98ka24det
01-03-2009, 09:50 PM
ive got the jwt ecu with z32 maf and 615cc inj program.
At 1st when i got it put on it was gold, idle was rock solid. After few yrs i noticed that my idle started to get rough and noticed that my wideband was getting leaner and thats why my idle was acting up. So i went to the afc and started to add fuel at idle rpm's (800-1000)...
As time went by the idle got worse and i kept having to add more and more fuel. now im at +50 % on the afc and i cant get the wideband to go any richer than 15 flat. Sometimes it will lean out into the 16-17's and thats when the idle goes to crap. And sometimes it will cause a mis-fire, this mis-fire will throw the idle off whack and the idle will start to jump up and down to the point where the motor will stall out unless i blip the gas pedal to stop and clean it up.
What i also noticed somewhere around the time that the afc being at + 30% fuel, on COLD start ups, the motor will crank up, rev to 1400 rpm, then all of a sudden the rpm's will drop to 600 rpm and start jumping like a washing machine.... while its doing this, the vacuum will read like 15 and afc sits at 14.7 flat and doesnt budge. 10 seconds later the idle will smooth right out, vacuum goes to 20 and rpm's rise back to 1400 until the motor warms up and the idle slowly drops back to 800.
i have sent the ecu chip back to jim wolf and of course they found nothing wrong. So im clueless as to WHY i have to add 50% fuel on the afc to get this motor to idle right.... but when i go wot, the fuel is fine. it will run 10's under wot with the afc at 0 for hi throttle tune, then ill just lean it out and get it to flat 12's.
But very odd... at idle i have to add tons of fuel but wot, it runs pig rich.
At 1st when i got it put on it was gold, idle was rock solid. After few yrs i noticed that my idle started to get rough and noticed that my wideband was getting leaner and thats why my idle was acting up. So i went to the afc and started to add fuel at idle rpm's (800-1000)...
As time went by the idle got worse and i kept having to add more and more fuel. now im at +50 % on the afc and i cant get the wideband to go any richer than 15 flat. Sometimes it will lean out into the 16-17's and thats when the idle goes to crap. And sometimes it will cause a mis-fire, this mis-fire will throw the idle off whack and the idle will start to jump up and down to the point where the motor will stall out unless i blip the gas pedal to stop and clean it up.
What i also noticed somewhere around the time that the afc being at + 30% fuel, on COLD start ups, the motor will crank up, rev to 1400 rpm, then all of a sudden the rpm's will drop to 600 rpm and start jumping like a washing machine.... while its doing this, the vacuum will read like 15 and afc sits at 14.7 flat and doesnt budge. 10 seconds later the idle will smooth right out, vacuum goes to 20 and rpm's rise back to 1400 until the motor warms up and the idle slowly drops back to 800.
i have sent the ecu chip back to jim wolf and of course they found nothing wrong. So im clueless as to WHY i have to add 50% fuel on the afc to get this motor to idle right.... but when i go wot, the fuel is fine. it will run 10's under wot with the afc at 0 for hi throttle tune, then ill just lean it out and get it to flat 12's.
But very odd... at idle i have to add tons of fuel but wot, it runs pig rich.