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

[Gary - K7GLD]

From what I can see, and judging by the light-duty aspects of the DC OEM APPS internal components, we're dealing with relatively SMALL signal levels and current flow - so overkill in the size and ratings of components such as relay contacts and resistor dissipation is pretty much unneeded...

 

[rweis]

Yes Gary I'll take it. Let me know the postage and any $$ you have in it.



I was comming home today and thinking "why mess with the IVS relays etc, just put the MS on it" The bus APPS seperates out the APPS pot and the IVS, just do not use their IVS, duh (reminds me of the country song "what was I thinking")



That will make it a lot simplier and get rid of the complexity of the relays. I'll have to read back and see which OEM wire (pin) goes to which function of the switch (center, no, nc). I think center = ground, no=Idle, nc=Throttle, right? I assume drilling right through the bracket and putting the ms on a couple of stancion standoffs should work.



I have no idea why I have been puzzleing this MIL voltage thing. DUMP the bus APPS IVS and go the MS route. Why I get so tunnel visioned I have no idea . I also wanted someone to actually crank her up with the MS in place.



I am going to order the high grade potentiometer and mount it to the backside of the bracket before I get done with this. A potentiometer and the MS are the key like Gary has done and get rid of the "electronics".



Bob Weis

 

[Gary - K7GLD]

Glad to send it Bob - this way, we'll get a better idea as to what to expect from the potentiometer section of the DC APPS, once the IVS switching garbage is abandoned - it would take WAY too long for me to run up miles on what I now have, and THEN switch over to the DC nodule for it's needed test run.



Email or PM me your address again for shipment please.



I sure was happy to see my own setup take off so trouble free - I think it was the attention to getting all the resistance measurements to match the APPS I removed from the truck that did the trick - plus, I suspect we apply way too much mystery and awe to the "sophistication" of the DC APPS - I think it and the ECM have LOTS more latitude and room for variables than we think. Certainly, in my case, it was NOT the expertise or extreme preciseness of setup or adjustment that made it work! :-laf:-laf



As I mentioned earlier, there are varying levels of challenge and effort required in setting up these alternatives to the OEM APPS - and guys looking for or expecting a fast and easy "Plug and play" replacement are going to be disappointed. My own version took about a day's time in total to assemble - at a cost of roughly $30 for the finished product, but since the DC alternative runs well over $400, I figure it was a days worth of effort well spent!

 

[FLynes]

Okay, so with the finished product, are the CELs staying off?

 

[Gary - K7GLD]

Okay, so with the finished product, are the CELs staying off?

AH, you missed THIS part of my earlier post:

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!

Have driven the truck several times - mostly short-haul trips, had the throttle from idle to redline - smooth as glass, no codes, no CEL... So far, so good - now the long haul test begins! :-lafOo.

 

[mhenon]

Still waiting on parts but here's where I'm going with the commercial pedal assembly. This is a Williams pedal that uses the bus APPS that Bob has been working with. The othe pic's show the Weather Pack connectors and how I modified my OEM wiring to accept either the Williams APPS or OEM APPS. I realized most won't want to go this route but it does bring the whole assembly, APPS and all, into the cab and out of the engine bay. If the relays (needed to make this whole thing work) prove to be a problem I'll just have to install the OEM APPS on the Williams pedal (it bolts right up) and it too will stay indoors. When the relays arrive they'll be mounted on a PC board, installed in a small project box and weather packs on the input and output sides of the board. I'll also need to bring in 5 volts and a ground to this to feed the Williams APPS and relays.

Anyway, most of the hard work has been done (thanks Bob!) and I just have to adapt this to fit my pedal assembly. If it works out I'll remove the whole OEM accelerator pedal, OEM bellcrank & APPS and be done with it.

Mike

 

[Gary - K7GLD]

Be interesting to see how it works out for you Mike - at least if it ever needs replacement, you'll be inside and out of the rain! :-laf:-laf

 

[rweis]

Cruise control cable and auto TV cable come to mind.



I have cruise and an auto so I am still trying to use the dc APPS frame bracket. Just cleanup the failure points.



Mon & Tue I am taking off to do the bus APPS, MS and get rid of the relays. I already have done the WeatherHead connectors. I still have my dc APPS and am going to convert that as well to APPS and MS. I also have a used dc APPS comming to try that and see how long it will go.



IF you need some kick a. . relays I just happen to have 4@ 50 amp relays with silver contacts (ie heavy duty), with blocking diodes (NOT resistors), and sealed for marine application. The very best quality relays I could find. Hummmm, wonder why I have those hanging around?



I am still experimenting with the string potentiometer concept. I have not dismissed that idea yet. The commercial one's are fairly large and would have to be mounted outside of the APPS frame / bracket system.



I am going to drive the APS / MS system while thinking the string potentiometer and see where that goes.



IF worse comes to worse, I can see doing a Williams APPS ($100) every 5 - 7 years or so. I do a blower to the VP44 and the blower might have some bearing on the longevity of the APPS. I am going to ventilate the APPS pocket for cooling.



