lt1 idle problem need advise - fresh build
04-09-2010, 08:25 PM
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lt1 idle problem need advise - fresh build hey guys i have a freshly built 383 Lt1 and it will not idle. It runs pretty good but it just wont idle. Iv read about drilling the iac hole out, but i cant find a good write up on how exactly to go about doing it. Or would it be better to mess with the little throttle adjustment screw on the cable bracket to try and get it to idle that way. The only trick i think i don't want to do is to drill a hole directly into the throttle blade, that just doesn't look right to me. Its a summit brand 58mm TB. Im not throwing any codes and have driven the car the past two days around the block a few times and it still isn't throwing codes. any info on this would help me greatly. thanks car is obd2 if that matters
04-09-2010, 08:45 PM
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unless it moved (because i cracked part of the ear off when i was reaming the hole out) its set at .67... i need to get a new one but that one works for now just the ear is cracked...
04-09-2010, 08:53 PM
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I have the same throttle body and I adjusted the tps but if yours is reading right just use that screw on the other side. If i were you if you have room put a nut on it to lock it down because mine backed out on the highway and fell out
04-09-2010, 08:56 PM
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cool.. maybe ill try that then... thanks for the head up on the lock nut thing... i mean im really hoping i can get this thing to idle... i have a funny feeling its a tune problem though, but im not sure yet... i mean i have to give the car gas to start it... which is weird for a fuel injected car...
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04-10-2010, 08:15 AM
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yea its had a pcmforless tune... i would like to get it to a dyno sooner or later to get a "real" custom tune for the car... pcm for less is usually good but iv hear stories here and there of people having problems with them... i will check to see if gas is coming out of the regulator also..i have to go out to work on my saturn today so maybe ill mess a little with this also... thanks for the help... so... so far nobody is recommending the IAC drill mod
04-10-2010, 10:50 AM
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never got a good reading on them... ill have to wait till next week to borrow my freinds scanner to check them... they were like super low during first start up something like 9 or something but that was a few months back in like november and they haven't been checked since...
04-10-2010, 11:10 AM
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open the blades and re-adjust tps. that's also what i had to do after my dyno tune. idled good while it was cold but after it warmed up...it had a little harder time breathing.
04-10-2010, 11:28 AM
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well i just adjusted the blades a little and started her up... and she seemed to idle pretty good and strong... but then i went for a ride and sure enough she started to die when i came to a stop sign... i don't know whats wrong with it... i pulled back in the drive way and shut her down and then started her up and she started to idle again... i think im going to try and put some more gas in maybe something with the pump and its starving for gas when its moving... i don't know?? any ideas.. im not to hip on the pcm stuff yet...
04-10-2010, 12:39 PM
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crap i didnt think about that... ok i have to wait for that scanner... any idea why it would idle in the driveway but cut out when i start to drive it under load...
04-10-2010, 12:39 PM
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well i just adjusted the blades a little and started her up... and she seemed to idle pretty good and strong... but then i went for a ride and sure enough she started to die when i came to a stop sign... i don't know whats wrong with it... i pulled back in the drive way and shut her down and then started her up and she started to idle again... i think im going to try and put some more gas in maybe something with the pump and its starving for gas when its moving... i don't know?? any ideas.. im not to hip on the pcm stuff yet...
04-10-2010, 01:30 PM
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well i have the tune to idle at 900rpm... with the way the blades are set now its at around 1000rpm... but its just wierd that it doesnt idle when out on the road... only guy i know that can do a good job tuning is like an hour away and the car is just not drivable that far because of the idle issue
04-10-2010, 02:39 PM
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once you adjust the TPS back where it needs to be I think you're idle will come down closer to the 900 the ECM is commanding. I noticed this as I was adjusting mine the other night. I would crack the blades open, RPMs would increase to 1200-1400, then I would adjust the TPS back to near .4v and the idle would come down. Not sure why you would be having trouble with it cutting out under load but I don't quite understand the statement either. Do you mean when your off the throttle coasting to a stop? Make sure you do the adjustments in closed loop also. If you can get a cable, go for a drive and log it, then post up the log or email it.
04-10-2010, 03:34 PM
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ok one of my buddies may have a cable and laptop that will work if he will let me borrow it... yea i mean that when im coasting to a stop it wants to cut out... but if im parked in the driveway it idles not to bad... but like i said i have to wait a few days for the scanner so ill post up my iac counts and whats going on in there when i get that... again thanks for all the help guys i really appreciate it
04-12-2010, 07:38 PM
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ok.. well my buddy came over today with the scanner and we hooked it up.. .and my IAC counts were through the roof (130 at idle)... so we decided to start drilling the hole through the TB where the IAC goes to let some air through... and sure enough it started coming down did this about 4 times and now my iac count is around 45 and the car is running great... starts up without having to add throttle... and idles when coasting to a stop... im going to go back in maybe tomorrow and go one more size bigger on the hole to get them to get down around the 35 area which i think they are sopposed to be? unless 45 is good because its running really good now.. so thanks for all the help... i thought id let you guys know how it went...
