LT1, OBD1, M6, high idle issue

[prorac1]

I know this is an old problem with 6 speed LT1 cars, but I have yet to find anybody that has an answer. Bolt on car. Idles fine while stopped. When driving down the road, and you push in the clutch, it idles around 1500-1700 rpm. Once you come to a complete stop the idle will eventually settle down to a normal 800 rpm. No vacuum leaks, and the IAC settings are all stock in the pcm. Any ideas on what this age old problem could be, lol. Thanks in advance, Eric L

[98blackbeauty]

never noticed mine doing that!

[1BADAIR]

needs tuned.
throttle follower and base idle airflow needs to be adjusted

[Phantom409]

needs tuned.
throttle follower and base idle airflow needs to be adjusted

Yup!

Eric, mine does the same thing
Come to a stop and she idles at 1500 unless I give the gas a tap.
Check with TJ at Baker Eng. 616-837-8975
Tell him Kyle sent ya

[prorac1]

I dont have a table in my tunercat for base idle airflow. What I cant figure out is that it will come down by its self when the speed sensor reads 0. All of the iac functions in the program are stock, the heads, cam, throttle body, intake, maf, are all stock as well. Mods are in sig. I wouldnt think that any of my mods would be causing idle problems? I have heard of people zeroing out the throttle follower tables and helping it, or i guess it could be a bad iac. Im going out now to do the shoebox test on the iac contacts and reset the iac, ill let ya know what i find. Thanks for all the input. Eric L

[1BADAIR]

are 1.6 rockers stock? anything that improves the VE of the engine will affect it

[prorac1]

True Larry, guess i never thought about it from a VE stand point. Well, I fixed the problem. Reset the IAC position acording to shoeboxes website, checked the voltage on the plug (it was good), checked the tps voltage, and all was fine. Took it for a drive and did a datalog and all is good now. But, i have some other issues now, lol. Who can read datamaster datalogs? Im trying to figure out my LT and ST fuel trims. What does the red and green mean? which one is rich and which one is lean? Also, with my minimum amount of mods, my stock (24lb) injector duty cycle is 86%. Is this to high? And im getting a small ammount of knock retard at higher rpms. It seems the stock timing around 40-60 kpa of map is around 40-42 degrees and it keeps pulling 3 or 4 degrees out around 4000-5000 rpm. I would think that I could run more timing than stock with my mods and increased VE? Im going to try to pull a couple of degrees out in that area and see what happens. Any suggestions are appreciated. Thanks guys, Eric L

[1BADAIR]

not sure about lt1's but ls1 like 28-30 degrees of timing

[steve40]

green is lean, red is rich

at what condition are you seeing 86% duty cycle, usually 80% is a rule of thumb, but you can push it farther, not like your wot for miles at a time.

[prorac1]

Towards the top of the rpm band it hits the mid 80s for dutycycle. So I dont think its anything to worry about. My afgs peaks at around 270 which seems normal. Anybody have a way to look at my datamaster file and check my lt and st fuel trims, im not real familiar with working with those. Thanks Eric L

[steve40]

Towards the top of the rpm band it hits the mid 80s for dutycycle. So I dont think its anything to worry about. My afgs peaks at around 270 which seems normal. Anybody have a way to look at my datamaster file and check my lt and st fuel trims, im not real familiar with working with those. Thanks Eric L

you're fine, i think i got up to 100 or very close to it. you can send it to me...been a while since i've used it....the lt1 left 2 years ago for me, but still familiar with them

[prorac1]

What is your email address? Thanks Eric L

[steve40]

whoops...forgot to post that

steve_davidson14@hotmail.com

can email or msn it

[prorac1]

data log sent, thanks again, Eric L

[meissen]

Shoot it over to me if ya want too - I'm no expert on reading the logs but I can compare it to mine.