Ignition Breakdown (Techie Question)

[Skyrine-Dave]

ok here's my tale

Today on the dyno my car was given a run up with new turbo and new injectors with the old tune.

- 114hp @ wheels

- 10.1 AF.. or lower... 10 was the lowest on the scale

it was a no brainer that it was over fueled.

A quick adjustment of maps:

- 209hp@wheels@6000rpm

Nothing special, car had that in its previous stock form. However the turbo wasnt reaching boost till 4500 rpm, then slowly built up boost to 14psi.

- Finger was pointed at the EMS boost control solenoid being to slow to bring on boost.

The solenoid was sorted and boost was coming on at 3200rpm feeling stronger. BUT.. heres the but...

- Soon as the car reaches 5000rpm it seems like there is an ignition cut and stops the power.

We are scratching our heads as to why, New plugs were put in and gapped to 0.8.

- Rev cut is 7900 hard, 7500 soft

- boost Kpa cut is set at well over 1bar ... car hit 17.1psi at one stage earlier.

- boost when ignition breakdown occured was 12psi

Anyone got any ideas?

*Have been told*

- at higher boost pressure the spark plug electrodes can bounce resulting in ignition breakdown... (the tips close then open.. boucnce)

[N I B]

Are u running waste spark?

[Skyrine-Dave]

i *think* i am

what ever the stock ignition setup is for an Rb20. Cuz i doubt it has been changed by the EMS as it still uses the stock igniter module.

[N I B]

Most Aftermarket ECUs use the factory module but use 3 outputs paired up and this is not the best setup but normally ok on lower powered cars.Try BCP6E NGK plugs at .6mm gap.

[Skyrine-Dave]

Steve,

I am using BCPR6ES gapped to .8 minimum.

apparently the tips of these can 'bounce' under higher boost pressures and cause an ignition breakdown as i am expereincing. Have you got any input on that at all ?

I have been recommened by the shop to use Iridium ($20 per plug)

Up until today i have laughed at everyone who rushed out to use iridiums, as i saw normal plugs working fine, but to have this sudden break down has made me wonder....

[Ustasa]

Do not use iridium tipped plugs for forced induction applications. Our experience has shown them to be severely lacking when it comes to boosted engines. The tips usually break off then the plug is cactus causing all sorts of misfires.

[GTS-t VSPEC]

Don't use the resistive types, the ones with R in the name.

I used to have BCP6E's in mine, and now with 400+rwhp I use BCP7E's, both were gapped to 0.67mm, and I've not had any problems:D

[cjsewell]

Swaped out your coil packs? They seem to be a common problem.

[Skyrine-Dave]

i think they are gonna try some expensive ass plugs tomorrow :S

doubt its a coil pack, never had a problem before, and as stated, was running fine minutes before this current break down happened.

[Steve]

What fuel pump are you running? does EMS have fuel cut?

[Skyrine-Dave]

fuel pump: Walboro 550hp

EMS has a fuel cut i think as a rev cut. But the rev cut both hard and soft have been raised to the 7000rpm range.

[blind_elk]

The igniter modules sometimes develop problems and break down when they get a bit hot.

[Skyrine-Dave]

Dyno Day 2: No result

ok they put in iridiums, didnt fix the problem.

The car did 1 ramp and was nice and clean, BUT STILL ONLY 206hp on 11psi!!!! WTF

car went for another ramp... and the breakdown appeared again.

The place is pissed off and so am i. Platnum plugs are being tried tomorrow.

[GTS-t VSPEC]

Yeah, it's starting to sounds more like either coil pack or the igniter module, I doubt the different plugs will help now.

[Steve]

well if its not fuel, its most probably ignition.

I dont want to tell pork pies, but I have heard off this forum that the EMS wastespark setup was attributed to frying coilpacks. I have only heard of it the once.

As GTSt suggests, probably a good idea to be looking there next. If you know someone with a skyline see if you can borrow there coilpacks for a couple of dyno pulls - will soon enough tell you if that is where your problem is.

[Skyrine-Dave]

last dyno tune we swapped all coil packs due to a missfire

all coil packs were good... the miss fire was an error in their tune!

i am wondering about the actual ignition module now.

Also...

the 1:1 gear in my car is 3rd. Should the dyno run be made in 3rd gear, or is it 4th gear no matter what ?

[Skyrine-Dave]

ok for those interested:

The ignition break down was actually the car getting too much fuel! yet the AF were 12.1:1

Dyno guy took the car for laps around the block takeing fuel OUT!, said the car seemed heaps better and was running alot better.

Comes back to the dyno, does 1 ramp, 11.1:1 AF !!... taking fuel out made the car run richer! We are both stumped as to why this happened.

very weird indeed. Should have the car back end of today, tomorrow morning at the latest

[GTS-t VSPEC]

Sounds weird, are they sure there sensor is working properly?

[Skyrine-Dave]

yeah all sensors there.

My guessing is that somehow the fuel limits on the EMS were set too high, and the EMS thought it wasnt possible to supply anymore fuel above what it had, so it imposed a fuel/ignition cut.