Tree DR

Just wondered what happend inside it.

dkenny

most likely..
contact issues..
or electrical noise kills the transistors inside

Tree DR

If it killed the transistors why would the dead peddle be intermitent?

pind

if you break down the apps, you'll see two filaments in there. The apps is basically a potentiometer. ( variable resistor ) what happens is the ribbons get "flat" spots in them, which occcur at the most frequently used settings.

For me, its at cruising speed on the highway. After a couple years, on comes the dead zone. You can do a hard reset and buy some time, but you'll end up changing it anyway.

Tree DR

Mine first did it about 8mo ago at 55-60mph 3 times one day. Never reset it. Now it did it at 40-50mph 4 times. Haven't driven it since so don't know if its going to do it again. If it was a flat spot why did it not continue to do it? And why is it doing it at a differen't speed now?
Makes me think its a contact issue. Or an electrical problem somewhere else messing with it. My exhaust brake quit working about 5min before the APPS started acting up. Exhaust brake started working again after I shut truck off, and APPS didn't do it again after shut off either. Makes me think its a computer problem cause by a short somewhere.

pind

it is an electrical problem, caused by a bad contact within the apps. Hence the flat spots that I described. Many times, if you sit with the truck in neutral, running, and carefully play with the throttle pedal, you can make it throw a 0121 or 0122 code. You'll know it when the check engine light comes on.

Try it out for fun

Tree DR

I calibrated the APPS. The white sticker on APPS said .551 and when I check it at the PCM it was .448 so while I had the volt meter hooked at the PCM I adjusted the APPS to .551. As I tightened the APPS it change to .549. Figured it was close enough. I did recheck it at the APPS and it read .552. So far in 35mi it hasn't dead pedled again. Also while I had the APPS off the truck I sprayed it down with some electrical connector cleaner. Not much of an opening to spray it in but anyway.

Tree DR

Update, 600+ mi and not problems. Done 100+ of that in town with and without 4k trailer. Ive got the new APPS incase I need it.

gsbrockman

I had some "dead pedal issues" on my 1999 RAM 2500 Quad Cab.

I tried this :

https://www.dieseltruckresource.com/...n&onlynewfaq=1

.....and all seems to be well. I guess I'll for sure know on my next hauling job. It sure did seem like a heck of an improvement on my short 5 mile test drive just a few minutes ago.

TOM R

when I had mine apart i noticed that the hole in the bracket where the throttle shaft goes through to the sensor was egged out quite a bit

Tree DR

I did reset the APPS after I calibrated it. I think my idle is a little higher. I haven't had an opertunity to check fuel mileage yet. I had adjusted the valves about a week before and got 20.4 with normal gear and 20.1mpg with 17ft canoe on top, was 19.6-8 at 75mph might get a chance this weekend to check mpg. After I calibrated and reset APPS power is better at 14-1700rpms in particular.

Tree DR

mpg has improved. Mixed driveing 800+mi, (200mi city 100 with trailer, 600hwy, 200loaded heavy with wood, 75mph) 22mpg. Still have new APPS in box. This is my 10th dodge diesel and I never got above 18mpg on any of them so this high mpg stuff used to be unbelieveable to me but this is my first 3/4ton.