00paul

I have a supercharged 403 in an 07 trailblazer. During cool ambient temperatures, the idle bounces from 1200 to 400. Sometimes stalls. The gas pedal sometimes does nothing for a second or two unless pushed at least 1/4 travel. Some days it fires up and idles fine. It seems to be mostly cooler days.

I have a wideband gauge bouncing from 13 to 17 and spark log is like 4 to 31 when its idling poorly. When smooth, its 14.5 to 15.2 afr and spark is around 18 to 21.

Im having trouble finding a table to correct this. I tried adjusting maf values based on the scanner log, but the afr and ignition timing still wont hold steady.

Anyone have some advice on correcting this idle?

68Formula

Still learning, so I'll let the others chime in on the heavier stuff. But for starters, shouldn't your engine size be changed to 0.825L/cyl?

00paul

I changed the engine size with hp tuners then did some more data logging. My wideband is reading 12.8 under wot before and now read 13.2. Short term fuel trims are all over the place at various loads. I didnt do the original tune. Im going to follow some guides and go through the maf calibration and ve table before I chase this much further

00paul

I got the idle much happier, still bounces slightly, but no longer wild. Added to the idle airflow vs ect table under the base running airflow section. Multiplied by 1.4 at lower temps seemed to stabilize my erratic idle when cold. Not sure if there was a better way to fix it, but at least its not hunting and stalling anymore.

Facetuned

I would be concerned with the 12.8 under WOT, this is a supercharged setup correct?

00paul

It is supercharged. I adjusted the maf table a bit and have the wideband reading 11.8 under wot now. I am not sure how much to trust the wideband. It came installed on this vehicle and I dont know how long its been since calibrated. I started another thread trying to get help calibrating the sensor without knowing what sensor it is.

Facetuned

I replied to it as well i think, do a free air calibration same as you would any other brand. also post up your .cal file it will help better resolve your problem.
could be something simple in the air flow or ignition map.

00paul

Im brand new to tuning. What is the .cal file? I only see the option to save my files from vcm editor as .hpt. Vcm scanner shows files as .hpl.

andy burdess

you need someone professional to help you. Supercharger adds a bit to the mix. Can you log and email back and forth?

00paul

Yeah I can log and email. I need to get my wideband situation straight. Im trying to figure out how to free air calibrate it and it doesnt do anything on my gauge when i try. I might pull the one off my camaro or get a new one with serial output for laptop data logging.

LilJayV10

iTrader: (39)

Personally I'd get a new sensor and free air calibrate it. Cheap insurance compared to what could happen.

Also, verify it's wired correctly. I've seen people do some dumb **** before. Some W/B, especially Innovates stuff is more particular about their wiring than others.

00paul

I forgot to update this. I replaced the throttle body and it fixed my idle issues.