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

[Gary - K7GLD]

Gary,



I think they're wrong about this too...



From my reading of the Williams Throttle Controls cataog, service kit part number 131167 contains some screws and a sensor WITHOUT an intigrated IVS. The sensor for this service kit is Williams part number 130656 and the current cost is $86. 96. The sensor alone is not available seperately from the service kit. The sensor included in this service kit appears nearly identical to the one with an IVS from service kit number 131973, but the coupler on it is narrower and has only 3 wires instead of 6.



According to the WIlliams catalog, if you use the non-IVS APPS in service kit 131167, you would want to use Wiring Harness number 130063. It's available online for only $17. 50.



What I can't say in all this is whether or not the resistance values of the Williams APPS without the integrated IVS is the same as the one with an integrated IVS. My hunch is they would be the same in order to comply with SAE J1843 specifications. But someone would have to buy one and test it to be sure.



Best regards,



John L.

John, I saw that unit as well, and it certainly SEEMS to be as you suggest, but the Williams tech was pretty definite as to ALL their setups including the IVS circuitry - but if so, WHERE are the IVS pins?



I think you (and I!) are correct that that module does NOT include the IVS, and as you point out, all these module potentiometer sections are most likely all in the 2500 ohm range to meet SAE spec.



I may go ahead and buy one to verify, only thing remaining is, does it's base mount arrangement still match up direct with the DC bracket arrangement...

 

[Gary - K7GLD]

Gary,



I know this is a massive WAG (wild a. . guess) but,



From your experience, what is the % of totally failed dc APPS to APPS that have "failed"? ie what % of the APPS you have looked at could at least the pot still be used? WHICH lends crediability to the micro switch approach.



From your comment about being totally shot in the pot section (1 dc APPS) vs XX APPS you have looked at. Maybe 5% totally dead?, 95% APPS pot still usable?



Then those of us that go the micro switch route could run an extremely long time off the "failed dc APPS" of other members for several decades. Just have to set up a place for the membership to send their "dead" APPS.



Bob Weis

Bob, I've had over a half dozen "failed" APPS modules, and the one I received yesterday was the FIRST that clearly was defective in the potentiometer section - can't speak as to the IVS sections, and I personally suspect LOTS of APPS modules got swapped out when it was actually some other component that was failing and displaying similar symptoms, such as the VP-44...



And yes, I also feel that quite a few miles could easily be left in MANY supposedly "failed" APPS modules by use of the external MS for the IVS function. They are certainly easily checked for proper potentiometer operation, unlike the IVS section...



And the neat thing is, as long as there is a properly operating IVS device, like the MS, failure of the potentiometer section is usually gradual, and not likely to leave the owner stranded along the road unexpectedly.

 

[JLandry]

I may go ahead and buy one to verify, only thing remaining is, does it's base mount arrangement still match up direct with the DC bracket arrangement...

Gary,



I suspect it'll fit just fine because the SAE J1843 spec also calls out the APPS bolt hole spacing, etc.



John L.

 

[Gary - K7GLD]

LOOK at what just arrived in the mail from TDR member Prout - Phil REALLY went the second mile, and sent me a COMPLETE APPS unit, including engine mount and the APPS cover!



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OUTSTANDING!



Since I'm now working up MS mounts that use the APPS bracket bolts, this will allow me to do all that fabricating and fitting on the work bench, instead of the engine -



THANKS A MILLION PHIL!



Just for grins, I shot this pic, showing the actual APPS module as seen from underneath:



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Interesting to note, that the APPS bracket itself is attached to 1/8 inch standoffs cast into the engine bracket. Bob has drilled additional holes in the topside of that engine bracket for added ventilation along with the blown ducted air from the outside of the engine bay, much as I have done on mine:



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On mine, the airflow around the APPS mount edges is quite noticeable, and undoubtedly assists cooling of the OEM APPS module.

 

[Gary - K7GLD]

HMMmmmmm - I just discovered something interesting - at least on the Williams APPS I have in front of me...



