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

[Gary - K7GLD]

OKAYYyyyyy - here's my relatively finished version #1, using the in-line potentiometer - only need final wiring, once my plug arrives, and I get my OEM APPS off the truck so I can measure and duplicate it's resistance:



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That's the pot side, showing brackets, and the pre-loading spring that maintains solid, no-slop motion between the belcrank and the pot slider. All motion is smooth as silk!



Here's the other side, showing the MS and it's physical mount in relation to the rim of the belcrank - the bracket itself is not visible, but is the same sort of L-shaped bracket as the others seen, inverted, and is bolted to the idle side post:



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The MS adjustment is a piece of cake - plenty of range of adjustment, and the switch works great!



NOW, when the plug arrives, and a bit of finish wiring, and it's DONE! Oo.

 

[Gary - K7GLD]

The SM says to use 2 screwdrivers. Maybe not the best solution though.



Bob Weis

Use them how?



Do the 2 halves, one on each side of the APPS bracket, "snap" apart from each other? If so, the heat gun suggested might be a good idea...

 

[mhenon]

Wait... I was talking about the arm that snaps (plastic socket to metal ball) on to the ball on the bellcrank. I think I know what you're referring to now and I'm not sure how they seperate.

 

[rweis]

I think you wedge one on each side between the throttle connector that goes to the throttle cable and wedge off that connector off the central pin. Not very elegant though.



Bob Weis

 

[rweis]

On the relays,



They are Bosch type 20 amp automotive relays with 5 pins. They do have a diode across the coil for voltage spikes. The relays come as high as 50 amp capability. There is a DUAL RELAY standard mounting package (330-078) that would significantly simplify the install. I used two single relay sockets (330-075) not knowing about the dual socket. You can also get the socket with the diode (330-076). Partsexpress.com is a typical supplier.



The relays with the diode are about $10. The ones without the diode are about $2. 75. I only buy the ones with the diode.



I would think a 50 amp relay with diode and sealed marine duty (the very best relay you can get I think) would be the best option for the application.



Just some ideas about the relays. I bought a set of 50 amp sealed diode protected (and a spare set) because I think they are the best I can find and should be the longest lasting.



Bob Weis



The more I think about the application the better I like the bus APPS. Exact mechanical fit, everything else is soldering, no machining, universal fit to ALL APPS applications (stick, auto transmission, cruise control, what ever).



With 5 volts to the IVS it might last longer as it might be a wiper contact with 5 volt power just like the APPS pot side and no electronics.

 

[Gary - K7GLD]

Wait... I was talking about the arm that snaps (plastic socket to metal ball) on to the ball on the bellcrank. I think I know what you're referring to now and I'm not sure how they seperate.

Well, the issue of getting the ball off with minimal damage was my next question... :-laf





But, both items are a concern, if they are to be reused and/or removed several times - I had sorta figured others here had removed them, and knew the "secret"...

 

[rweis]

Gary,



It pops off and on.



I have had mine off / on about 3 or 4 times.



The plastic socket toward the bell crank expands enough to allow the ball to pass through then it returns to its orgional size.



It takes some force to get it to go over the ball, hence the 2 screwdrivers to act as wedges between the throttle adapter and the bell crank body to wedge it off.



The speed control and the auto transmission clips are pulled toward the front of the APPS housing direction. IF you twist those fittings you break them.



Bob Weis

 

[Gary - K7GLD]

Gary,



It pops off and on.



I have had mine off / on about 3 or 4 times.



The plastic socket toward the bell crank expands enough to allow the ball to pass through then it returns to its orgional size.



It takes some force to get it to go over the ball, hence the 2 screwdrivers to act as wedges between the throttle adapter and the bell crank body to wedge it off. The speed control and the auto transmission clips are pulled toward the front of the APPS housing direction. IF you twist those fittings you break them.



Bob Weis

Thanks Bob - always prefer to benefit from the experience of others!



Today, I'm working on getting the potentiometer section of the OEM APPS finished up for trial, plus a small bit of finish work on the replacement APPS setup I worked on yesterday - I want to get the primary wiring and the IVS noise filter done, so that when the plug arrives - hopefully today - that will be all remaining to wire...

 

[Gary - K7GLD]

OK, got the OEM APPS module wired and ready to install - remember, the part needing connection after cutting off the pin connector neck looks like THIS:



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SO, I needed to solder wire to the appropriate trace pads that connected ONLY to the position sensor potentiometer. Fortunately, I had some networking wire left from my newspaper systems administrator work to use - it has silver plated conductors, and Teflon insulation.



