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

DoctorDex · 11-10-2006, 01:35 PM

I got off the phone today with AvPro and they don't think the problem is caused by the ECU. I'm not sure what to do now. The problem seems to be getting worse and it the affected rpm range seems to be spreading, it now misfires between 2400 - 3200 rpm.

It doesn't appear to a closed loop to open loop issue, because if I'm driving in a low enough gear in closed loop, above 3200 rpm and below 2400 it runs like a champ. If I go WOT ~ 2000rpm and accelerate in open loop it still wants to stutter in the 2400rpm - 3200rpm range, its just not as noticeable.

Has anyone done an EGR blockoff and encountered this problem? I'm curious as to whether or not these symptoms could be caused by a leaking/poorly functioning EGR valve?

I had previously disconnected my EGR valve, so it would stay in the "closed mode" all the time. However, I noticed when I'd boost, I was seeing an extremely lean rear bank. It turns out boost was spilling into my exhaust through the EGR pipe. I cleaned the EGR valve and did another run at WOT, it was still leaking into the exhaust. The problem was only cured when I reconnected the EGR valve. However, since the EGR valve is acting so screwy I think I'm going to get a rid of the thing all together. Maybe this will help cure the high (7 - 10) counts (x5-6 times) I see from time to time, when gradually accelerating.

Declan

11-10-2006, 01:35 PM	#57 (permalink)
DoctorDex Forum Member Join Date: Jul 2005 Location: Edmonton, AB Drives: '91 VR4 Trader Rating: (13)	Re: Lean Misfires at 2400-3200 rpm I got off the phone today with AvPro and they don't think the problem is caused by the ECU. I'm not sure what to do now. The problem seems to be getting worse and it the affected rpm range seems to be spreading, it now misfires between 2400 - 3200 rpm. It doesn't appear to a closed loop to open loop issue, because if I'm driving in a low enough gear in closed loop, above 3200 rpm and below 2400 it runs like a champ. If I go WOT ~ 2000rpm and accelerate in open loop it still wants to stutter in the 2400rpm - 3200rpm range, its just not as noticeable. Has anyone done an EGR blockoff and encountered this problem? I'm curious as to whether or not these symptoms could be caused by a leaking/poorly functioning EGR valve? I had previously disconnected my EGR valve, so it would stay in the "closed mode" all the time. However, I noticed when I'd boost, I was seeing an extremely lean rear bank. It turns out boost was spilling into my exhaust through the EGR pipe. I cleaned the EGR valve and did another run at WOT, it was still leaking into the exhaust. The problem was only cured when I reconnected the EGR valve. However, since the EGR valve is acting so screwy I think I'm going to get a rid of the thing all together. Maybe this will help cure the high (7 - 10) counts (x5-6 times) I see from time to time, when gradually accelerating. 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)