need suggestions for tune problem
Thread Starter
Banned
Joined: Sep 2009
Posts: 213
Likes: 1
From: st louis, mo area
need suggestions for tune problem 96 lt1 t56 AI heads/cam. Using JET DST to tune with.
I have a problem with the IAC value going to zero coming to a stop. Of course at that point I'm still rolling, maybe 5-10 mph, and it wants to die. So what I have to do is heel and toe the throttle with the brake foot to keep it from dying. Usually a couple of quick stabs at the throttle and it'll idle fine at that stop. Then at the next stop the same thing. This is the only idle drivability issue I have.
Normally idles at 40 counts and has idled fine coming to a stop in the past. new iac unit in oct of last yr.
I can't figure out what needs to be changed in the idle constants and tables.
throttle follower iac vs mph
mph steps
0 30
4 30
8 30
12 30
16 30
20 1
24 1
28 5
32 5
36 5
40 5
44 5
48 5
52 5
56 5
60 5
64 5
tps iac offset vs rpm
this table is all zeros
I have a problem with the IAC value going to zero coming to a stop. Of course at that point I'm still rolling, maybe 5-10 mph, and it wants to die. So what I have to do is heel and toe the throttle with the brake foot to keep it from dying. Usually a couple of quick stabs at the throttle and it'll idle fine at that stop. Then at the next stop the same thing. This is the only idle drivability issue I have.
Normally idles at 40 counts and has idled fine coming to a stop in the past. new iac unit in oct of last yr.
I can't figure out what needs to be changed in the idle constants and tables.
throttle follower iac vs mph
mph steps
0 30
4 30
8 30
12 30
16 30
20 1
24 1
28 5
32 5
36 5
40 5
44 5
48 5
52 5
56 5
60 5
64 5
tps iac offset vs rpm
this table is all zeros
Teching In
Joined: Feb 2007
Posts: 34
Likes: 0
From: Charleston, SC
Sounds like a vacuum leak, to me. If it was fine with the old IAC, then something else is wrong. I wouldn't try to tune it out. I would have suspected too much base idle setting on the TB until you mentioned what it was doing before.
That table above is a throttle follower type of table. It adds iac air as you open the throttle to give you a softer idle decay on decel.
Why did you replace the IAC?
That table above is a throttle follower type of table. It adds iac air as you open the throttle to give you a softer idle decay on decel.
Why did you replace the IAC?