The finished module looks like this, after soldering the wires and encasing the whole shebang in epoxy:



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The goal here, and my thinking, is that even though this module was replaced as failed, the potentiometer section seems to be just fine - tho' I have no idea how many miles are on it. I did go ahead and apply a good spray of contact cleaner to the potentiometer section prior to sealing everything up tight.



As mentioned earlier in this thread, there are a variety of reasons for these modules to fail - heat/vibration damage to the solid state circuitry, failed electronic connection between the membrane traces to the pin connector, and of course, the potentiometer section itself.



But IF there are a number of these "used/failed" modules floating around that still check good as far as the potentiometer section is concerned, and users are willing to modify and experiment (after all, THIS effort is no harder than what some of us are trying with other methods), This approach certainly eliminates LOTS of adapting and addition of other components to do the same function - and leaves only the relatively simple and inexpensive installation of the outboard microswitch for the IVS function!

 

[Gary - K7GLD]

PHEWwwww - APPS all wired and ready for the plug:



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The assembly of resistors/capacitors is the noise filter network for the IVS microswitch contacts, larger sized components than actually needed, but what was in my electronics junkbox - the other terminal strip to lower right is for adding whatever value padding resistors needed to match the OEM APPS when I remove it from the truck and check it.

 

[rweis]

Gary,



HOW did you solder the wire to the IC pad? That looks like very very fine detail soldering.



Bob Weis

 

[rweis]

I went back and re read the whole thread to see if a specific method was justifiably better or worse than the others.



Using the dc APPS like Gary has done above with a MS I think is best, least expensive and less complicated. The dc APPS uses ground to do the IVS function and therefore a MS. Using the dc APPS will make it usable to all configurations (stick, autos, speed control)



Second seems to be the Mustang APPS except the mounting bracket has to be made. The Mustang APPS uses ground to do the IVS function and therefore a MS. Usable to all configurations.



The bus APPS is a mechanical fit BUT you have to add a double relay set to do the IVS function, which adds complication. MAYBE because it uses 5 volts it will be tough enough to with stand the environment. Usable to all configurations.



I am going to drill vent holes in the top of the APPS enclosure bracket to help it vent the heat (and I use a blower to the Vp44 so some of the blower air will help keep the APPS cool).



Time will tell which system works well,



WHAT A WONDERFUL EFFORT BY ALL, TRUE TDR COMRADERIE, HELP, ENCOURAGEMENT, PERSPECTIVE, PERSISTANCE, RESOURCES AND IDEAS FROM EVERYONE, ENDING IN SOLUTIONS Oo.



Many, Many Thanks



Bob Weis



I am driving my bus APPS to see how it does over time. I will tow heavy with it in a couple of weeks and that should wind up the testing. I chuckle when I think my dc APPS is a SPARE, you gotta LOVE it!

 

[rweis]

I was over at the williamscontrols.com site gathering documentation information. I looked through the different APPS they manufacture.



The DDEC II APPS looks exactely like the Cummins APPS BUT it does NOT have the IVS function. Which means we might be able to use the DDEC II APPS and the MS like Gary is doing with the dc APPS and the MS.



Just a thought since we pretty well have found that just about any APPS will work. It would solve the problem of building the relay package to make the Cummins APPS work, and not have to build a bracket for the Mustang APPS.



This assumes the DDEC II APPS can be had at a reasonable price, it would fit exactely and your dc APPS pot is non functional and you have to purchase an APPS pot of some sort.



It appears that any of the APPS on the WM526 specification page would fit their pedal assembly and therefore would have the right hole spacing for the dc APPS bracket. The DDEC II sensor has the same shape as the Cummins sensor and just might have the same body and fitment.



That might be a source of a reasonable cost exact fit for the APPS portion, then MS for the IVS portion.



Anyone game to try that approach?



Bob Weis

 

[Gary - K7GLD]

I went back and re read the whole thread to see if a specific method was justifiably better or worse than the others.



Using the dc APPS like Gary has done above with a MS I think is best, least expensive and less complicated. The dc APPS uses ground to do the IVS function and therefore a MS. Using the dc APPS will make it usable to all configurations (stick, autos, speed control)



Second seems to be the Mustang APPS except the mounting bracket has to be made. The Mustang APPS uses ground to do the IVS function and therefore a MS. Usable to all configurations.



The bus APPS is a mechanical fit BUT you have to add a double relay set to do the IVS function, which adds complication. MAYBE because it uses 5 volts it will be tough enough to with stand the environment. Usable to all configurations.



I am going to drill vent holes in the top of the APPS enclosure bracket to help it vent the heat (and I use a blower to the Vp44 so some of the blower air will help keep the APPS cool).



