timloomis
20+ Year Contributor
- 925
- 15
- Jan 28, 2003
-
duncan falls,
Ohio
I can not get my WOT tuned right. I'm running 10 psi more base fuel pressure with the N/T FPR on my RC 550's. That turns them into 640's, which I have the MAFT set for.
My fuel trims were around 100% until today when they all went lean for some reason, around 127%. I just installed a new Walbro 190 and it's rewired, and I have a new fuel filter.
My logger shows my IDC is around 90% at ~5500 rpm on. Narrowband O2 voltage is at 0.89 volts, and the logger maxes out the 1606 HZ airflow at ~4900 RPM. I'm still on the 14b at 17 psi. It's still knocking 10 or so counts even with adding 5 clicks with the MAFT WOT knob.
Thought it was rich knock so I backed it off 4 clicks, and knock went nuts. Also zero boost leaks. I've changed 2 GM MAS sensors just to be sure, and I'm still having this problem. This has to be a bad MAFT right?
I don't want to spend 150 on an SAFC unless I have to. There's no way in hell I'm maxing out 640's at 17psi with an unported 14b. Timing is right on at 5* BTDC too.
My fuel trims were around 100% until today when they all went lean for some reason, around 127%. I just installed a new Walbro 190 and it's rewired, and I have a new fuel filter.
My logger shows my IDC is around 90% at ~5500 rpm on. Narrowband O2 voltage is at 0.89 volts, and the logger maxes out the 1606 HZ airflow at ~4900 RPM. I'm still on the 14b at 17 psi. It's still knocking 10 or so counts even with adding 5 clicks with the MAFT WOT knob.
Thought it was rich knock so I backed it off 4 clicks, and knock went nuts. Also zero boost leaks. I've changed 2 GM MAS sensors just to be sure, and I'm still having this problem. This has to be a bad MAFT right?
I don't want to spend 150 on an SAFC unless I have to. There's no way in hell I'm maxing out 640's at 17psi with an unported 14b. Timing is right on at 5* BTDC too.
