Ignition Breakup

[Badgaz]

I have an intermittent problem.....occasionally when i launch 1st gear and hit the limiter then dump and go WOT in 2nd gear i get what feels like a missfire...but by the middle of third gear it goes i keep my foot up it. I'm wondering if this could be a fuel problem instead of ignition? i don't get knock when this is happening but i've not had a wideband on when its done it. i'm up to the last simple thing to try and correct it which is reduce spark plug gap to 0.6mm thought i might try changing the coil pack loom and check the ignitor...any thoughts?

[sonicz]

My thoughts are don't go to 0.6mm and you should try brand new coils and new ignitor before doing anything else. The factory gap is 1.1mm and 0.8mm most of the time is enough if you have weakening coils to avoid spark blowout, but running 0.6mm is just crazy imo. You will be loosing power. What heat range plugs you running? Better not go 7 unless you have a race engine.

Edited March 9, 2014 by sonicz

[Badgaz]

I have split fires, and NGK bkr7eix new plugs gapped at 0.8mm, i've also set my dwell time to that of a factory GTR. I haven't done the ignitor yet and i was reading around that re-doing the earths for the coil loom is a good thing to do. I'm pushing 16psi through a factory highflowed turbo. jeez hope its not one my coils...they're fekin expensive.

[Got a Pulsar]

16psi on what ECU? Stock?

If so, that's the problem.

[sonicz]

Yup 16 Psi will definitely hit the "boost cut" of the stock AFM, but I doubt thats his problem as he is able to go WOT in 1st and the problem only arises at the start of 2nd.

Man why are u running Iridium plugs with a 7 heat range gapped at 0.8mm? Thats just drowning the motor each way possible.

Iridiums suck, and 7 is too cold unless the engine is a heavily tuned race engine which spends most of its liviving at 8000RPM on a racetrack and the stock gap is 1.1mm.

Get coppers. Go to 6 heat range. You can stick with 0.8mm to prevent blowout, but you may find you are ok with 1.1 as well. You will get much more, power, economy, efficiency at all RPM. Just watch for pinging and not leaning out the engine when you make the change. I can actually say I speak from 1st hand experience and trial and error on this. Thank me later?

Edited March 9, 2014 by sonicz

[Badgaz]

i also have a z32 afm and powerfc. the plugs i had in before these ones were pfr6g gapped to 0.8mm. its cheap enough to try the bcp's i suppose. the problem started on the pfr6g's which is one reason why i went the heat range colder.

[sonicz]

Yup try the coppers and report back. If your gapping the plugs yourself go for a bit higher to like 0.9mm, or 1.0mm

[hypergear]

might worth a while checking all the connection with the wiring loom, I had this issue on my CA before, and turned out to be a broken connector. unless its the fuel pump cutting out intermediately which can also lead to similar effect.

[Badgaz]

thanks good advice. I have had a sneaking feeling about the pump and the coil loom is brittle as Hell...to the point where some of the plastic clips have broken. as far as fuel pumps go...what is the recommendation these days? aem, walbro or deutschwerks

[KiwiRS4T]

I am running PFR7G gapped to 0.8mm at the recommendation of my tuner and it revs to its 7000 maximum at 1.5 bar no problem. The fact that your engine runs fine in 1st and not in 2nd suggests you may be running out of fuel. The new Walbro 465LPH E85 pumps are supposed to be pretty good (best if directly wired for full battery voltage).

[hypergear]

I found only bosch pumps cutting out intermediately, especially the 040. It makes a loud buzzing sound also. Walbro pumps usually just blows up straight, I have not experienced intermediate cuts with them. The 460L/H Walbro if are you getting/got one. it needs an extra earth, which you just tee the earth wiring out side the tank, and bolt it to the chassis.

Plugs needs to be gaped to 0.8 as others mentioned.