AFRs and such.

[KaiserN54]

Originally Posted by AK 335i

what cylinder are you missing in>?

and i hope u mean .022?

Sorry, I do mean .022.

I am missing in all six cylinders plus I am getting a 2e77 (voltage supply). I have read this code can be related to NLS, but I only have the NLS wired, not activated. plus this is happening during acceleration, not shifting.

Again, I can WOT 1-4 with no misfires whatsoever. Its only 5-6 that it happens, especially from lower RPM's, like 3k.

The coils are all new and I just put these plugs in last week. Here are the codes:

U0D97 (no one has ever figured that one out, including the dealer)
P2DED (had popped up with or without the procede, I think it may be my vishnu lpfp booster)
P2E77
P2E1D
p2E18
p2E1C
P2E1A
P2E19

[KaiserN54]

Originally Posted by SteveAZ

I run at .02 and have been for about 8k or so on 100% E85 (usually tested at E80-E82.5) and I also peak at about 19psi. I don't have any issues with that. E85 is susceptible to pre-ignition, so it doesn't take much of a spark to ignite it (think glowing spark plug electrode) as opposed to gasoline that is more pre-ignition resistant (takes more of a spark) but more susceptible to detonation.

I'd want to see logs to see AFRs and such.

I don't have a log with these plugs, but here is a log showing how the car does on 100% E85. You may notice throttle closures, which is why I went back to the procede vs flash only:

http://datazap.me/u/atomos319/wedge-...data=1-6-7-8-9

[AK 335i]

couldnt tell you..

i ended up running .019 but im on 30psi on a big turbo

[3000GT MR]

I'm running a Keene bell boost a spark with plugs gapped at .025 and 26-27psi of boost. seems to be working great for the past 10k miles.

[AK 335i]

Originally Posted by 3000GT MR

I'm running a Keene bell boost a spark with plugs gapped at .025 and 26-27psi of boost. seems to be working great for the past 10k miles.

Nice. We have talked about running one of these one my car.

[3000GT MR]

Originally Posted by AK 335i

Nice. We have talked about running one of these one my car.

It was a pain at first, just going to 30% I started frying plugs. I want non resistor plugs so bad but that's not going to happen any time soon. If you do decide to hit me up

[parksjm7]

Originally Posted by 3000GT MR

It was a pain at first, just going to 30% I started frying plugs. I want non resistor plugs so bad but that's not going to happen any time soon. If you do decide to hit me up

Hi I've been following your threads and got the ngk 4786s running and want to know what the benefits of a nonresistor spark plugs are.

[3000GT MR]

Originally Posted by parksjm7

Hi I've been following your threads and got the ngk 4786s running and want to know what the benefits of a nonresistor spark plugs are.

Manufactures put resistors in sparkplugs to control EMI. Nowadays engines and cars have so much computer crap in them that they need these resistors so that you dont hear the sound of ticking or a 40's radio trying to tune. Bad thing about the resistor is that it lowers the energy to the tip of the plug. So essentially you have a weaker spark and you can only put so much added power 16-17 volts or so before these resistors start frying. With out them you can add 20+ volts if you really want

[MDORPHN]

I'm currently running .016 but am planning to re-gap to .018 in the Fall since I suspect cold starting will become an issue.

Neil

[Mike@N54Tuning.com]

Originally Posted by MDORPHN

I'm currently running .016 but am planning to re-gap to .018 in the Fall since I suspect cold starting will become an issue.

Neil

Wow thats a small gap

Mike

[parksjm7]

Originally Posted by 3000GT MR

Manufactures put resistors in sparkplugs to control EMI. Nowadays engines and cars have so much computer crap in them that they need these resistors so that you dont hear the sound of ticking or a 40's radio trying to tune. Bad thing about the resistor is that it lowers the energy to the tip of the plug. So essentially you have a weaker spark and you can only put so much added power 16-17 volts or so before these resistors start frying. With out them you can add 20+ volts if you really want

Thanks for the explanation. Yeah I've noticed a slightly increased ignition noise, or maybe it's a placebo effect of reading up on all the info related to resistor spark plugs, gaps, etc.

