Cold Idle Control issues.

[Power Hungry]

Originally Posted by 907dave

Yeah, seems to be working fine, no noise (AC volts) in the charging system either.

Since posting this I had gone through all my battery/ alt connections and cleaned everything, regardless of how it looked.

Since then it has seemed to be working normally.

There must be an undefined table that has some bearing on this...............ohhh Bill!!!!

I'm looking into this. There's only one problem. I'm having a little trouble generating the -40º temps out here.

The issue definitely seems related to your IAT as this has significant bearing on the Cold Idle control. Case in point... I was in a truck on a roughly 15º day and the engine was sufficiently warm because I was inside tuning it. After a short bit, the idle ramped up even though EOT was well over 100º. This indicates that the idle strategy does look at IAT as well as EOT to control high idle.

Now the big question is, where does this function go awry? Is the PCM actually miscalculating the IAT output or is the scan-tool miscalculating the PID data and handling it as an unsigned value instead of a signed value? These are question I don't yet have an answer to since my truck is in GA and I'm in FL, but I will certainly be happy to investigate this and see what's up.

Stick around...