3000GT/Stealth International Message Center - View Single Post - Lean Misfires at 2700-2800 rpm

DoctorDex · 10-09-2006, 03:31 PM

I also have new caps.

I question whether or not the problem is ECU related. If it were ECU related, one would think that changing the % overclock would shift the misfiring rpm point up or down. I have tried different speeds of crystals and they have no effect on the Rpm point at which it misfires.

I'm also wondering if this issue of "spark blow out" on my rear bank is related. I've never had issues, to this degree, with spark blow out. At WOT, my rear o2 voltages are dropping to 0.60V between 4600-6000rpm and then they go back to 0.91V from 6000rpm - 8200rpm. Like I said before, it doesn't feel like spark blow out and the o2 voltages aren't bouncing around. However, I have noticed that my timing will start zig zagging a bit in the 4600-6000rpm range when it is blowing out. The strangest part about it all, is that if I do back to back runs, on one run it'll bounce between 0.89-0.91V and the next it drops all the way down to 0.60V.

Any ideas?

If I was to try swapping in an ECU from a 93 VR4 (with a 95 engine), would this mean that he is using a 95 ECU or a 93 ECU and would I have to make any changes to my car or his ECU, so it'll work with the CAS?

Thanks.

Declan

10-09-2006, 03:31 PM	#24 (permalink)
DoctorDex Forum Member Join Date: Jul 2005 Location: Edmonton, AB Drives: '91 VR4 - RIP Trader Rating: (13)	Re: Lean Misfires at 2700-2800 rpm I also have new caps. I question whether or not the problem is ECU related. If it were ECU related, one would think that changing the % overclock would shift the misfiring rpm point up or down. I have tried different speeds of crystals and they have no effect on the Rpm point at which it misfires. I'm also wondering if this issue of "spark blow out" on my rear bank is related. I've never had issues, to this degree, with spark blow out. At WOT, my rear o2 voltages are dropping to 0.60V between 4600-6000rpm and then they go back to 0.91V from 6000rpm - 8200rpm. Like I said before, it doesn't feel like spark blow out and the o2 voltages aren't bouncing around. However, I have noticed that my timing will start zig zagging a bit in the 4600-6000rpm range when it is blowing out. The strangest part about it all, is that if I do back to back runs, on one run it'll bounce between 0.89-0.91V and the next it drops all the way down to 0.60V. Any ideas? If I was to try swapping in an ECU from a 93 VR4 (with a 95 engine), would this mean that he is using a 95 ECU or a 93 ECU and would I have to make any changes to my car or his ECU, so it'll work with the CAS? Thanks. Declan __________________ '91 VR4 - Modlist: DR650R turbos, Snow stage 2D alky kit, DSM SMICs, blowthrough ported LT1 MAS, Dejon Tool intakes & y-pipe, Blitz DSBC Spec R, HKS SSQV BOV, PTE 580cc injectors, Dual feed fuel system with Aeromotive FPR & filter, Hotwired Supra pump, ek2mfg plenum spacer, HKS DLI, MSD Wires, Apex'i S-AFC II, MAFTranslator, Turbobob ECU, Scanmaster III, LC-1 WBO2, ESP downpipe, Vac/EGR delete, Gutted precats and test pipe, Maximal solid mounts, 300m 18 spline output shaft, Centerforce Dual Friction clutch, RPS flywheel, GC coilover conversions with helper springs, Powerslot slotted rotors, Goodridge SS brake lines, Hawk pads (front), Stillen metal matrix pads (rear)