Idle Not Steady At All

[blazin_talon]

hey guyz. i ahve a 1g 93 talon with a 6-bolt cyclone. ive always had it set to idle at 1,100 rpm. just started having this problem recently. after my car warms up a bit, it wont idle steadily. it will hold at 1,100 then dropp to 1,000 and even 900 rpm, then back up to 1,100rpm. Now i noe it cant be the isc or any of those sensore because i have a microtech full stand-alone ecu and none of those are plugged. ive read other forums about idle surge and jumping to higher than normal rpms at idle. but my problem is diffrent. my rpms at idle decrease. please help

 

[Gstclipse69]

It could be a bad o2 sensor or mas. Have you checked for any vaccum or boost leaks?

 

[spawn7037]

I heard of this before in a couple other threads, happened to me too for about a week and then it went away, same with the others, how long has it been doing it?

 

[blazin_talon]

well it cant be the MAS cause i dont have one due to the standalone ECU. how do i check if the 02 sensor is bad?

i have checked for boostleaks and vacumm leaks didnt find anything. i look at my boost gauge and my vacumm is holding steady at 20

 

[Matt4g63]

boost leak test!!!

 

[blazin_talon]

like i said i already did a boost leak test. how do i check if the 02 sensor is bad?

 

[Gstclipse69]

Look at a logger and look at your o2 v at idle. At idle the readings should cycle meaning they should bounce around. When mine was bad it just said 0.00v or 0.001v all the time. Or if you have a air/fuel gauge look at it and make sure it bounces around (bout all they are good for)

 

[turboglenn]

Most surging or hunting idles are cause by a lean condition. If you're running an aftremarket ECU try richening up the idle. I run mine at about 12.5 - 13:1 and it stays perfect.. If i try adn get it to stoich (14.7:1) it's all over, almost stalling and jumping up and down. Check for leaks first and then see if richening it up doens't help a bit..also how much timing are you running at idle? Even the best aftermarket ECU's lack the expertise tuning of a mitsu factory engineer, and idle is the hardest thing i've ever tunes on any car, especially during weather changes and having big injectors to boot since they don't like opening for short time periods that they need to at idle.