Another_User

Ok, how do you fix your cold start idle surging. You need to start you car during as cold an outside temp as possible, and your coolant needs to be completely cool too. You need to log Engine Coolant Temperature (ECT), Long Term Idle Trims (LTITs), and Short Term Idle Trims (STITs). Start logging with the key turned, but not on yet. Start your car. Let your car fully warm up. This may take some driving, and you may need to raise your fan temps back to stock temporarily if you reduced them. Your main focus will be on the actual temps your car operated in. After you are done logging, you will need to add your LTITs and STITs together. I haven't seen it, but it is very likely your STITs could go negative while your LTITs are positive, in which case you would subtract them or vice-versa. Use basic math...LOL. Do this at each ECT that appears in your Base Running Airflow vs. ECT table. Take the number you get and add (or subtract as appropriate) this number from the value in the table. You may want to add .1 or so just to make sure it is a hair high, but don't go crazy. The further your trims deviate from the Base Running Airflow table, the crazier your idle will be. Another note; there is an ECT value for enabling Idle Adjustment (I forget what it is actually called, but it is right there in the Idle tables). I am pretty sure that if you have a low temp thermostat this will put your temperature for your LTITs to adjust outside of where it will normally hit. So your LTITs won't learn. So you may notice you don't have any LTITs, like I noticed on mine. If your trims need to learn, this prevents it and when you restart your car it starts all over again with 0 STITs. Make sure your idle is pretty much stabilized at the ECT you use the LTITs and STITs from.

txhorns281

iTrader: (12)

do these LTITs and STITs still update even in open loop?

Another_User

The STITs always update. It's not an open or closed loop thing. The LTITs have that ECT before they start to update, and they update very slowly. Much more slowly than the STITs.