Can someone please explain?

[rjones]

03 and 04 APPS under the battery OEM replacement ... . I know its a TPS of some sort correct? but what is meant by under the battery?

http://www.dodgecumminsapps.com/index.html

 

[rscurtis]

IIRC, the standard transmission trucks used an APPS located under the driver's side battery, where the automatic trucks used an engine mounted APPS.

 

[rjones]

Thank You for that info

 

[Prairie Dog]

Depends on the build date too. Mine is on the eng even though I have a manual.

 

[rbattelle]

Depends on the build date too. Mine is on the eng even though I have a manual.

Early build 2003s had a big APPS mounted just forward of the intake horn regardless of the transmission. It uses a linear potentiometer, I think.



I think it was some time between January 2003 and February 2003 when they switched the manual trucks over to the hall-effect sensor mounted beneath the driver side battery. My truck was built 28 February 2003, and I have the hall effect sensor beneath the battery.



Prairie, does your truck also have a vacuum pump? I can't remember if the APPS you have requires a vacuum pump for cruise control.



-Ryan

 

[Prairie Dog]

Early build 2003s had a big APPS mounted just forward of the intake horn regardless of the transmission. It uses a linear potentiometer, I think.



I think it was some time between January 2003 and February 2003 when they switched the manual trucks over to the hall-effect sensor mounted beneath the driver side battery. My truck was built 28 February 2003, and I have the hall effect sensor beneath the battery.



Prairie, does your truck also have a vacuum pump? I can't remember if the APPS you have requires a vacuum pump for cruise control.



-Ryan

You know Ryan, I'm a little embarrassed to say it but. . I'm not sure where a vac. pump would be. It aint behind the PS pump like my 03 (I think)! Where the heck would it be?

 

[cerberusiam]

Usually between the driver side battery and the fender tucked out of the way.

 

[Prairie Dog]

Usually between the driver side battery and the fender tucked out of the way.

I don't see anything under the batt, there's the fuse box in front and the antilock module behind it. Also, don't see any vac line going to the APPS.

 

[cerberusiam]

Also, don't see any vac line going to the APPS.

Vaccuum line won't go to the APPS, it will go to the CC control module then a cable to the APPS bell crank. How many cables do you have coming off the APPS bell crank and where do they go?



If you have speed control rather than CC it may be in the ECU rather than a seperate unit like CC.

 

[Prairie Dog]

Vaccuum line won't go to the APPS, it will go to the CC control module then a cable to the APPS bell crank. How many cables do you have coming off the APPS bell crank and where do they go?

If you have speed control rather than CC it may be in the ECU rather than a seperate unit like CC.

There's only one cable and that goes through the upper portion of the firewall for the throttle. Then there's a wire harness.
I seem to remember reading that the CC was ECM based and that if a universal CR eng was used (like the ones they used to sell on eBay) it probably won't have CC capability and it couldn't be added either.

If the GDP filter wasn't in the way I would remove the cover to the APPS and post a pic.

 

[cerberusiam]

Do you have speed control?

 

[Prairie Dog]

Do you have speed control?

Yup, and and now I have to type something extra because "Yup" is is not enough characters according to the sites requirements. #@$%!

 

[cerberusiam]

when they switched the manual trucks over to the hall-effect sensor mounted beneath the driver side battery.

Don't think its a hall effect sensor but rather a slightly different potentiometer. It could be either a linear or algorithmic type but pretty sure it is still a potentiometer.

 

[Prairie Dog]

I sure hope it's not a pot. They're so much more prone to failure.

 

[cerberusiam]

I sure hope it's not a pot. They're so much more prone to failure.

Pretty sure the engine mounted APPS is a linear taper potentiometer since the shaft rotation of the bell crank is the control point.



Mount something electronic a big vibrating hunk oif metal in extreme conditions I would guess the MTBF would be suspect. :-laf



A pot is more prone to failure as opposed to what? A hall effect sensor does not serve the same purpose as a potentiometer. Different application, different contruction.

 

[Prairie Dog]

Pretty sure the engine mounted APPS is a linear taper potentiometer since the shaft rotation of the bell crank is the control point.



Mount something electronic a big vibrating hunk oif metal in extreme conditions I would guess the MTBF would be suspect. :-laf



A pot is more prone to failure as opposed to what? A hall effect sensor does not serve the same purpose as a potentiometer. Different application, different contruction.

A pot as opposed the the HE sensor. I know it's not the exact same thing but with different circuitry, the HE can be used instead of pots in a situation like this (electronic throttles) and has almost nothing to wear out.

Thankfully pots have all but disappeared in modern electronics. I can't tell you how many I've replaced throughout the years in the avionics I worked on.

 

[cerberusiam]

That really depends on usage and control specs. A digital potentiometer can function like an analog one but it has its drawbacks in finite control.



AFAIK, the APPS is a classic dual anlaog potentiometer. I think the what you are seeing is better manufacturing and materials rather than disappearance in a lot of applications.



A throttle control that is based on a shaft rotation from a mechanical input is easily and cheaply done with linear pot. Keyword here is "cheap". :-laf The addition of another pot plus the algorithms in the ECU to use both inputs while discarding and out range one seems to be the trend. Its cheaper and more effective to do it that way than spend the $$ on a high end solution.



What specific parts that were pots are you seeing disappearing and what are they replaced with?



It seems I can go to any electronics store and get all manner of potetiometers to do about anything, if I can decipher their specs which I can't most of the time.

 

[Prairie Dog]

No, believe me pots are mostly gone in manufacturing but of course you can still buy them. Modern circuit design has changed dramatically from the days of using PCB mounted trim pots that were used to fine tune resistance values and component responses. Circuits are more apt to tune themselves or be so tightly designed that the days of tech sitting around making tiny adjustments and observing responses is gone. Typical new designs will replace 1 or more PCB's with a single hybrid array. The older stuff was easier to troubleshoot though!

 

[cerberusiam]

Sure, in the context you describe they are obsolete. Much better ways than a worm gear potetiometer to self adjust. Now instead of replacing components you replace a board completely.



Back to an APPS in these trucks, what could be used to replace the APPS that has to take a human usable mechaincal input and translate that to a digital signal to control engine rpms?



To use a HE sensor you would need something like a gyro stabilizer that would react to mechaincal input to translate a movement. Something like gyros stabilizing a gimbaled engine mount on a launch vehicle for minute thrust adjustments, or even a cutting edge fighter jet where minimal movments get expanded and multiple systems are effected to make a simple turn.



Lets face it, our TV's are higher tech than the control systems on these trucks, they simply AIN'T rocket science and Dodge did not contract NASA. :-laf



Plain and simple, we got cheaped.

 

[Prairie Dog]

Oh ya, I noticed lots of stuff done on the cheap.
Hopefully the new ones are HE. Even my wifes Prius has HE TPS.