Time will tell which system works well,



WHAT A WONDERFUL EFFORT BY ALL, TRUE TDR COMRADERIE, HELP, ENCOURAGEMENT, PERSPECTIVE, PERSISTANCE, RESOURCES AND IDEAS FROM EVERYONE, ENDING IN SOLUTIONS Oo.



Many, Many Thanks



Bob Weis



I am driving my bus APPS to see how it does over time. I will tow heavy with it in a couple of weeks and that should wind up the testing. I chuckle when I think my dc APPS is a SPARE, you gotta LOVE it!

I agree fully - of the 3 methods developed so far, I really like the cleanness of Timbos, it is fully compatible with both transmission types, parts are easily located and replaced as necessary, and SHOULD be far longer lived and less vulnerable than the OEM APPS. The only issue seems to be the adaptation components needed to allow the use of the Mustang potentiometer - not too many here have lathes to make their own adapters.



Bob's seems potentially effective, but DOES introduce it's own level of complexity into the mix, with added potential failure items.



My own, assuming decent lifespan out of the potentiometer - and other, more durable ones ARE available, may well be more mechanically involved as to fabricating brackets and linkage is concerned, than most guys would attempt. It's not as hard as it seems, but the other downside, is that it would apply only to a manual transmission truck.



The modification of the existing APPS module WOULD be the easiest approach, fits all transmission types, requires only the added IVS MS - but would ALSO require a good source of doner APPS modules - and still introduces the unknown issue as to what lifespan could be expected from what is a USED component.

Gary,



HOW did you solder the wire to the IC pad? That looks like very very fine detail soldering.



Bob Weis

Really not difficult - just requires a delicate touch and fast work with silver solder to avoid burning up the traces and Mylar backing.



Yeah, if a good source of identical physical replacement potentiometers could be located at a price substantially lower than the existing APPS, that would be the ticket.



Otherwise, I fear that regardless of the success of our individual efforts, the accompanying levels of individual fabrication and adaptation will render what we have done as interesting reading for most, but not likely to be widely copied...



Anyway, if my adapter plug doesn't arrive today, I'll go ahead and adapt/install the plug section removed from the OEM APPS I displayed earlier, and go ahead and install my own APPS replacement. Should have something to report by the end of the day, if other complications don't arise.



This thread has been running almost exactly 4 years now - we've come a long ways, and even though we now have what appears to be 3 different working "solutions", there has to be LOTS of trouble-free over-the-road success before what we've developed can BEGIN to be considered a "success". I wish I had a way to install and try BOTH the modified APPS unit AND the one I now have finished - but that isn't possible, so the in-line pot version will go in first for trial...



More later!

 

[FLynes]

Gary, Bob and Timbo,



I truly admire all of the work you guys have put into finding an alternative to our plight, but I pulling out my Debit Card and paying for a new APPS is going to be ultimately faster than trying to build my own. My father, who was an engineer at Westinghouse, is rolling in his grave. I read these posts and follow as best I can, but I have to admit that sometimes I feel like Charlie Brown, when he was listening to the grown-ups talk.

 

[rweis]

What I like about the inline pot is there are NO electronics (just a couple of noise filters).



The "electronics" of the bus APPS drove the additional relay set complexity (which I tried to not do, but in the long run had to do). It works, but.



I think a high grade pot and a MS is the best bet. I think it has to be a potentiometer on the back side because of the lack of space on the front side. The MS seems to be easily mountable where ya'll are mounting it. It would be universal to all trucks as well. I think the cost would drop to under $50 for the pot and the MS. The MS has been verified acceptable to be mounted to actuate against the bell crank arm.



From the blade end of the actuator of the bell crank on the APPS side the pot shaft could be slotted to accept it. The pot mounting bracket like the bracket Gary has in one of his pictures. Screw the pot bracket to the APPS bracket. I am just not totally thrilled with the added relays and still have an electronic circuit mounted in a hot box (the pocket where the APPS device is mounted). Too much probability of failure, too much "stuff".



I am waiting until someone else gets their's working because of the CEL code I am getting. If I can not reset it with the APPS reset procedure to make the ECM understand what is going on, then there has to be some sort of voltage above ground for the ECM. That confuses me . If the ECM wants ground and I give it ground then why is the IVS signal voltage too low? Strange. Could be a left over value from the dc APPS still in the ECM.



I think I am going to run this bus APPS for a while, but still work toward the ultra simple - pot + MS.



Bob Weis

 

[Gary - K7GLD]

AND, we have LIFTOFF!!! Oo. Oo.



I went ahead and soldered leads to the pin connector earlier cut off my old APPS module, and encased the connection with epoxy:



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Soldered the pigtail from the APPS, carefully applied shrink wrap tubing at each soldered connection, installed protective sheathing, and here she be - all ready to install:



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I wanted to use the short leads in case I later decide to install the other plug when it arrives, and might also want to use it if/when I try the modified OEM APPS in the potentiometer-only mode.



