Ok here's what I got, it runs good everything seems to be in the ballpark but no matter what I set the IAC steps to it won't go below 49. I set the target idle everywhere from 1 to 650 it still idles at 850. Yes, I have checked for vacuum leaks. Is there somewhere in tuner cat I can go to and change this? I am lost, can anybody help Grumpy, Glenn, Jon?

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Chronologically challenged. But still kicking!
'92 CAMARO RS
305 TBI 5/spd (now TPI)
B4C Alt.
'69 camaro-BB/Lenco,1050 dominators, /Pump Gas/no drugs 8.97-150+/3200lbs.
SoCal Thirdgen F-Bodies

 

I'm not sure if there is an Idle Speed IAC Steps vs. Coolent in that code or not. I know the 8D mask has it(Glenn defined it). I'm not sure if there is a hac available for your ecm or not. May be something to look into.

Brendan

 

What thermostat are you using? Some won't kick the idle down until coolant reaches a certain temp.

 

Key on
jumper A-B on the ALDL
wait a full minute
unplug IAC
key off
undo A-B jumper.
What is the idle speed?.

You have to match the mechanical setting to the commanded value, within reason. Ecm gets too confusing of steps/speed it will go into a fail soft mode. Even anti-stall.

Some one needs to sit down, and write out a hac on this ecm, it's about the same as a Mask 42, just the rom is moved around sections of the code should lift from one to another.

 

I did that procedure and set the idle to 600 RPMs, with the IAC disconnected. It idles fine there. As soon as I reconnect the plug, the idle jumps to 850-900.

There is a hack file for the 8746, it was posted last week by JPrevost in the TBI board. I'm not versed enough to know how to read it. Can you help me find the idle rpms in there?

My target idle is 650, and it idles about 750 in open loop. But it jumps to 900 as soon as it goes into closed loop. It idles at 38-40 KPa at 127-129 INT and 125-127 BLM. There is also a maximum hot idle speed I set at 700, but it has no effect.

Thanks for the help,
Don >>>

 

Well it hurts to admit to being a dumb *** but.....I located the problem. You guys were on the right track about the stallsafe mode.
The switch on the power steering was the culprit. I unhooked it and the IAC went down to 6 steps and the idle dropped.

Oh well, as we live and learn.
Thanks guys for taking the time to help!
Don>>>

------------------
Chronologically challenged. But still kicking!
'92 CAMARO RS
305 TBI 5/spd (now TPI)
B4C Alt.
'69 camaro-BB/Lenco,1050 dominators, /Pump Gas/no drugs 8.97-150+/3200lbs.
SoCal Thirdgen F-Bodies

 

Glad you figured it out before I got to read the post! Saved me some research time .
Grumpy, you want to write up a good description on the hack for the 8746? I have the hack and I've edited my tunercat definition file BUT the hack is near 80 pages and I'm still a student working full time (no free time).

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, Jon (350 TBI!)
91 Red My website

 

Once I solved that little problem, I burned a few more chips to fine tune it and now it runs super and kicks butt. I can highly recommend this combo, it works.
I used the stock TBI intake and bored it out to 2" a 454 t/b, ZZ4 cam, Sportsman II heads (pocket ported),68# inj., 1 3/4 headers, 3" Ex., and MSD 6a ign.(just because I had it).

------------------
Chronologically challenged. But still kicking!
'92 CAMARO RS
305 TBI 5/spd (now TPI)
B4C Alt.
'69 camaro-BB/Lenco,1050 dominators, /Pump Gas/no drugs 8.97-150+/3200lbs.
SoCal Thirdgen F-Bodies

[This message has been edited by Dyno Don (edited August 06, 2001).]