so the car doesnt keep a stable idle after a long drive or a hard boosting drive.

it doesnt do it on a cold start,only when the car is shuted down and restart after a hard drive or long drive.

here is a video of it (2min footage ) with what the idle is doing what vac its pulling and what the AFRs are doing
http://www.youtube.com/watch?v=DtEeh...1&feature=plcp

setup is.

haltech ps1k
ls2 coils
mild street port
850/1680 injectors
RP fuel pump
trigger wheel kit

no smog stuff.

thanks

 

I had that issue also but with a PFC. Regardless it was two things:
The IAC was operating way outside of it's mid range at hot idle; easily fixed with throttle body air screw adjustment while monitoring IAC duty cycle.
Heat soak on the IAT sensor. Relocate to area away from engine heat. I installed a fast acting sensor in elbow just before the throttle body.

 

Thanks very much.. I have a fast iats but its still in stock location ,guess thats not good

 

I have the same issue on mine, however my afr's get richer instead of leaner like yours. I also have a fast IAT in the stock location with a PFC.

I never took into consideration heat soak for that problem. I'm gonna monitor the IAT duty cycle and see what it's doing.

 

engine is most likely surging when it gets leaner than about 13.5:1 . The fans may be cycling on and off as well, which typically changes load on the engine and as a result changes the fuel and timing.

Tweaking the air temperature compensation table (and probably the main fuel map) can help with this. You're a little limited in flexibility because you can't adjust fuel air temperature compensation separately for low and high load driving.

 

is it bad that the engine surge like that ? when it does it and i force it to drive , i have to really peddle the gas to take off smooth ,or eles it whould stall on me .

but free reving it a few times does help the idle become normal

 

not an big issue , but it does get on my nerv somtimes...IE when i have a female passeneger.

 

sounds like the car needs street tuning, that's all.

wait I just realized you have a Haltech. I didn't read closely but rather I assumed you had a PFC w/o the Datalogit laptop interface because this was in the general 3rd gen section. Take some data logs when it happens and post your map.

 

the car is street tuned but only for wot boosting,not enough detail tuning . will get to that.

is it bad for it to surge like that ?

 

I can't see it causing long-term harm, it will just annoy the crap out of you and perhaps attract unwanted attention.

 

got cha! thanks..

i did however found some interesting things tonight, while i was waiting at a drive-through
the car started to do the funky idle again(when the fans turn on it starts doing it ).
and some how i just decided to turn off my headlight,and the idle went back to normal( even with fan on )it only droped to idle by 100rpm or so.. thats why in the day time while its warm out side the car runs better then at night..

could it be a voltage issue ? like a bad battery or a bad alt? i notice with out the headlight and stereo and all the other electric stuff going on the car idles 10x better

thanks

dave

 

Could be alt. Could be a bad ground(s). There's also something by the ecu that controls this but I forgot. Mahjik knows.

 

any word as to what fixed this? or what could fix it with the ecu? mine has similar issue whenever lights are on the idle gets irregular along with other electronics causing idle issues