Getting a h/c motor to idle
Getting a h/c motor to idle Ok what do I need to do to get this thing to idle?
Drill a hole in the throttle plate? What size?
Adjust the idle screw to hold the throttle slightly open?
Can it be done with just tuning? Changing what?
Stage 1 heads
228-236 .588-.578 114 +2°
All of the bolt-ons with ST 3800 converter.
It surges from 300 to 1100 a couple of times then dies. Every time.
Tuning is otherwise very good.
TIA
Drill a hole in the throttle plate? What size?
Adjust the idle screw to hold the throttle slightly open?
Can it be done with just tuning? Changing what?
Stage 1 heads
228-236 .588-.578 114 +2°
All of the bolt-ons with ST 3800 converter.
It surges from 300 to 1100 a couple of times then dies. Every time.
Tuning is otherwise very good.
TIA
Launching!
Joined: Nov 2003
Posts: 272
Likes: 0
good lord... that cam should idle GREAT, with its 114 lsa even at +2. get that thing tuned! 
what made you go with stage I heads?
edit... i forgot, i had this same problem that you are having with the little motor that is attatched to the trottle body. i forget what it is called but try UNHOOKING IT and see if it cranks and idles good. if it does then go get you a new little motor. i had this problem with my ASA cam. 226/236 110 lsa.
mike
what made you go with stage I heads?
edit... i forgot, i had this same problem that you are having with the little motor that is attatched to the trottle body. i forget what it is called but try UNHOOKING IT and see if it cranks and idles good. if it does then go get you a new little motor. i had this problem with my ASA cam. 226/236 110 lsa.
mike
i think your talking about the iac...its possible thats the problem...my 231/237 would idle as long as i had the idle screw opened alot with no tuning and after tuning its steady @ 950 and hasnt stalled once in any foward gears...when i make the quick change to reverse its stalled twice in about a month now so not bad
have fun
Bill
have fun
Bill
You will have to drill the throttle body hole larger to help the surging and also dynotune with wideband is a must. Don't go to large on the hole. Your probably running rich as hell now.
I would crack the throttle blade open a bit and adjust the main ve table with edit from 400 800 1200 rpm column down 20%. The mixture is probably rich and causing the surging. Don't drill unless you have too. Work on the tuning first.
TECH Enthusiast
Joined: Dec 2001
Posts: 601
Likes: 0
From: Texas
No need to drill the TB....
1st time my H/C and TC were installed and tuned via LS1edit the car would surge like hell and die at every light - hell it would even die moving down the road if I tapped my gas or tapped my brakes too quick. I took it back to the tuner the next day and it turned out to be the IAC, car now idles like a rock at 800 when warm.
Im running Absolute Speed heads and a TR224 563.563 cam.
Good luck
1st time my H/C and TC were installed and tuned via LS1edit the car would surge like hell and die at every light - hell it would even die moving down the road if I tapped my gas or tapped my brakes too quick. I took it back to the tuner the next day and it turned out to be the IAC, car now idles like a rock at 800 when warm.
Im running Absolute Speed heads and a TR224 563.563 cam.
Good luck
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Thanks for all of the replies guys. It may very well be the IAC. I sent the throttle body to Jantzer to get ported. I took the TPS and IAC off before I sent it. It came back with both pieces in place. I'm going to try to using my origonal IAC.
As far as the tuning goes I have a Predator from James. He made me a custom tune to start the motor and I did some A-tapping. It was very lean straight across the board. So I sent that info to James and he touched up the tune and according to A-tap LTFTs are 0.00 to -4.7 under all cruise conditions at various speeds and LTFTs at idle are 0.00. WOT O2s are .875 and .900 avg.
As far as the tuning goes I have a Predator from James. He made me a custom tune to start the motor and I did some A-tapping. It was very lean straight across the board. So I sent that info to James and he touched up the tune and according to A-tap LTFTs are 0.00 to -4.7 under all cruise conditions at various speeds and LTFTs at idle are 0.00. WOT O2s are .875 and .900 avg.
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On The Tree
Joined: Dec 2003
Posts: 179
Likes: 0
From: Bloomington, MN
if you have a scanner or access to one what you need to do is open the throttle blades [#15 torx] untill the iac counts are in range i have found 30 to 50 works well . what is happening now to you is your iac is wide open trying to let the required amount of air in to achieve your desired idle speed and it is not enough.by opening the blade further it allows the iac to move in and out to regulate the desired air needed for idle.
Originally Posted by triumphman
if you have a scanner or access to one what you need to do is open the throttle blades [#15 torx] untill the iac counts are in range i have found 30 to 50 works well . what is happening now to you is your iac is wide open trying to let the required amount of air in to achieve your desired idle speed and it is not enough.by opening the blade further it allows the iac to move in and out to regulate the desired air needed for idle.
