Yet Another Missfire Problem

[leeboi33]

hey guys about 10 months ago i replaced my coilpacks with splitfires and it fixed my missfire but this morning i went for a drive and its back on both normal boost and 10 psi. does this mean my coil packs are fried again??? do splitfires come with a warranty?

[Sheriff Wan]

Dont think you could ruin them that quickly.

Did you change your plugs when you changed coils?

If so what plugs did you put in? & What were they gapped to?

[PM-R33]

BCPR7E every 5000km and you will never have miss fire problems.

[leeboi33]

yeah i changed the plugs before i changed the coil packs with iridium ones wich was around 4000 k's ago cost me a fortune , but just then i went for a drive and the outside temp is alot warmer now, and funny enough no missfire im so confused........... did i mention my car was for sale????????? lol

Edited February 18, 2009 by leeboi33

[Sheriff Wan]

leeboi33

What type of plugs did you use? Just saying they cost a fortune and they are iridium isnt telling us anything other than you wasted your money...

What was the part number and what were they gapped to?

My suggestion is to get some NGK BCPR6E or BCPR7E plugs and try them - they are about $3 a plug so for $18 to fix your problem I think this is a cheap way to start...

[leeboi33]

gees what a pain in the ass having to take off all that stuff just to check the numbers. but im fairly sure i just went what was in the book for ngk iridium. but even so does the spark plugs make a difference? i mean i changed them and it missfired then changed my coilpacks and it went away, surely that means its the packs not the plugs

Edited February 18, 2009 by leeboi33

[Sheriff Wan]

Holly hell...

Yes it will make a difference... Gee what a pain in the ass asking you the same question again and again.

If your looking for more guesses and want to keep running round in circles thats fine. If your looking for help - maybe start looking to eliminate problems by actually doing something instead of just typing...?

Spark plugs have many different types of heat ranges and gaps which will all effect how the engine runs. Normally a gap of 0.8mm will be fine, however, iridiums can come with a gap of 1.1mm this will make a difference as there is a bigger gap sometimes the spark gets blown out and cant ignite the mixture = hence a missfire.

Not having a go, but it does wear a little thin you just coming back and telling us it ran ok for 5 seconds and it was hot and not giving any detail.

[__PhaseShiftDown]

He said he's running normal boost of 10 PSI, so there is really no need to gap the plug to .8. Only when you are running higher boost and getting misfire, then you should gap it smaller. My 32GTR is running stock boost and stock coilpack and runs 1.1mm gap no problem.

You should always run the biggest gap possible since that will provide you with a stronger spark and hence cleaner burn. It is possible it is caused by coil pack. Do you tighten down the plugs to the correct torque?

[PM-R33]

If he is running iridiums, then it is a 1.1mm plug, as the NGK books for skylines all list iridium/platinum plugs at 1.1mm. Hence why at my work i have crossed this crap out and put down BCPR7E since i get this problem with customers on a weekly basis. Get BCPR7E plugs and your missfire will go away.

Done and done.

Edited February 18, 2009 by PM-R33

[leeboi33]

hey i did abit of reasearch and found this on youtube

its the exact same problem as mine and he fixed it with new plugs so maybe after 4000 or so k's the plugs do need changing wich sucks cos i payed so much for them , i have heard of iridiums not lasting very long but it seems like it was true so next week i will change the plugs back 2 copper ones and let u all know what happens