Could you help me in narrowing down a coldstart misfire?

I've read posts that pointed me to increasing the gap from .022 to .025(which you recommend), and now I'm at .027; I run stock to 12 PSI (procede v5 map 1), so nothing major and from what I hear, the wider gap should be better for a daily driver that is driven for short durations without chances to open up the throttle.

It's only in the morning that the misfires happen and when I get back to my car to start it up for lunch break, no issues. (with all three .022/.025/.027 electrode gaps)

I'm starting to suspect that it's my injectors slightly leaking, filling up the combustion chambers during the night (mine is an 07 build 09/2006, earlier than the first models to be covered by the injector recall, but the injectors are ancient nonetheless) and that it's becoming apparent with the newer spark plugs due to the ignition being stronger than the old plugs.

I've done many WOT runs with it on all three gap settings and each time I pulled the plugs out, they showed no signs of fuel nor carbon fouling.

I'm hoping that my hunch is wrong.

EDIT: I reset the adaptations each time I changed the gap widths as well.

[optigrab]

Originally Posted by 3000GT MR

It was a pain at first, just going to 30% I started frying plugs. I want non resistor plugs so bad but that's not going to happen any time soon. If you do decide to hit me up

You mean 30% on the boost a spark?

• Adjustable from 0-50% (13.5 - 20 volts)

[3000GT MR]

Originally Posted by parksjm7

Thanks for the explanation. Yeah I've noticed a slightly increased ignition noise, or maybe it's a placebo effect of reading up on all the info related to resistor spark plugs, gaps, etc.

Could you help me in narrowing down a coldstart misfire?

I've read posts that pointed me to increasing the gap from .022 to .025(which you recommend), and now I'm at .027; I run stock to 12 PSI (procede v5 map 1), so nothing major and from what I hear, the wider gap should be better for a daily driver that is driven for short durations without chances to open up the throttle.

It's only in the morning that the misfires happen and when I get back to my car to start it up for lunch break, no issues. (with all three .022/.025/.027 electrode gaps)

I'm starting to suspect that it's my injectors slightly leaking, filling up the combustion chambers during the night (mine is an 07 build 09/2006, earlier than the first models to be covered by the injector recall, but the injectors are ancient nonetheless) and that it's becoming apparent with the newer spark plugs due to the ignition being stronger than the old plugs.

I've done many WOT runs with it on all three gap settings and each time I pulled the plugs out, they showed no signs of fuel nor carbon fouling.

I'm hoping that my hunch is wrong.

EDIT: I reset the adaptations each time I changed the gap widths as well.

Id start with coils and injectors.

Originally Posted by optigrab

You mean 30% on the boost a spark?

• Adjustable from 0-50% (13.5 - 20 volts)

Yes. IIRC its around 15.75v. Its been a while, i'm about to revisit it shortly

[optigrab]

Originally Posted by 3000GT MR

Yes. IIRC its around 15.75v. Its been a while, i'm about to revisit it shortly

Cool what coils and plugs are you currently running

[3000GT MR]

Originally Posted by optigrab

Cool what coils and plugs are you currently running

Stock coils and NGK 4786's gapped to 0.022"

[Julian2485]

Originally Posted by 3000GT MR

Stock coils and NGK 4786's gapped to 0.022"

What ngks are those I thought we we're suppose to use the 95770 which are the new ngk 5992 ?

[xuzax]

I know this is so old but this is deff a injector issue. One or more of your injectors were leaking

[whyzee125]

Mine will misfire at .022 as well but she loves .018. I'm on 100% e85, 21psi on stock turbos. No cold starting issues aside from the usual e85 cold start issues in really cold weather. I left the same plugs in and I'm currently on pump gas and it started up just fine at 9 degrees the other day.