Dead idle "tip in" question for DaveW

[GMC Truck]

Smallblock with bigblock tbi unit and bpw set at 123 truck runs really great with blm's around 126 low speed and 129 cruising. However when cold (80degrees) upon startup if you touch the throttle at all untill the IAC closes (warm engine) the motor goes "flat" for about 3 or 4 seconds. No lean pop but the tach drops right off. After it reaches temp 140 and above you have instant throttle response with no lag or flat spot at all. I have changed lots of things and am now just guessing trying to get it out. The problem is you only get a minuet or so to try cause it warms up. You cannot drive this truck untill it warms up, if you load the engine (release clutch) and hit the gas its dead! Any ideas???

 

[dave w]

I think I would try with one of these settings first. I would start with Power Enrichment Mode Delay, maybe try 1.5 seconds, then 1 second. I would then work with the TPS% Threshold settings, drop from 50% to 35% maybe 25%? Lowering the Bypass Power Enrichment Delay to 1000 RPM would an option also. I only change one thing at a time. Determine which of the three makes the problem go away, or not so noticeable. It could take an adjustment to all three.

dave w

 

[GMC Truck]

I don't have the "power enrichment mode delay"? I have something called "power enrichment delay timer" which i bet is the same thing? Mine is set at 10 sec but if I compare to a 454 bin its set at 3 sec. I will try playing with these and give em a shot. I have burnt so many chips this past week its not funny! All for just this stumble it runs great everywhere else in the powerband. Thanks i'll keep you posted.

 

[dave w]

I own an Ostrich 2, helps save chip burning swapping for the kinds of tuning you are working through.

dave w

 

[GMC Truck]

Ok I looked closely through my program and I only have the "power enrichment delay timer" in my program? Whats that used for?, and its set for 10 seconds that seems like a bunch if you talking throttle response time. I also noticed that theres "Accel enrichment" and "Power enrichment" which one for tip-in at idle??

 

[dave w]

Ok I looked closely through my program and I only have the "power enrichment delay timer" in my program? Whats that used for?, and its set for 10 seconds that seems like a bunch if you talking throttle response time. I also noticed that theres "Accel enrichment" and "Power enrichment" which one for tip-in at idle??

I have both TunerPro and TunerCats. If I'm remembering correctly, you are using TunerPro.

Here are a couple screen shots. One is .bin ASCN 1988 GMC 5.7 with MT. I read ASCN .bin directly from the vehicle PROM. The other .bin is from a performance 454 .bin I read directly from the PROM. I think maybe there is a difference between the version TunerPro I have and the TunerPro you have? I think having the screen shots to compare / study might help? Accel enrichment is for tip-in at idle. There are two types of Accel enrichment TPS & MAP.

dave w

 

[GMC Truck]

I DO seem to have all the same functions but mine are just labeled diffrently. Your %TPS threshold VS RPM for PE mode is called "TPS needed to enter power enrichment VS RPM" in mine. I forgot how to do the screen shots that you told me once before, duh?