Missfiring / not all pistons running after replacing sparks and cleaning coil pack

[ozalkl]

hi guys, recently managed to get my car started and off the limp mode, what i did was basically clean the coil pack and the sockets with electrical contact cleaner, i also replaced my sparks with the one recommended which was NGK V-Power Racing (R5671A-7).

after i put everything back in place and start the engine, it started but with shaky feeling, more like one piston is off or no fire, i would like to know how to troubleshoot to see which piston is not firing and how to know which of the coil pack is having the problem.

I also read around that some sparks need to have spacing? do i need to do this with the sparks i got, since im just running bone stock gtst type m

[keith]

when its running just unplug each coil, one at a time, if i makes a difference that coil is firing, if not, then u have a problem with fuel or spark there, take the coil out, put a plug in it and ground the tip of the plug to see if theres spark, as for gaping the plug, i dont know about those ones, i buy bkr7e's and just drop them in, they work fine

[evilgtr]

Did you check the gap on each plug before you installed them ?

[gtrjon]

Did you check the gap on each plug before you installed them ?

yea you should of re gapped them to .08 i believe

[beacher1B0]

NGK V-Power Racing (R5671A-7)

The -7 would mean gapped to .07, Correct?

[DarkCaporaL]

That's the heat range.

[ozalkl]

so shall i gab them? or get different sparks? please advice, im running stock rb20gtst automatic..

[DarkCaporaL]

The plug gap usually becomes an issue at higher RPMs. If it's missfiring on idle it's likely something else. Still it doesn't hurt to check the plugs and regap them, it's not hard or long at all to do.

I would troubleshoot as keith posted earlier (2nd post) to find out exactly which cylinder is missfiring. Start the engine, then unplug and replug each coil one at a time, if you see a difference then that coil is firing, move on to the next one.

If you unplug the coil and it seems like nothing is happening, you have found which cylinder is not firing. To isolate if it's indeed the coil, switch the coil in this cylinder with another cylinder and see if the problem follows it, i.e. the cylinder in which you moved this coil will be missfiring now, instead of the original cylinder that was missfiring.

[ozalkl]

will do the test this weekend, i drove her to the garage and so far everything is working in order except from the low rpm missfiring

[Skym]

Another way is to pull the sparkplugs and check the tips. The tip of sparkplug on the cylinder that is not firing should be black. Also grey tracking marks on both sides of coilpack, just under mounting bracket (splits along the seam that joins 2x parts of coilpack and arcs against mounting bracket) is another sign coilpack is leaking. Usually 2x coilpacks fail and the rest are ok. On my car it was 4th and 5th cylinder, looking from front to back of engine.

Can dip them in resin or similar to reseal the crack. Or some use I think was high temp silicon?

Another way is using plastic washers, so coilpack mounting bracket doesn't make metal to metal contact with head. But I wouldn't do it that way, as could melt washers when head gets hot enough, unless it's high temp plastic.

[ozalkl]

cool, i will open and check the sparks and trace my work from there.

[ozalkl]

problem solved, it seem it was a faulty injector socket, replaced it and it worked

thank you guys for the help and input