2jz missfiring when winding up boost

[GU11TY]

ok guys just trying to get my car ready for toymods drag now
now with my 2j which has been built up it was running 44rwhp on 15 psi
now it only had a.,63 rear housing on it and the turbo was maxed out
so the only things ive changed now is
new exhuast system
.82 rear housing
and sard fuel pump
now it started stuttering on 15psi but put it in for a tune and its fine on 15 now
but wen i want to wind it to 20 it starts missfirng
im running a microtech ltx16 ecu with new bosch coils and leads and new spark plugs
the only thing im thinking is if its getting enough fuel because this sard fuel pump i think is suppsed to run its own loom where as in this car its just plugged into the original loom
the tuner tested the fuel pressure and its 55psi and should be running at least 65 he said
i have 870cc injectors
do you think fuel is the problem because i dont know anything else it could be

[pandaah]

tried gapping your plugs slightly smaller?

[GU11TY]

tried 0.6 and 0.7

[Duk]

the tuner tested the fuel pressure and its 55psi and should be running at least 65 he said

Correct any fuel system related problem first, tho you never mentioned if its running lean
After that, maybe you should be looking at a capacitive discharge ignition system.

[nemesis86]

I am having the exact same trouble with my 2jzgte. I'm also running microtech ecu with new bosch coils, single turbo setup and supporting mods etc.... My car managed to make 415 hp on 17psi before missfiring. Tried different plugs with different gaps and still no good. Any help would be greatly appreciated also.

[GU11TY]

wat fuel pump you running?

[Phoenix01]

I had the same problem at around 435ish hp. I ended up solving the problem with AEM pencil coils and an EMS 6 channel CDI. Possibly excessive but it certainly eliminated the missfire and I doubt spark will ever be a problem again. Now running 490ish hp at 22psi (GT3582R with a .82 rear housing).

[nemesis86]

wat fuel pump you running?

I'm running a walbro to my surge tank and then a bosch 044. I don't think fuel is the problem though

[GU11TY]

I'm running a walbro to my surge tank and then a bosch 044. I don't think fuel is the problem though

yeh i got a sard fuel pump and i was thinking about getting a surge tank bosch 044 to try and solve the problem but hmm you still got them problem

I had the same problem at around 435ish hp. I ended up solving the problem with AEM pencil coils and an EMS 6 channel CDI. Possibly excessive but it certainly eliminated the missfire and I doubt spark will ever be a problem again. Now running 490ish hp at 22psi (GT3582R with a .82 rear housing).

so are you saying my bosch coils still wont do it or how do you think i can solve the problem cause yeh anything over 440hp for me it starts misfiring

[manny]

yeh i got a sard fuel pump ...

What are your AFRs like when it starts misfiring?
The pump caught my attention as I dealt with this issue in my Soarer some 7 or 8 years ago chasing big numbers - if it's same same Sard pump they used to sell years ago, it's just a rebadged USDM MKIV Supra Denso 2JZ-GTE fuel pump and definately needs some decent supply and earth wires to it to minimise loss and supply the necessary high current drawn - at 13.5 Volts it's claimed at 16Amps @ 43 psi or up to 19Aamps @ 70 psi!
Use the existing power feed signal to the pump to trigger a 30amp relay near the pump and pull a new direct power feed fused off the battery.
Match the earth with the same thicker grade wire you use for the supply.

[GU11TY]

What are your AFRs like when it starts misfiring?
The pump caught my attention as I dealt with this issue in my Soarer some 7 or 8 years ago chasing big numbers - if it's same same Sard pump they used to sell years ago, it's just a rebadged USDM MKIV Supra Denso 2JZ-GTE fuel pump and definately needs some decent supply and earth wires to it to minimise loss and supply the necessary high current drawn - at 13.5 Volts it's claimed at 16Amps @ 43 psi or up to 19Aamps @ 70 psi!
Use the existing power feed signal to the pump to trigger a 30amp relay near the pump and pull a new direct power feed fused off the battery.
Match the earth with the same thicker grade wire you use for the supply.

do you know how to do the wiring
ill pay you to come out and do it?

[manny]

do you know how to do the wiring
ill pay you to come out and do it?

Yes I do know how to do the wiring as did mine many years ago and have since shown numerous guys on the ALSC how to do it themselves.
PM me your number and I'll call you tomorrow to discuss how it's done.

[Phoenix01]

so are you saying my bosch coils still wont do it or how do you think i can solve the problem cause yeh anything over 440hp for me it starts misfiring

Not necessarily. I'm just sharing my experience that occurred under similar circumstances. My stock coils seemed to be causing the issue under very similar conditions to what you're describing minus the fuel system issues that you mentioned.

I'd investigate the fuel pressure problem first as you and others have said. But in nemesis86's case I think spark is the problem.

I only went as crazy as I did because changing coils is one thing, but coils will only go so far when using the factory ignitor. I didn't have much experience in the area and I really didn't want to spend a few dollars only to find the limit of upgraded coils is just a few pounds of boost higher than where the stock coils gave out. But now with 50kV across the spark plugs I'm pretty certain anything that enters the cylinders is going to burn.