Engine/Transmission (1998.5 - 2002) Autopsy of an APPS

[Sticks]

Originally posted by Bob4x4

Not JUST a rheostat . It also has idle validation switches



Bob

LOOK! Somebody that knows something!



What is the idle validation thingy, and what does it do?



Can we get around it?

 

[Bob4x4]

2 idle switches,one on at idle,and off above idle and the other works in reverse. If the two switches disagree a code is set.



Bob

 

[Gary - K7GLD]

These dern controls were DESIGNED by humans, MANUFACTURED by humans, and ASSEMBLED (maybe!) by humans - and I'll guarantee ya they CAN be taken apart, repaired, and REassembled - it's simply a matter of finding the best way to do it!



I'd love to have a couple to work on. but suppose the dealers keep the repaired ones...

 

[Sticks]

Gary, your best bet is going to be a victimized TDR member who0 had to replace the sensor out of pocket.



Do what I did, post a wanted ad in the classifieds - just pay shipping.

 

[Gary - K7GLD]

Good idea - I'll try here first with the same offer - anyone with a failed APPS, contact me, I'd like to experiment on mechanical troubleshooting, repair, and returning one to service - and like Sticks said, would gladly pay shipping, Of course, would post detailed findings and photos as I have done in similar efforts with liift pumps and pushers... This won't work unless I can get 2 or 3 units - one to screw up, and 1 or 2 to actually fix... Contact me by PM if you like...



BUT, if one has failed due to electronic issues, probably dead in the water, not properly set up for that type of repair/replacement...

 

[Texas Diesel]

How many do you want? Do you want the whole APPS or the little black doo-dad? I have access to 10 or so bad APPS assemblies. PM me.

 

[Sticks]

Originally posted by Tejas Deezul

How many do you want? Do you want the whole APPS or the little black doo-dad? I have access to 10 or so bad APPS assemblies. PM me.

Tejas Deezul - you have a PM request for 4 or 5 of them.

 

[Texas Diesel]

No problem, will be a week before I have time to go get them.



I'll split them between you and Gary.

 

[Forrest Nearing]

why not just adapt a TPS off of another vehicle? that thing looks a lot like a Ford TPS sensor that are dime-a-dozen... just need to do some resistance measuring to find one that'll work... there'll need to be some modification of course, but not much by the looks of it.



the biggest thing is getting a good unit to get the closed throttle and open throttle voltage readings so that you can set the new sensor to the same setting.



this is a VERY common thing in the Ford realm... setting TPS voltage when installing a new one.



Forrest

 

[Gary - K7GLD]

Forrest, I suspect there are a unique set of operating values proprietary to the Dodge APPS that mate it to the ECM - be pretty coincidental if those values happened to be the same as Ford or any others...

 

[KOREDISH]

Apps Codes and symptoms

I would like to find out what codes the trucks are throwing and what symptoms their having. I've had a P0237, which I know is for the MAP. I replaced map, I'm still getting the code. The light comes on and go off periodically and I get poor throttle response occassionally. i. e. I can put half way to floor and truck doesn't move for a while.



Dish

 

[24VChev]

I was looking at a Freightliner with a 24V cummins in it. It has the pedal position sensor under the dash. I did not count the wires but maybe a sensor from a Freightliner may work.



I work on a lot of electronic Cat engines. Their pedal position sensor works the same way also. I will look into it.



I also have a pedal position sensor from the GM electronic 6. 5 it may be usable also.



Malcolm.

 

[Sticks]

Heh heh heh... TDR think tank on a roll!

DC BEWARE, WE WILL FIND A WAY AROUND YOUR LITTLE CAPTIVE MARKET PLOY!





KOREDISH - I would check you MAP sensor connections. If you have a box connected up to it, that may be where the problem is. Unusual for a sensor to be bad when brand new, but possible.



The APPS sensor does not necessarily cause low power, more like erratic throttle response, or the engine acts like it has a mind of it's own and will spontaneously jump 50 to 250 RPM for a couple of seconds when the throttle is held in a constant position.

 

[Texas Diesel]

As soon as I get my truck back (body shop :{ ) I'll run get the APPS'.



THERE HAS TO BE ANOTHER SOURCE FOR THEM LITTLE DOO-DADS.

 

[PCrable]

If anyone needs another non-functioning APPS, I kept the old one that I had to replace from my truck.



I had thought that maybe one these days I would cut into it like Sticks did and figure out how they work... after seeing all the electronics in it, probably good that I didn't.



--Phil

 

[Gary - K7GLD]

For Sticks - or any others contemplating taking something like the APPS apart, here's what I would suggest for use with a Dremel type drive motor:



#ad




This little cut-off wheel is very thin - I use it to disassemble stuff like sealed Nicad battery packs and such. Hobby shops and better equipped hardware stores are a good source...

 

[Sticks]

I've got both those and the larger size. They do not work too well for cutting circles/curves in deep material. The next victim is going to be cut around the outside edge.



Gary, Let me know if you want some measurements (thickness, depth, where the ribbon cable is at... )

 

[Gary - K7GLD]

I'll gladly take all the helpful info you can give - no need to totally start over again if we have some preliminary measurements to start out with...



I'm sorta hoping to come up with 2 solutions, IF the finger issue is NOT a common one - I'm hoping to find the best physical location to drill the case for a shot of control cleaner for those only needing that to clear up dirty/intermittant problems with contact between the fingers and the carbon path - and then of course, seeking decent fix for badly worn carbon material...



As far as cutting goes. I'm hoping that what I pictured would allow a clean cut at the factory assembly seam...

 

[WOT]

The problem with these things is that they put moving parts that wear out with electronics that would likely last the life of the vehicle. Another problem I see is why the crap would you mount it on the engine if you didn't really need to? Wouldn't it be smarter to have it mounted to something that didn't vibrate constantly?



If you look at the pictures from the circuit board side you see the leads that go to the runs that the brushes ride on. If someone took apart JUST the circuit board side and then tapped into the leads that go to the potentiometer side and got the resistance value @ idle position and @ WOT then perhaps a substitue could be found. Then one could reuse the electronics part and run some wires to a new potentiometer that could be mounted on the throttle cable pivot.



I would also like to figure out the best place to drill a couple of holes on the potentiometer side so that you could squirt some contact cleaner in it and then blow it out to dry it. Maybe corrosion is really the killer.



WOT

 

[Sticks]

Originally posted by WOT

I would also like to figure out the best place to drill a couple of holes on the potentiometer side so that you could squirt some contact cleaner in it and then blow it out to dry it. Maybe corrosion is really the killer.



WOT

I think that it is more buildup of removed material on the contact surface that corrosion. This is a well sealed unit, I dare say air tight.



Gary - I will clean up my cuts tomorrow, and get some measurements and a map thereof. They will be either decimal inches, or metric (probably metric, as those numbers are easier to deal with than fractions).