Engine/Transmission (1998.5 - 2002) Anatomy of an APPS - the SEQUEL!

[timbo]

https://www.turbodieselregister.com...198522-anatomy-apps-sequel-3.html#post1918971

 

[Gary - K7GLD]

BUMP - for some of the later arrivals, experiencing their first APPS issues...

 

[Willys]

In doing the research for this improvement, have you found that the APPS is the reason for not only dead pedal but surging as well? I have a friend with a 24V who has spent several thousand throwing parts at trying to fix the surge issue with no luck(IP, APPS which helped for a while, injectors, MAP and engine speed sensor among others... ).

We're trying to find a culprit without throwing to much more money at the truck, just curious about the APPS and surging, but I don't want to take this thread off topic... .

 

[rubberneck]

Man i love this place, ive been of pursuing other hobbies for the last year or so. Check in once in a while just to see whats up. Lately my APPS has been acting up (all the common symptoms) been nursing it along for the last 6 months. After a staggering quote from my local dealership, i logged on to review the past posts on the subject. I found out about timbos solution. Timbo, sent you a PM, im all in, send me an invoice and i will paypal ASAP. This is awesome. Anytime i can avoid spending money at the local dealership is a positive to me, i hate them. Plus it sounds like a better quality product for 1/5 the money. cool. Once again the TDR membership pays off in spades

 

[Cliffman]

My "check engine" light came on and scanner reads "PO122 Throttle/pedal Position Sensor A Circuit Low Input". Cleared the code and it keeps coming back on first start. Truck runs perfect! Removed the APPS, checked connection and all looks good. Why does it keep throwing codes if the truck runs good? I don't get it

 

[PC12Driver]

My "check engine" light came on and scanner reads "PO122 Throttle/pedal Position Sensor A Circuit Low Input". Cleared the coad and it keeps coming back on first start. Truck runs perfect! Removed the APPS, checked connection and all looks good. Why does it keep throwing codes if the truck runs good? I don't get it

Could be the APPS getting noisy. If the variable signal from the APPS has less voltage at idle than it did when the ECM last "learned" the APPS, you'll get this code. The ECM will automatically learn the new voltage for idle, and you won't notice anything except the CEL and code.



Incidentally, if the voltage is higher than what it learned at idle you'll just end up with a higher than normal idle and no code. Again, the ECM will re-learn the new voltage and idle should be normal after a key cycle or two.



Before spending money I'd check all the ground paths from the ECM to the battery though, just in case.

 

[Cliffman]

Before spending money I'd check all the ground paths from the ECM to the battery though, just in case.

Hmmm, how does one go about doing that? How many ground wires are there coming from the ECM and how do you trace it when it's all raped up in loom and tape?



Thanks in advance...

 

[Cliffman]

Okay, Put a Snap-On Scanner and it's reading 0 voltage on start up only. Right after start up it goes to normal voltage. Is this the APPS going south or something else causing low voltage at startup.

 

[jraker]

Could be the APPS getting noisy. If the variable signal from the APPS has less voltage at idle than it did when the ECM last "learned" the APPS, you'll get this code. The ECM will automatically learn the new voltage for idle, and you won't notice anything except the CEL and code.



Incidentally, if the voltage is higher than what it learned at idle you'll just end up with a higher than normal idle and no code. Again, the ECM will re-learn the new voltage and idle should be normal after a key cycle or two.



Before spending money I'd check all the ground paths from the ECM to the battery though, just in case.

I am confused. I am getting the P0122 code and the companion code, but I don't have a CEL. Is this because the Banks is blocking it? Truck is really surging and feels like it is missing a little. Fuel pressure stays at 14.

 

[PC12Driver]

I am confused. I am getting the P0122 code and the companion code, but I don't have a CEL. Is this because the Banks is blocking it? Truck is really surging and feels like it is missing a little. Fuel pressure stays at 14.

I don't think the Banks box is smart enough to block the CEL. I've had a few codes set in the past without the CEL showing up. I'm thinking it's a glitch in the Dodge software. If the 0122 is there, you probably have a bad APPS.

