Why Is It Misfiring

[Thamobster15781]

hey i had a problem with my eclipse misfiring above 4 grand in second through fifth gear..i recently changed my plugs and figured they were gapped wrong..so i just bought iridium ngk plugs and gapped them to what i was told at autozone and installed them..me and my girl took it out for a spin and it was great...no misfiring...but later that night we went out with two friends and it started misfiring again..when they got out though it didnt...will the extra weight cause this or is my gap still just off...does anyone know a good gap for these plugs on a non-turbo to turbo conversion...or wont it matter that its now turbo....thanks nick

 

[DSMSpyder99]

well here are a couple suggestions you have the upgraded plugs but do you have
•upgraded spark plugs wires like Magnecore 8.5mm
• are you using at least 91 octane gas

 

[Thamobster15781]

no i havent upgraded the wires but ive never had a wire problem or plug problem til now....it seems to be doing it in 3 4 and 5 gear only...and yes i use 93 octane so im not sure what it could be

 

[Tyler_Baker]

Originally posted by Thamobster15781
no i havent upgraded the wires but ive never had a wire problem or plug problem til now....it seems to be doing it in 3 4 and 5 gear only...and yes i use 93 octane so im not sure what it could be

High RPM misfire is related to ignition, I am 99% sure that it is your plug wires. Same thing happened to me, I picked up some lifetime warranty wires (Autolite) from Schucks where I work and never had the problem again. Since they have a lifetime warranty, ever time I change my plugs, I warranty the wires out and get a new set! Hope that helps!

Edit: They arc to the cylinder head really easily when they are worn down.

 

[Thamobster15781]

ok i just checked out my wires and they seem to be ok...although i upgraded my plugs i used a cheap set before that were also acting up..would it actually have something to do with the wires though...why would the wires need to be upgraded and why would mine be bad

 

[Tyler_Baker]

Originally posted by Thamobster15781
ok i just checked out my wires and they seem to be ok...although i upgraded my plugs i used a cheap set before that were also acting up..would it actually have something to do with the wires though...why would the wires need to be upgraded and why would mine be bad

You can't tell the wires condition for the most part by just looking at them. If the insulator is worn down at all, that powerful spark will arc to the cylinder head causing a cylinder to miss. At higher RPM's the spark is stronger so it is easier for it to miss. Are your wires the ones that came in your car stock. I would bet that they are factory and you really should get new ones anyway. My JDM engine with 30K miles on it, came with factory wires and started missing 3 weeks after I had the motor in my car. Lates

 

[Enigma_Man]

I'm not sure about the Iridium plugs, but a lot of turbo guys have had very similar problems using "fancy" spark plugs.

You, having an added turbo, would probably see the same problems.

You can find the exact designation of plug to use repeated numerous times around this site, I don't have it offhand.

Personally, I also use NGK wires, and have had nothing but good luck for two years with 'em.

-Jesse

 

[tsi20gawd]

run either bpr6es ngks or bpr7es if your running high boost,
nkg wires are VERY good.
if you look at you wires on the plastic extention that goes into the spark plug tube of the head there will be a white dust where they are arcing

 

[Tyler_Baker]

Originally posted by tsi20gawd
run either bpr6es ngks or bpr7es if your running high boost,
nkg wires are VERY good.
if you look at you wires on the plastic extention that goes into the spark plug tube of the head there will be a white dust where they are arcing

Listen to this guy. He knows his shit ^ Sup Bryan.

 

[tsi20gawd]

dude you start sayin' stuff like that people will think i have a fast DSM or sumthin'
I CANNOT wait for that kick ass computer!!!