Another Idle surge post with microsquirt

[stevedemo]

I have a 86 GT, 5spd. Engine is a 5.0(302) with gt40 heads and intake. e303 cam and shorty headers with catless xpipe. I am running microsquirt from efisource and an aem xseries wideband. Engine starts and runs great up to operating temp. I have an electric fan that's controlled by the ecu and works great. Maintains 195 degrees without error. The engine will idle around 1000 rpms and when it starts to idle down it starts surging and will swing from 300 rpm to 1500 rpm and will eventually stall. Ive tried messing with timing and fuel tables. Ive messed with iac frequency and other misc settings and can not for the life of me find the issue. Ive attached the tune file. Thanks in advance.

 

[taco]

I will share what works for ME. Some may say this is cheating or wrong but it works great for me and my car.

I use table switching and have a fuel table to idle on and a table to drive on. I found that leaning the idle out helped the idle surging.

 

[a91what]

I have a set of videos you can use to help get the idle dialed in, they are linked in my signature

 

[stevedemo]

Its been a busy week. So what I found was with timing. The engine really likes timing. I'm new to tuning so wasn't sure how much to put in at idle. I've added 15 degrees across the board and idle is stable. I need to do more tuning but how do you know if your adding too much timing? Thanks for the help!!!

 

[a91what]

If your running 30+ at idle that's excessive... however cant argue with what works.

 

[Sparky714]

Watch Steve's videos and take his advise, he's a big help. I also got some great info from this guy. Watch these two videos.
View: https://www.youtube.com/watch?v=NN8SEaau1dw
,
View: https://www.youtube.com/watch?v=eF_uAxpbzCw
. Get the car to idle smoothly in open loop before attempting closed loop control. It will save you a lot of headaches.