Preparing to remove the lower hot-side cac tube/boot, I've noticed that the cac cooling fins on passenger side are oil covered on motor side of cac.

Is this typical, or traumatic ??

 

Is the CAC boot oily?? Does it have cracks in it. That could be the source. While the boot is off you could also pull the cold side and do a pressure test with an air hose on the cooler itself. I wouldn't put over 20 psi in it if it were me.

 

Lower CAC Boot exterior: 50% was covered with thin layer of oil/road grime.
Interior had small amount of dirty oil.

Cleaned and thoroughly checked for any crack/pin hole/wear mark/etc -- looks and feels good.

Put my original MAP sensor back on with a 3/16 hose (Tight) & did a short road test.

Truck runs fine - except for wot, then Limp Mode --- old issue.
DTC = 1, so PCM apparently won't let me "lay rubber".

 

WOT then limp mode sounds like a sticking turbo or vgt problem minus any other info.

 

I need more info on what triggers Limp Mode.

My suspicion is PCM insists on All parameters being in tolerance - or Limp Mode until problem / code cleared.

If that is correct - then any of 15 or so issues (to include sensors) could be the trigger.

 

Have you disco'd the batteries and done a re learn on the VGT? That helped my driveablity problems when I first got the truck

 

Yep, yesterday.

Result = P0603 Code (due to KAM) -- cleared code & continue guessing.

 

Perhaps using the official term "Limp Mode" is inappropriate.

Presently, for a few months now, truck will run just fine (to include towing a 16k 5th wheel trailer through the hills of TN) - Providing I do Not go WOT.

If so, it balks at 2900 rpm (4.0 Boost), will Not upshift, & puts out a slight amount of white smoke until I back off the accelerator & allow tranny to upshift. Then, eventually, turbo will spool up to around 20 = 80 mph w/power.

Don't know official term of this condition (Limp Di*k ??)

 

Limp mode will reduce your power to app. 35 mph and will not go any higher till you do a restart.

 

Thanks for clarification.