The wiper at rest is completely off the resistance track - dunno if there is a decent mechanical stop on each end of wiper travel or not to protect from damagung overtravel, but I kept getting ZERO, open circuit ohms, when I attempted to do an ohms check on mine.



Probably not an issue in normal installation, but sure something to be aware of...

 

[timbo]

I have a bellcrank for both and the travel is exactly the same. Bob might have a diff sensor than us. I've bench tested every sensor so far about 12. When the sensor is off the bracket and all the way at the and of the travel, voltage is 0. Then using a straight screwdriver, Begin to rotate it clockwise about 2 deg, voltage comes up to . 62-67 (THEN VOLTAGE STAYS EXACTLY THE SAME for about 4-5 deg of rotation then it rises as normal. That is why JLandry has a to move the petal slightly to begin to Rev up. I bench test using 3 voltmeters, wired into a male duetz plug, 1 to read voltage,1 to read Idle continuity,1 to read OFF idle continuity. I then bolt it up to the bracket and watch it perform on the meters.

Gary, this was my exact finding also,back on post 536. I would definitly think there is a mechanical stop inside so it would not stress the wiper. When it's installed on the bellcrank it will never go that far back(even with the idle stop screw all the way out). I also tested it when it was installed on the billet adapter. I found that they have the mechanical stop in the adapter set so as soon as you rotate the splined shaft voltage rises immediately.

 

[JLandry]

Gary, this was my exact finding also,back on post 536.

Ditto here with my Williams APPS.



John L.

 

[Gary - K7GLD]

Ditto here with my Williams APPS.



John L.

OK, guess it's normal then - didn't catch that in Timbo's earlier voltage related thread, since in my setups, voltage doesn't seem to be an issue for installation, so don't follow that characteristic too closely.



Sort of unusual tho', as far as "normal" potentiometer function is concerned.

 

[Gary - K7GLD]

OK, got the "final-final" bracket made up for the separate MS IVS versions of what all this thread has seemingly boiled down to. Nothing radical by any means, just a simple fabrication out of some 1 inch perforated strap material from some long past car stereo install - here's the piece cut, formed and fitted:



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And, how it installs on the APPS bracket:



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Note how the notch in the end grips the post, keeps the MS bracket properly located in relation to the belcrank, and with tension on it, is quite stiff. Also note the minor notch on the bracket to allow clearance for the belcrank return spring tab.



And here it all is with the MS installed:



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That's about it for me on this particular approach using the MS with any of several forms of separate potentiometer sections - this last bracket would seem easily within the abilities of almost any Dodge owner wanting to keep expenses (and labor! :-laf)to a bare minimum.



This has all been fun, and some may have noticed that I sorta enjoy projects of this nature - twiddling with adaptations and work-arounds is what often helped me keep everything from printing presses to computers and networks running at the newspaper before I retired - not to mention my own electronic and mechanical stuff at home.



Good luck to any and all who work at some form of adapting what you have seen here to your own use and benefit!

 

[JLandry]

Beautiful craftsmaship Gary.



Tomorrow morning I'm off on a 1500 mile round trip towing my travel trailer across 4 states. That ought to be a solid test for the new Williams APPS I've installed.



With 200 miles on it locally, so far so good. Smooth as silk.



John L.

 

[rweis]

Gary,



BEST bracket yet!



1 piece, no welding, solid fit to the idle set screw casting, angular fit to the bell crank work able with a little "pushing 'n pulling", stable, clears the bellcrank spring attach point. Should be able to be bolted in real nice and tight so no movement over time / vibration.



Looks like it meets ALL the criteria.



I knew you would come up with the most cost effective, most simplistic, best way to do this.



My hats off to you again, let's see:



VP44 blower timer, fuel bypass returns, APPS, lp testing, and I am sure many many more I have forgotten.



