if I'm drivnig along & I come to a stop, my idle will sometimes drop as low as 450rpm & than recover, I've looked at my IAC follower tables, MPH vs. iac tables aswell, they look pretty good, I have 27* advance etc... do you guys think my IAC valve is just slow? it gets bettter the more I drive, but if I tune the car it gets real bad again until I drive around 100kms, this is pissing me off cuz I don't like the car doing things I have little control over I thank you

help me out guys, my setup is in my sig, I'll reply to your guy's questions thanx.

 

Maybe its me but what do you mean by: "it gets bettter the more I drive, but if I tune the car it gets real bad again until I drive around 100kms"? Do you mean it is fine then it gets bad after so many miles? If thats the case then you are running rich and fouling the plugs.

Hal

 

And another odd thing. You list a ton of mods and no computer program. You can't run all that and expect the pcm to compensate, you need to have it tuned. At least turn up the idle a little, that cam needs to run a little faster at idle then stock rpm.

Hal

 

Bunker uses LT1 Edit.

Have you considered a harware problem in the TB? I know yours is pretty new. Mine is old and the bushings are worn. It means that the TB plates to not always close tight when I let off the gas very slowly and I have the opposite probem. The car revs high and only slowly comes down to idle.

I would check that there is no wiggle room from the blades.

 

No I did tune it, it get better after more driving but I'm thinking its cuz its running rich & the engine doesn't want to idle after its got so much fuel, I gonna lean it out cuz right now my blms sometimes sit at 108 I dunno I'll check.

 

I had the same problem bunker. When coming to a stop, the car would drop idle to like 500 and sometimes it actually stalled on me. Of course it fires right back up and idles fine after, until the next run & stop. After a few days it went away and instead the car started idling high around 1000 when coming to a stop almost like the throttle was sticking open, so I reset the IAC with FreeScan and it soon went back to normal. Then I noticed my BLMs were sitting at 108. So I unplugged the MAF while its running and watch the BLMs, back into the 120s, plug it back in and back down to 108 again and the idle gets real choppy. I blame the MAF sensor so I'm going to swap it this weekend with a working one and see what the result is. Give us an update if you find the culprit.

 

What are the IAC counts when this happens????? You have any log runs???? You may need to open the TB blades a bit. Do you have split blm's??? What TB? Holley isn't it, does it force idle air to the iac passage? or does it leak into the plenum?

 

Holley forces it through the idle passeges, ok today I had the weirdest thing happen, I stoped, idle went back down to 500 than jumped to 1200, than 3000, than back to 1000 & up & down up & down, than when I tried driving away it started hesitating, I figured the hesitation was from the vacum leak that was happening, my o2's would go to 900 range at that point aswell, my iac count shot from 70 all the way to 160 & stayed around 150-160 & than went back to normal, good thing I was logging, is this a bad iac or something really messed up? I don't have split blm's at idle just driving around. When the iac counts go to 160 is that the pcm telling it to go that high or the IAC going there & the computer displaying the results? LMK thanx guys.

 

Dave, I believe when the MAF is disconnected it goes into open loop and will always report blms of 128 falsely because its not reading the 02 sensors. After a restart it will also go into open loop even when the engine is warm so thats why it idles fine for a few moments. But, I don't know enough to help your problem (maybe a bad 02 sensor?).

Hal

 

what the heck is my problem? I'm gonna try my buddies TB with iac on it & stuff.

 

Found my problem, basicly you have to tune differently for a Holley TB than others since Holley pretty much redirects most of it's idle air through the IAC the IAC idle/& follower tables are useless I bumped those quite a bit & now the car runs perfect