Ok Gang...

I just had a wonderful phone conversation with Rburks this morning and his chasing his problems with his idle well he happen to mention the fact he did the APPS voltage adjustment and I like "OMG not again!" There is a article on the Internet that is wrote up wrong and need to be corrected and stopped.

Problem #1 - Voltage on label

Everyone is trying to hit this voltage dead on... DON'T! This is the voltage that the APPS sensor goes from ON idle start to OFF idle state. You voltage MUST be BELOW this number.

Like on mine the voltage is .519. Don't set the voltage at this set it below this mark say .480 to .490 because as you add in voltage gain or loss during normal operation of the truck it might cross the mark and go off idle and you end up with idle set at 950 to 1000. Then find out your exhaust brake, high idle and a few other things don't work!

STOP! Don't set the voltage to the voltage on the label this is WRONG!

Like the timbo APPS you adjust to to the point you cross the dead zone and back off below this point 1/2 turn. Reason why is to keep the APPS from accidentally going to OFF idle state. As long as the voltage in the APPS sensor is below this state the the ON idle signal is given to the ECM and the APPS signal is basically ignored and idle programing is used.

Like for my example here the voltage on the tag is .553...

Now if the alternator or voltage of the system change a little bit you going to have issues of the voltage crossing back and forth over this boundary. Please set your voltage BELOW what on the tag by about 0.020 volts to insure the voltage is low enough to put the APPS sensor in ON Idle state.

Problem #2 - Where to measure the voltage?

I do know why they started measure the voltage at the PCM in concerns of the TQ Conv Lock up problem but this is wrong too. Now if you go over to my wiring diagrams here...

http://mopar.mopar1973man.com/cummins/2ndgen24v/wiring/wiring.htm

And now look at Page 1 and look at the PCM on the right at pin #23 you see its labeled ACC PEDAL POS. You think this is tied to the APPS?! Nope... Now switch back to page 3 now at look at the ECM on the right you find the wire at pin #28 on the ECM label ACC PEDAL POS SENS... But now look at all 3 pages this this Orange/Blue wire doesn't connect to the APPS sensor at all but it does pass the information to the PCM after it passes through the ECM (if there is any processing). So now look at Pin #25 on the ECM and you'll see it has a direct connection with the APPS. So if I was going to adjust the stock APPS sensor for voltage I would measure right at the APPS sensor or at the ECM pin #25 which happen to be Light Blue/back wire pin #3 on the APPS.

STOP! Don't measure your APPS voltage at the PCM this is WRONG!

Measure the APPS voltage at the APPS like Timbo does to if your going for better measure it at the ECM. By the time you measure the voltage at the PCM there might be a minor voltage loss so the voltage at the ECM will be high so hence most people complain about high idle, and other issues!

Problem #3 - How to adjust the APPS sensor?

There is no need to yank the sensor apart and mess with the 2 torx screw on the back you can obtain all the adjustment you want in the set screw on the bellcrank. But once again don't adjust for the voltage marked on the label... Make sure to flick the throttle bellcrank to WOT ans let it snap back to idle a few times and check you voltage again if the voltage is changing constantly the APPS sensor is wore out and no amount of adjusting is going to fix this problem.

STOP! Don't bother messing with the 2 torx screw just adjust the set screw on the bellcrank.

1 hour ago, Mopar1973Man said:

@dripley

 

Could be worse we could all buy OEM APPS which should be better but actually its worse off being the logic chip inside to control the IVS states. Timbo's is the best option for APPS sensor. Wells ain't bad but its back to logic chips to control the IVS state again. 

At least my spare is a good one now. 

The el cheapo I took off worked fine at idle and it came off idle fine too. Part throttle, code everytime, code cleared no problem but came back at the same throttle point, I did take voltage measurements but can't remember what they were, I do remember at the code point it was anyhow

Hello All, 

 

I wanted to jump into this thread because I'm experiencing a dead throttle pedal issue as well.  I've replaced the apps with both a Timbo and Wells and no luck.  I had Mechman build me a new alternator thinking that I was getting high AC levels, no luck.  For some reason, the previous owner installed a jumper from the #3 pin on the apps to the 23 pin on the ECM - orange/black wire (data link/fuel inj) .  I'm not following this logic.

 

I drive the truck on Friday 150 miles without a problem but, yesterday I had a dead pedal 7 times in 5 miles. 

 

Ready to sell if I cant get it figured out.

 

Thanks for the help, 

Chris

Edited October 21, 20195 yr by 57pan

I had a similar problem after installing my Wells APPS.

First, the splicing and cutting you are talking about is the ATS fix which by-passes the ECM. 
I undid that fix, but did keep the splice to #4, black/yellow, on the APPS to ground.
I sanded a good ground to the body where a ground wire from the battery connected and replaced the terminal end. 

I think that ground put me over the top on a torque converter lock I have been fighting for a year.

 

After I installed the Wells APPS and tried the setting voltage myth, my idle was over 1100 and I had a reoccurring dead peddle. 
To fix it I readjusted the APPS for free travel, the middle of the torx screw slots and forgot about the voltage.
I disconnected the batteries, again, for over 30+ minutes.
I reconnected them, turned on the key, pressed the peddle to the floor and back up slowly, and started the engine.
My idle went to 850 and I have not had a dead peddle again.

In short, I suspect you need to clear and reset your APPS memory by disconnecting the batteries.
The only other issue could be if someone has jacked around with the idle screw and it is not reaching the idle signal of the APPS.
All the accelerator peddle controls on the engine is the APPS.

Lastly, listen to Mopar1973man over me. 

I know what I did, but he knows what he is doing. 

 

Edited October 21, 20195 yr by Jwirth

Jwirth thank you for the advice.  In another effort in futility, I disconnected the batteries for 2.5 hours today, then reset the apps module after hooking them back up.  To my dismay,  the truck went into dead pedal less than 2 blocks from the house.  

 

Argh!  BTW, I've cleaned every grounding point.  I guess it's back to tracing wires.

 

Codes?

Today's code is P0121 - TPS A circuit range/performance. 

 

Thanks

Should be no wiring mods to the APPS wiring. Either to the signal or ground legs period. Sensor ground is NOT body ground.

Moparman,

 

I finally had some time today to further investigate the spliced wires on my APPs sensor.  The first was with. The blue/green splice to a ground.  The second is the blue/white going to pin 23 of the PCM.  

 

I disconnected both splices and now my wait to start light flashes and the truck wont start.   Does this mean I have a bad ECM and was the blue/white splice a workaround?

 

I should mention that the originally wiring is intact.

 

Thanks,

Chris

Out of curiosity, I reattached the splice going to the ground and my WTS light stopped flashing and the truck started.  I've left the splice to the PCM unhooked for now.

 

Chris

Edited October 31, 20195 yr by 57pan

This is why I do not suggest this mods...

 

Wait to start flashing is a bad thing and the ECM is done.

Well my electrically challenge arse has to ask, Why would grounding the idle validation switch 2 make it work? I kept thinking maybe something was bad in the ground splice in the harness but those wires are blk/lt blu for the sensor grounds.