Bob Weis

 

[BradPatterson]

Timbo, I have about 1500 miles on your "new" Williams Apps that you sent and it works flawlessly, no problems at all, Thanks man... ... Brad

 

[rweis]

Is ANYONE having problems with their "new" Williams APPS yet?



Just thought I'd ask, speak up if something is not right!



Gary,



In a month or so I am going back to ABC bus and see if they will order me ALL of the NON IVS APPS and will take the extra APPS bracket and do "test fits" to see IF any of the NON IVS APPS will be an exact fit.



I think I can convence them if I do not hook anything up to electrical power then it is returnable. I'll do the fit testing right at the parts counter in front of them.



Bob Weis

 

[mhenon]

Is ANYONE having problems with their "new" Williams APPS yet?...

Bob, No problems so far. How's yours doing? No more codes I take it?

Mike

 

[Gary - K7GLD]

Gary,



In a month or so I am going back to ABC bus and see if they will order me ALL of the NON IVS APPS and will take the extra APPS bracket and do "test fits" to see IF any of the NON IVS APPS will be an exact fit.



I think I can convence them if I do not hook anything up to electrical power then it is returnable. I'll do the fit testing right at the parts counter in front of them.



Bob Weis

Sounds like a great idea - for some of us trying several different approaches, and even with the thoughtful help of volunteers sending us the APPS brackets at no cost, the stuff we DO have to buy adds up after a while. I'd love to try one of the "NON-IVS" versions of the Williams APPS, but have already spent over $100 on the IVS version I bought - and adding another $75 or so on a pure gamble is sorta over the top, especially with the other options already KNOWN to work well... :-laf

 

[DFoster]

Bob,

It's working great! No codes, smooth.

Dale

 

[rweis]

Mine is doing fine as well.



I am going to get with Williams Controlls and start asking about the physical differences of the different APPS. See if they have physical drawings of the shapes. See if different APPS have different electrical characteristics.



Pick a same physical size but non IVS, get ABC bus to order one, test the physical fit right there with the counter guys, and if a exact match then purchase it.



Swap it and run it for the micro switch IVS group. See if we can't get the $$ down some. Might be a too small diference in $$, might be significant $$.



With a known good solution (131973), I am not going to post every bend and turn, just what the outcome is.



Might take some time to gather all the information, but seems like a good thing to try.



Bob Weis

 

[FLynes]

So a non-IVS doesn't confuse the truck? This is going to sound dumb, and please forgive the ignorance, but how does the idle get validated if there is no switch to do it?



By the way, once this thing becomes a done deal, put me down for one! I absolutely love the ingenuity of TDR members!

 

[rweis]

So a non-IVS doesn't confuse the truck? This is going to sound dumb, and please forgive the ignorance, but how does the idle get validated if there is no switch to do it? ... ... .

The NON IVS APPS you HAVE to do the IVS somehow else.



The TDR folks that want to get rid of the IVS electronics (Gary thinks that the IVS circuitry is the highest probablity reason most APPS "fail") do the IVS with the micro switch riding on the bell crank.



By seperating the APPS from the IVS you have narrowed the APPS "pass / fail" decision to a simple "yes / no". Either the potentiometer works or not and is easily testable. You narrow the IVS "pass / fail" decision to a simple "yes / no". Either the micro switch makes contact or it does not and is easily testable.



You get rid of the "well, it could be the APPS potentiometer OR the IVS circuitry" with the IVS circuitry the most probable as stated above. You also should (have to find this out) have a cheaper APPS, and the micro switch from Mouser Electronics is ~$6. 00 good for 2,000,000 cycles MTBF. Should be a cheaper total install with the utmost in reliability.



You do have to make a micro switch bracket of your choice (Gary has demo 3 of them and I demo 1 of them).



I think Gary is running a micro switch IVS right now, I am running a micro switch IVS right now. Not sure who else is running a micro switch IVS.



Bob Weis

 

[Gary - K7GLD]

YUP - I'm still running the $2 stereo in-line potentiometer, and the $8 micro switch, and all is well... :-laf:-laf



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