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
Thread Starter
Banned
Joined: Sep 2009
Posts: 213
Likes: 1
From: st louis, mo area
would a vacuum leak cause the idle problem only when coming to a stop? I think a leak would manifest itself at all times.
also, i can see the iac count going to 0 in the log. that's when it will try to die. a little heel and toe action on the throttle and it idles fine.
also, i can see the iac count going to 0 in the log. that's when it will try to die. a little heel and toe action on the throttle and it idles fine.
Thread Starter
Banned
Joined: Sep 2009
Posts: 213
Likes: 1
From: st louis, mo area
Moe - there aren't that many idle tables...maybe 10. my tuning laptop is at home so I can't actually see the tune now but I did list the throttle follower iac vs mph in my first post.
do the offset tables add or subtract units listed in them?
do the offset tables add or subtract units listed in them?
Didnt notice, but dont worry so much about numbers, give the motor what it wants, I have had cars that would not idle correctly with the usual 30-40 count, but idled fine in the 50-60 range. either raise the steps a little or crack the TB open at very small incriments, like 1/4 turn, do only one thing at a time..
