APP Problem I THINK..

[Yngdmax92]

have a 2003 cc/sb duramax, 200,000 plus miles, built trans, turbo yadda yadda supporting mods, my truck has been having this problem lately that i can explain but i will try. When i press the throttle to increase throttle input the truck will rev up like normal, then die off and resort back to idle till about 20percent throttle. It drives me frican crazy, cant back up to trailers, cant take off easy, i am pretty sure it is making my transmission shift weird when at part throttle.

here's the video
http://s1284.photobucket.com/user/ridergonwild5692/media/VID_20140819_174508832_zps077cd0aa.mp4.html

 

[Yngdmax92]

any ideas or where to start looking would be great. Also no cel is on at all for anything of the sorts

 

[DAVe3283]

Woah, that is odd. Looks like the ECU is seeing some throttle input.

Try and log the 3 APP voltages. 2 should go one way when you press the throttle, and the other should go opposite. If one of the 3 is not responding right, the ECU errs on the side of caution and won't actually apply the throttle, IIRC.

What it is doing does act like a bad throttle pedal. Can you snag a known good one out of a buddies truck to try?

 

[Yngdmax92]

have no idea on how to data log with my autocal, but i was driving my truck the other day and some codes popped up, p1125, p2122, p2138, p2133. does this mean its safe to say that i need a new pedal assembly?

 

[Yngdmax92]

Ttt

 

[Yngdmax92]

Just an update, tried a new throttle assembly and still exactly the same as before. I am going to check my wires, where do the wires run after they come though the fire wall on a lb7. Do they go straight to the ecm? Let me know

 

[Yngdmax92]

now getting a p2133 everytime i start the truck, does anybody know where else i should check the wiring? it states voltage is too high? really need some help here

 

[Yngdmax92]

Sent a email to kory to see if maybe the tuning is an issue, its getting worse and worse, my truck will not even fully go wide open any more but my scan tool still reads that it is seeing 100% app

 

[Yngdmax92]

ttt, i went though all the grounds, took them off and cleaned them, followed the wires for the app sensor, went into the big bundle of wires that goes to the fuse box. took the connectors apart and put electrical grease on them, both app sensor ones, the two big connectors over the drive side valve cover. but what is super interesting is i was messing around with it in park, watching my main injection command and something is indeed telling it to command zero pulse, then it reverts back to idle, like my rpms will literally dip down to 400rpms, then come back up to 600-650 at regular idle. Its throwing a p2133 code consistantly and wont go away now. Could someone point me in the right direction on how to figure out which circuit is circuit F on the truck. Its stating that it is getting to high of voltage

 

[Yngdmax92]

Does any body have any clue of the operating voltages of app sensor?

 

[DAVe3283]

The APP runs at 5 volts, but should not get 5V back out of the sensor.

There is a bulletin (View attachment #PIP3004.pdf) that says you might get the DTC P2133 if the wrong part number pedal is used. Read that, and verify the right part number was used.

Also, here is a diagnostic procedure: View attachment DTC P2133.pdf
That document has the voltages that should come out of all 3 sensors inside the APP. It also has a full diagnostic tree. If the harness is OK, then the next step, unfortunately, seems to be a new ECM. But run through that procedure and see where it gets you.

 

[Chevy1925]

Your not running a lock up box are you?

 

[Yngdmax92]

Okay, today again i checked the harness. I took out the ecm and inspected pins and pins on the connectors. then i did a continuity test on all the pins for the app sensor and all tested good...........now i am losing my mind. Next i moved to the pedal again and checked for correct source voltage and proved that all voltages are 5 volts ref. Now dont call me dumb or nothing because i didnt know at the time, but i grabbed a 5.3 pedal out of the junk yard that i work at. plugged it in and it didnt solve the problem but did create the cel to kick on for p2133. So reverted back to my stock pedal. the voltages that the snap on solus reading is app #1.76 volts app#2-4.25 volts app#3-4.00volts......this is all at rest. They do fluctuate properly it seems. Whats really really stumping me is that i can visually see that my ecm commands 0 pulse width on my edge cs when i am at 2-15 percent throttle and then reverts back to idle. It all happens in seconds



James- no i am not running a lock up box, i am using kory's new tcm 2nd gear lock tuning...btw is stinkin AWESOME

 

[Yngdmax92]

So me using the 5.3 gas pedal explains the high voltage, but it still did it with that cell and pedal and using my stock pedal. So i guess i am going to try a friends pedal that i know 100 percent that is good. Then if that doesnt solve the problem then i have no idea where to turn too.

 

[Yngdmax92]

Another update, going to try a friends 100 percent working properly app sensor, if it still glitches and acts weird i am going to down load a stock lb7 tune. If it still glitches after that i am going to locate a ecm that i could maybe borrow from some one and throw it on.

 

[Yngdmax92]

Update, okay guys i am 100 percent stumped, my pedal voltages are fine out, i have the orginal pedal in the truck and it works fine, the ecm reads what i am doing with my foot but having a glitch or something. should i just bite the bullet and try a ecm. Also idk much about tuning, but my truck commands 0 us main injections when i left off the throttle but commans 400-500 us idieling.... is that correct?

 

[Yngdmax92]

I even have a stock tune in my truck too boot. still no codes, no nothing.

 

[DAVe3283]

At this point your guess is as good as mine. When I get stumped, I go to the GM manuals (which I posted earlier).

The GM procedure makes it look like a new ECU is in order at this point. If you are near some other members, one of them might have a spare ECU you could swap in to test.

 

[Yngdmax92]

i have a p0089, and codes for glow plugs and intake air heater. The fuel pressure, it just kicks on when cold because i must have my raptor like 1 psi to high and when off the throttle rail pressure will start to rise ever so slightly and kick the code for it. Going to try a new ecm and report back

 

[Yngdmax92]

lol okay fellas, i just changed the ecm and it was no different. Still does the same exact thing. A guy on here was nice enough for me to pay shipping and try it and send it back. But any ways, could it be a bad ficm that is doing this?