backfiring under boost, only at WOT

[hungryjoseph]

vacuum leak, coilpacks

[burntricer]

0 leaks (tested with a boost leak tester) coil packs are all good, and mostly new

[virus77]

the plug u are using is pregapped to .040 designated by the 11 at the end of the model number, could be that you are running to much gap... bring em down to .030 and see what happens, its worth a shot although 5 psi is pretty low and shouldn't cause blow out.

[burntricer]

anything over 5psi and it feels like i get a miss,

i gapped my plugs to .28

[hungryjoseph]

the grounds on your 'packs could be bad and did you buy the coilpacks new or used?

[burntricer]

'packs are grounded right to the intake mani. however. its just the one wire...

[IanS]

Did you get them securely bolted down yet? Gap is good, Plugs good, no boost leaks, coil packs are new, If bolting them down dosn't fix it, I would start from scratch, do the easy stuff, clean the MAFs, check the MAFs voltage, check TPS voltage, check fuel pressure, and check for ECU codes.

[burntricer]

oh man, i just realised your in minneapolis! haha, ill meet you in duluth and you can check out the car! haha im up in Thunder Bay

anyway. yeah there bolted in tight. Heres where i think the problem lies. i was talking to the guy i got the motor from, he asked me if i had the stock tune back engaged (he was running a GT2871R, HKS cams, 550 CC injectors, with an SAFC, wideband and Daughterboard...) and he was saying that if i pulled the daughterboard out that it would go back to stock tune. so i pulled the daughterboard, and i re-set the ECU and no changes.

But what im thinking is the reason im running rich, and hardly able to boost, is im running into putting too much fuel in because of the tune... sound plausable?

how would i go about tuning a daughterboard? and does anyone have the stock values for an SR with the KA24E MAFS with the 320 CC injectors?

[IanS]

stock injectors are 370CC, and if it was tuned to run 550cc injectors and you are using 370s it wouldnt be putting in enough fuel, it would be leaning out and the motor probubly would have blown by now. I would say try and find yourself a known good stock ECU and give that a try, If I had a weekend off work I would meet you in duluth and you could try mine, but I am working 9 days on to every 1 day off right now, so I wont be going anywhere anytime soon, good luck.

[burntricer]

changed some things...

300ZX fuel filterRe-gapped plugs to .28bloted down coil packshooked up my stock boost control solenoid

now im running pig rich. i have no vacuum leaks, no boost leaks, BOV is recirc'd

wtf is this cars problem

i tried to pull codes but the little screw in my ECU just spun and spun somemore.

im totally at a loss!

[hungryjoseph]

did those coilpacks come with the motor or did you get newones? and were they bought used or new? 90% of the time i see problems liek this, it'sthe coilpacks...

[burntricer]

they came with the motor, however the guy i got the motor from, replaced them last winter with brand spankin new ones.

[92SR20S13]

Get bkr7e and gap to 0.28..im having the same problem..but i used brk6e aswell and what seemed to be happening is that once i come onto high boost (15psi) the car will jerk and sputter but still somewhat go..i think the spark is getting blown out and im getting to much fuel. try going with heatrange 7 and maybe it will clear things up

[burntricer]

coil packs tested, they all check out good