 

[EthanWhite]

Question

BUMP - for some of the later arrivals, experiencing their first APPS issues...

Gary, could a failing apps cause a misfire when at operating temp? Also my cruise acts funny- it you set it, it will gain like 7mph then slowly slow back down to the set speed. I have been told the misfire is either a bad injector(s) or a failing VP-44. I have plenty of fuel pressure (fass ddrp) and have a Powermax TST. I removed the TST but it still misses, also it missed when I had my edge on it. Thanks in advance.

 

[Gary - K7GLD]

Prior to my own VP-44 failure, I had the misfire experience, but only a couple of times, as well as erratic throttle control - but no CC problems. Overall, I've had few issues with my truck other than the VP-44 - so not real qualified to offer advice - the stuff I've provided here on APPS substitution are mainly related to the alternative devices seen and described here, because normal replacements are so expensive and have a habit of failing prematurely - in my case, mine had operated perfectly, until I built my own $10 substitute seen at the start of this thread - that one is STILL installed and working perfectly - the OEM is now my spare!

 

[Gary - K7GLD]

HEY guys - nearly 2 years, 20K miles on this version - and my $10 APPS is still going strong!

 

[rweis]

Yeah, my microswitch is purring along as well. I don't put as much mileage on her as I use to, but zero issues in over 2 years. Who would have thought a microswitch was all that the APPS circuit was. Let's see, a 1,000,000 cycle microswitch - 200 starts (probably say 10,000 cycles of the microswitch) = 980,000 cycles to go @ 10,000 cycles / year is only 98 more years before I have to buy another $3. 50 microswitch (I'll be 161 years old). I think that qualifies as a PERMANENT fix.



Bob Weis

 

[benhall]

I have approx 20k on mine as well, and no issues.

 

[Gary - K7GLD]

Yeah, my microswitch is purring along as well. I don't put as much mileage on her as I use to, but zero issues in over 2 years. Who would have thought a microswitch was all that the APPS circuit was. Let's see, a 1,000,000 cycle microswitch - 200 starts (probably say 10,000 cycles of the microswitch) = 980,000 cycles to go @ 10,000 cycles / year is only 98 more years before I have to buy another $3. 50 microswitch (I'll be 161 years old). I think that qualifies as a PERMANENT fix.



Bob Weis

Hey Bob - don't see as much of you here as we used to!



As to my particular APPS - this version was purely a test to see how long that in-line $1. 50 slider potentiometer would last - can't seem to wear the dern thing out, and I still have another backup pot I got as a backup! I still have my OEM APPS assembly, converted over to the microswitch, even though it was all working perfectly before we all got on this "Frankenstein APPS" bit! It's now my spare.

 

[TFarrell]

here is a question i was wondering if any of you guys could answer. i have a 98 2500 auto. i just put the timbo apps on and had the trans rebuilt about a month ago. my question is now all of the sudden i was having problems with the torque converter going in and out of lock. the trans guy says this is becasue the apps signal voltage is moving around alot as read by his snapon computer. but if you take a meter to the signal wire at the apps it holds a steady voltage. so im guessing somewhere between the apps and ecm the signal is getting noisy. does this sound right? also the other day i disconnected the batterys and reconnected them to reset the ecm and now it locks great. i stopped by the trans shop so he could plug it in again and he says the voltage is still jumping around even though for now everything is working fine. what do you guys think?

 

[BarryG]

You may want to look at a noise filter for the trans line/wire. DTT sells one and am sure others do as well. Seems like a noisy trans line/wire is a relatively common issue. Would be worth a call they are very helpful.



DTT Performance Diesel Transmission and Power Accessories

 

[Gary - K7GLD]

You may want to look at a noise filter for the trans line/wire. DTT sells one and am sure others do as well. Seems like a noisy trans line/wire is a relatively common issue. Would be worth a call they are very helpful.



DTT Performance Diesel Transmission and Power Accessories

YUP - what he said! ^^^^^^^



A common problem, regardless of APPS in use at the time...

 

[rweis]

Had same same here, DTT noise filter fixed it fine. That was uhhhh 4 or 5 years ago.



Bob Weis