is my ECU bad?

sgt.stinkfist · 09-13-2011, 05:44 PM

long story short, my car has being developing a dead/1 rotor mis at random, happens mostly on light throttle and sometimes at idle, revs fine and accels fine through WOT. i scoped my injector signals at the ecu, and when the mis happens the front primary injector signal drops out completely, while the rear is operating fine. when i snap the throttle, the front injector starts working again.

the wiring is ok, as i tested and rewired the harness to fit in an FB chassis. 12v at all injector clips and >.1 ohm resistance from the clips to the ECU plug.

the ECU is an N326...

could my ECU have a bad injector driver? or is there some other sensory input to my ECU that i dont know of, that is making it drop the primary injector?

RETed · 09-14-2011, 05:30 AM

1) Are you able to pull error codes from your set-up?

2) Used non-turbo FC ECU's are cheaply and easily available for most people.
Are you able to get another one to swap in and check?

-Ted

sgt.stinkfist · 09-24-2011, 01:08 AM

i think i found that my problem was due to an early second stage decel fuel cut. i tried different ecus, with the same problem, then i tried an un-modded TB and the issue went away. it seems that the TPS, dash pot and both thottle stop settings combined to give the ECU improper inputs making it think i was tipping back into the throttle after a decel event causing it to cut front rotor fuel. the fuel cut issie is gone, but now i have a rediculously low idle speed. i, with the new throttle body am idling around 500 rpm, with the idle speed screw turned all the way out...im suspecting a vac leak that im gonna chase down tomorrow

09-13-2011, 05:44 PM	#1
sgt.stinkfist The Newbie Join Date: Jun 2011 Posts: 16 Rep Power: 0	is my ECU bad? long story short, my car has being developing a dead/1 rotor mis at random, happens mostly on light throttle and sometimes at idle, revs fine and accels fine through WOT. i scoped my injector signals at the ecu, and when the mis happens the front primary injector signal drops out completely, while the rear is operating fine. when i snap the throttle, the front injector starts working again. the wiring is ok, as i tested and rewired the harness to fit in an FB chassis. 12v at all injector clips and >.1 ohm resistance from the clips to the ECU plug. the ECU is an N326... could my ECU have a bad injector driver? or is there some other sensory input to my ECU that i dont know of, that is making it drop the primary injector? __________________ 82 GS- GSL rearend, ported S4 13b, MSD 6AL, walbro 255, 460/550cc injectors, 2" dual exhaust, 3 row aluminum radiator w/ taurus E-fan 85 20v ST AE86 - sold to fund the 82 86 RX-7 GXL - donating parts to the 82 everything else - scrapped to fund the 82

09-24-2011, 01:08 AM	#3
sgt.stinkfist The Newbie Join Date: Jun 2011 Posts: 16 Rep Power: 0	i think i found that my problem was due to an early second stage decel fuel cut. i tried different ecus, with the same problem, then i tried an un-modded TB and the issue went away. it seems that the TPS, dash pot and both thottle stop settings combined to give the ECU improper inputs making it think i was tipping back into the throttle after a decel event causing it to cut front rotor fuel. the fuel cut issie is gone, but now i have a rediculously low idle speed. i, with the new throttle body am idling around 500 rpm, with the idle speed screw turned all the way out...im suspecting a vac leak that im gonna chase down tomorrow __________________ 82 GS- GSL rearend, ported S4 13b, MSD 6AL, walbro 255, 460/550cc injectors, 2" dual exhaust, 3 row aluminum radiator w/ taurus E-fan 85 20v ST AE86 - sold to fund the 82 86 RX-7 GXL - donating parts to the 82 everything else - scrapped to fund the 82