gm s/c gap, misfires at idle - Boost Forum

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gm s/c gap, misfires at idle
Monday, November 27, 2006 12:56 AM
for some reason im getting a CEL here and there about once a week or so about misfire on cylinder 3 & 4 on start up, now ive never gotten them both together but ive cleared one and the other came on shortly after. My plugs are ngk irraniums gapped at .040 and im noticing the car doesnt start as easily as it used to so i even give it alittle gas once and a while so it starts up smoother. So what do you guys think i should gap the plugs at? im thinking .035 because if its misfiring at .040 then you wanna go closer i think. thanks again.





Re: gm s/c gap, misfires at idle
Monday, November 27, 2006 3:13 AM
that's odd...

well I might not have the same spark plugs as you but I do have the 2 Stage Colder AC Delco Spark Plugs (.035 gap)

That's my current setting, seems to work just fine. don't have misfire issues. been pretty high up there in the revs also so I don't know what to tell you for your misfires. give the lower gap a try.



Re: gm s/c gap, misfires at idle
Monday, November 27, 2006 6:32 AM
are those plugs tr6 or tr7... you might have some issues with starting if they are tr7... tighter gap usually makes cold start more difficult too... but you could try down to 25-28 thou..


HP Tuners | Garrett T3/T04B | 2.5" Charge Pipes | 2.5" Downpipe | 650 Injectors | HO Manifold | Addco front/rear | Motor Mounts | HKS SSQV | Spec stage 3 | AEM UEGO Wideband | Team Green LSD | FMIC | 2.3 cams | 2.3 oil pump swap | 280WHP | Now ECOTECED

Re: gm s/c gap, misfires at idle
Monday, November 27, 2006 7:46 AM
im using the tr5's, i just regapped them at .035 and now the idles rough as well and it trys to stumble kinda after shutting it off and turning it back on with like a 5 minute break inbetween. i have a stock afpr also if anyone was wondering. any tips guys?




Re: gm s/c gap, misfires at idle
Monday, November 27, 2006 9:12 AM
ive got tr6's and .035 gap , never had any issues

how do those plugs look compaired to the other 2 plugs ?

also check and clean the idi cover inside and out , and make sure the springs are ok

and check the injectors , they might need to be cleaned







Re: gm s/c gap, misfires at idle
Monday, November 27, 2006 9:18 AM
the other plugs looked the same, so should i get some injector cleaner you think?




Re: gm s/c gap, misfires at idle
Monday, November 27, 2006 10:01 AM
IMO injector cleaner isn't needed when you're burning premium fuel, it has more detergents and whatnot compared to regular gas so it precludes the need for injector cleaning.



14.330 @ 96.37mph
Re: gm s/c gap, misfires at idle
Monday, November 27, 2006 12:15 PM
just cause it has more doesnt mean they dont need to get cleaned

like i said clean all the ign stuff and inspect it

also try putting the #3 and 4 plugs in cyl 1 and 2 , and see what happens







Re: gm s/c gap, misfires at idle
Monday, November 27, 2006 5:57 PM
From: Kristopher Zdral [mailto:KZdral@ngksparkplugs.com] On Behalf Of Info
Sent: Thursday, November 09, 2006 2:02 PM
To: Festa, Bryan
Subject: RE: NGK Form Mail

Hello,

The correct plug for this vehicle one stage cooler in Iridium IX is the
LTR6IX-11 stock no. 6509. You may also want to consider reducing the gap from .044" to .035" to reduce spark blow out due to combustion chamber turbulence. Note: these are fine wire plugs and special care is required when adjusting the gap. Do not use anything that will pry against the center firing electrode as plug damage could result. TR6 and TR7IX are incorrect thread designs for this engine and should not be used.

Kristopher Zdral
Technical Support Representative
NGK Spark Plugs (U.S.A.), INC.

I followed this to the T and my car runs better than ever!!!



Re: gm s/c gap, misfires at idle
Monday, November 27, 2006 6:01 PM
The ECOnator (Encriptor) - thats for an ecotec. He's got an LD9. Boosted I run TR6IX gapped at 0.035" and haven't had a problem.



Re: gm s/c gap, misfires at idle
Monday, November 27, 2006 6:56 PM
Gotcha, I didn't see what motor he said he had. But I'm sure if he e-mailed NGK like I did they would give him a good answer. They helped me out greatly.






Re: gm s/c gap, misfires at idle
Thursday, November 30, 2006 7:30 AM
i had a simular problem,my engine is an ECOTEC though,turned out to be the spark plug boots,,hope this helps


if at first you don't succeed,you should probably give up
Re: gm s/c gap, misfires at idle
Thursday, November 30, 2006 1:53 PM
I have the 2000 LD9 with GM S/C and a NX kit.

After talking with
Kristopher Zdral
Technical Support Representative
NGK Spark Plugs (U.S.A.), INC.
at 1-877-473-6767 prompt #2 for assistance

I am running NGK TR6IX P/N3689 which I bought at the local advanced auto. As per NGK recommendation I gapped them at .035. Running good to date.

Additionally; I have the Nitrous Express NXL kit
Kris recommended going 2 steps colder if I boost and use larger nitrous shots. NGK TR7IX P/N3690 gapped to .035, which I also bought at advanced auto. Have not installed yet because I started a motor rebuild for winter.

Hope this helps,

Don



Re: gm s/c gap, misfires at idle
Thursday, November 30, 2006 2:07 PM
I had very simular issues on my 2000.

NGK says the TR5IX are for the stock N/A and may have trouble with the S/C boost, so I returned mine before install.

With the TR6IX's I also replaced the before CAT O2 sensor just to be safe (Bosch P/N 13191 $50 at autozone)

Cleaned up all the problems. The O2 sensor surprised me by being very clogged.

Notes:
1. I had a NGK (NTK) O2 sensor but a new one would take to long to get in the mail. Did not want to wait.
2. Advanced auto wanted $90 for the same Bosch O2 sensor.

Hope it helps



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