I have pretty lousy idle quality and a frequent stalling problem when coming to a stop after cruising for a while – unless I double foot the brake and throttle.
I’m only pulling about 16” of vacuum at idle (engine warmed up of course). I have my idle A/F set at 14.55 to 1.0 (closed loop w/wideband feedback). It won’t go any leaner and still idle reliably. The injector duty cycle is only about 1.2%. Perhaps that is not enough pulse duration for the computer to be able to control the injector well?
I believe that my problem might be in the basic throttle blade setup. I followed some Accel setup information and adjusted the throttle blade to make the IAC counts read 5% to 7% bypass air.
On the Minimum IAC Position vs. Coolant Temp. (%) screen, from 80 degrees to 240, the minimum IAC is at 5.1. Out of curiosity, I jacked up the value to about 20. The idle quality improved dramatically and the pulse width went up (into the 2’s I believe). After cruising, the stalling problem seemed to be gone too.
I have read some posts that say that the IAC should be 20% at idle. If that’s where I need to be, then should I change the curve values to 20% or should I open the throttle blade wider to give me those higher counts?
FYI, my (not very radical) cam is roughly 212/206, 0.500 lift and 109 lobe separation. Injectors are high impedance 55s.
Thanks, Bob
I’m only pulling about 16” of vacuum at idle (engine warmed up of course). I have my idle A/F set at 14.55 to 1.0 (closed loop w/wideband feedback). It won’t go any leaner and still idle reliably. The injector duty cycle is only about 1.2%. Perhaps that is not enough pulse duration for the computer to be able to control the injector well?
I believe that my problem might be in the basic throttle blade setup. I followed some Accel setup information and adjusted the throttle blade to make the IAC counts read 5% to 7% bypass air.
On the Minimum IAC Position vs. Coolant Temp. (%) screen, from 80 degrees to 240, the minimum IAC is at 5.1. Out of curiosity, I jacked up the value to about 20. The idle quality improved dramatically and the pulse width went up (into the 2’s I believe). After cruising, the stalling problem seemed to be gone too.
I have read some posts that say that the IAC should be 20% at idle. If that’s where I need to be, then should I change the curve values to 20% or should I open the throttle blade wider to give me those higher counts?
FYI, my (not very radical) cam is roughly 212/206, 0.500 lift and 109 lobe separation. Injectors are high impedance 55s.
Thanks, Bob