Next, I removed the APPS off my truck, and carefully measured the resistance, both end-to end (2400 ohms), the "resting/idle" resistance (300 ohms), and the WOT resistance (1900 ohms). Then I manually adjusted the start of the stroke of the in-line pot to 300 ohms - the WOT closely matched the OEM APPS at 1900 ohms, so all I then needed was about 500 ohms added to the WOT end of the slider - I had a 470 ohm 2 watt precision resistor in my junkbox - so I was IN!



Mounted the setup on the truck, reconnected the batteries, turned on the ignition, no codes or lights, did the "reset the APPS" bit, and switched on the ignition, and she fired right up like normal - no lights, codes or abnormalities - and drives just like always! Oo.



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Guys, I think we're done here... :-laf:-laf

 

[Gary - K7GLD]

HEY BOB - if you want to go to a microswitch for the IVS function, and are willing to install the modded used APPS module I have, I can send it to you...

 

[Gary - K7GLD]

Gary, Bob and Timbo,



I truly admire all of the work you guys have put into finding an alternative to our plight, but I pulling out my Debit Card and paying for a new APPS is going to be ultimately faster than trying to build my own. My father, who was an engineer at Westinghouse, is rolling in his grave. I read these posts and follow as best I can, but I have to admit that sometimes I feel like Charlie Brown, when he was listening to the grown-ups talk.

Fred, it's not really all that complicated - to a degree... :-laf



The single biggest breakthrough, was when it was discovered that virtually ALL that the complex-looking solid state circuitry was doing inside the APPS module was electronically substituting for a simple mechanical DPST switch!



Once THAT was established, the remaining task was that of coming up with an alternative switch - the microswitch has proved effective so far - and some form of 2500 ohm or so variable to replace that function of the OEM APPS - so far, several methods have surfaced, undoubtedly more to follow!



BUT - as you point out, MOST guys haven't the time, resources or inclination to do what the 3 (so far) of us have done. Like you say, it's far quicker and easier to drag out the CC, and just PAY the man, and get it done...



But then, there's the NEXT time that CC has to be dragged out for the SAME thing, all over again - and lets face it, the cost of the OEM APPS is nearly HALF the cost of a rebuilt VP-44!



Once the initial investment of time, $$$ and effort has been accomplished, further component replacements (if any!) are fast, easy and CHEAP - the potentiometer in my setup was *$2* - the microswitch about $10 or so as I recall - the rest of the components were nickle and dime stuff, or junkbox items.



At this point, in my case, there are NO MORE temperature sensitive or flimsy surface-mount printed circuit items, or Micky Mouse pressure (prayer!) connections waiting to fail. My potentiometer is a cheapie - but even at that, appears FAR more sturdy than what DC gave us - time will tell. And at $2 a pop, I can pretty well afford to replace mine every year or 2 if needed - or perhaps come up with a better quality and longer life one for a few $$$ more. The microswitch is a 2 million cycle item, but is also quickly and easily changed if required.



One other feature of my own specific unit is, I can easily leave the OEM APPS mounted in place, but disconnected - and switch from it, to my own, in the time it takes to get to the plugs to make the change. Added to that, is the ability to go ahead and install all the stuff I have, in readiness or backup for the OEM APPS, and use it when needed - or never if not... It only costs the few $$$ already mentioned - cheap but effective insurance!

 

[mhenon]

I am waiting until someone else gets their's working because of the CEL code I am getting. If I can not reset it with the APPS reset procedure to make the ECM understand what is going on, then there has to be some sort of voltage above ground for the ECM. That confuses me . If the ECM wants ground and I give it ground then why is the IVS signal voltage too low? Strange. Could be a left over value from the dc APPS still in the ECM.

Bob Weis

Bob, What voltage is low? Are you talking about the voltage at pin 23 on the PCM or the IVS supply voltage (should be 5 volts right)?

If it's the voltage at the IVS a couple things come to mind. You tapped this 5v from the wiper side of the APPS if I remember right. I wonder if this is too much drain for that supply?

Also, I was looking at the relays you're using. They're super heavy duty 12 volt relays and it might be that the coil in the relays is dropping the 5 volt supply down.

One more thing... you said you could hear the contacts clicking in the relays. Could they be firing too slowly for this application? That might be causing the code.

Just tossing out some ideas. The fact that you got it working tells me you're real close here.

Mike

ps: just got home. I ordered the digi-key 5v reed relays and a

small general purpose PC board to mount them. I'll dig through my

Ham junk pile and see if something will work while I'm waiting.