So I should have probably posted here prior to changing my apps. My 2003 has developed an issue that I'm not sure how to diagnose from here. The truck runs and drives normally up to around 2000 rpm but then if I want wot the engine loses all power with smoke out the back and what sounds like a backfire or popping from the exhaust. I initially dug in and changed the apps after getting the codes 2121, and 2122 to the modded apps with the pigtail that I picked up from PDR Diesel Performance in Langley BC. Had to do a little bit of fiddling before it would work, but it didn't solve my problem. I do a fair bit of work on my own stuff but this is a little out of my experience zone and could use a bit of help on a plan of attack before spending more just for fun.
The truck has 335,000K and has the in tank conversion. Except for that and the Trans it has been pretty reliable since I bought it used in '06 with 85,000K.
Wondering if anyone has experienced this or something similar?

 

Any codes? What are your fuel and boost pressures?

 

Cel still on and showing 2122, 2127, 837 and 700. don't have any guages on the truck so will have to locate a test rig to confirm pressures.

 

Looks like you might be having problems with your APPS or throttle position sensor. Thats codes 2122 and 2127. The other codes are for your four wheel drive.

 

Did you calibrate the APPS after installation using a VOM?

 

Yes, followed the calibration instructions to adjust idle stop screw 'til voltage rise then back off 1/2 turn and then slowly depress and release floor pedal(some inst say once some say 3 times?).
Initially had no response at accellerator pedal on 1st startup but then at engine end handling harness and working throttle by hand it began to function but once truck was shut off and left for a few it would not work again.
Took off apps again to check continuity of pigtail, confirmed connections, reinstalled and calibrated again. 2nd time the voltage seemed lower but had also changed the battery in the VOM so....
Anyway 2nd time on initial start up, Dead pedal. Go to engine and fondle wiring, work throttle 2-3 times and it chatches, begins to function. Shut down and restart 8-10 times works fine. Go inside grab my gear to go for a test drive lock up house, start truck and get the dead pedal.
By now I'm a little frustrated and so I back off the idle screw 2-3 full turns, work the throttle 2-3 times and think I notice some idle drop and apps begins to function. I shut it down and leave it for a while and when I start it again no pedal. I work the pedal 3 times and it chatches and away we go to get fuel. After fillup same story, have to work the throttle to get the apps to actually work but since then it has worked without the jiggery pokery for 3 days now.
I know I need to recalibrate it again to get rid of the codes since I changed it after the last calibration but wanted to be sure it is functioning at all before I change anything else.
And that brings me back to my original problem with the engine cutting out at the 2000rpm mark under load. This has been happening for at least the last 3 months and I was thinking it was getting progressively worse so based on the codes and reading on forums I went ahead with the apps replacement.
There appears to be no change to that original condition, truck runs and drives normally until lead fills my foot.
Thanks for all help.

 

Another thing, the cutout seems to occur only after reaching full operating temp.

 

Going out on a limb here but are you running the original injectors?

 

Yes injectors are original