Bob Weis

 

[mhenon]

Be interesting to see how it works out for you Mike - at least if it ever needs replacement, you'll be inside and out of the rain! :-laf:-laf

Yeah. . but working upside down on the drivers seat!!!

It does look pretty "Big Rig like" sitting in there. If this works the first thing I'm doing is stopping by the nearest DC dealer and telling them to check my APPS;" it feels weak. . almost no power". Just want to see their face when they open the hood and nothing's there! That would be priceless.

Mike

 

[mhenon]

. . IF worse comes to worse, I can see doing a Williams APPS ($100) every 5 - 7 years or so... Bob Weis

Even if it only goes 5 years or so it's WAAYYY cheaper than DC fix. Are you still setting a code Bob or did it clear? Have you figured out what caused it?

Mike

 

[Gary - K7GLD]

I do a blower to the VP44 and the blower might have some bearing on the longevity of the APPS. I am going to ventilate the APPS pocket for cooling.



Bob Weis

Yup - if you noticed in my earlier pic of my version of the home-made APPS, my VP-44 blower tube blows a healthy stream of cool air on both the VP-44, and into that APPS cavity:



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There's enough gap around the APPS bracket mounting surface to feel a pretty decent air stream when the blower is running - sure can't hurt! :-laf

 

[FLynes]

AH, you missed THIS part of my earlier post:







Have driven the truck several times - mostly short-haul trips, had the throttle from idle to redline - smooth as glass, no codes, no CEL... So far, so good - now the long haul test begins! :-lafOo.

You're right, I DID miss it... . wow, very impressive gentlemen! Kudos to all of you who have come up with these different solutions. Of course, this is getting written up in the TDR, right? :-laf

 

[rweis]

Mike,



If you go to the pedal, I WANT TO BE THERE WHEN YOU GO TO THE DEALERSHIP TO HAVE THE APPS CHECKED!!!!!!!!!!!!!!!!!!!!!!!!! Oo.



That is way too funny, it would be worth the airfare to see that.



I have not had a chance to tweak the IVS ECM yet. I have not reset the ECM APPS values either.



Monday & Tuesday (during the day no less, sunshine and everything!) I am going to do the ECM APPS recalibration. If that does not do it then remount the dc APPS and measure the voltage to the IVS then remount the bus APPS / relays an tweak the voltage to the ECM to match it.



If mama (ECM) ain't happy, then nobody's happy! Just tough to get to it when work 07:30 AM - 6:00 PM M-F, most nights a meeting to go to, back by 11:00 PM. Neighbors get a little goosey when I start working under the hood at midnight. I personally know all the police officers on the swing shift. Now they come by and just wave .



It drives fine. I did a couple of WOT to see what that would do, fine. I am going to pull the RV at the end of March and will get that test done then.



Bob Weis



I'm starting to think about a somewhat plug and play version on the bus APPS. You take the APPS bracket off, you swap the APPS (2 screws, no adjustment, just screw it on), plug the OEM APPS connector into a box, plug the bus APPS connector into the box. Done, crank her up.

 

[KarlC]

Just had a thought... The bus APPS has upside-down logic that pulls the lines to +5 volts instead of ground. Rather than using relays to reverse the logic, it might work to just put a resistor from each of the bus IVS lines to ground, and switch the idle and not-idle lines between the bus APPS and ECM. When the bus APPS pulls one of the lines to 5 volts the ECM would see that, and when the APPS releases the line the resistor would pull it to ground and the ECM would still be happy. I'd try 1K resistors.



I don't have a bus APPS to try it out, but if anyone else wants to...



Karl

 

[Gary - K7GLD]

OK, so guys are interested in what's developed here, but are scared or nervous about cutting up or drilling on a perfectly GOOD APPS - or even mutilating a failed one...



Can't say I blame them! :-laf



But how about a relatively easy way to head off a potential failure issue - or maybe resurrect a failed one? Going into this thread, I was convinced it was the potentiometer section that was most often failing - but now, after 4 years of muddling through all this, am now pretty sure the primary failure points are the electronics in the IVS section, and/or the pressure contact setup between the internal Mylar printed circuit and the pin connectors. The potentiometer itself seems the LEAST likely to prematurely fail!



NOW, not everyone is able or willing to cut their APPS apart to do as I pictured earlier in this thread - but what if you could easily and inexpensively eliminate ALL the IVS circuitry, and HALF of those pressure contacts?



And ALL without cutting or drilling - as close to plug-and-play as possible?



Here's what I played around with this morning. The hardest part of potentially extending the life of a good APPS module, is converting to a microswitch IVS - but the bracketry fabricating for the MS is a bottleneck, getting it properly fabricated, then mounted on the OEM APPS properly to allow easy installation and adjustment of the MS.



Here's what I made up as a demo piece:



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I used a small section cut from a common U-bolt/muffler clamp piece, one where the backing piece was nearly the same width as the APPS idle-side stop post, then welded on a piece of steel strap material for the MS mounting platform.



Here's a shot of the piece itself:



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And here it is mounted to the APPS idle stop post, after drilling the piece and installing a setscrew



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The MS shown is there just for display purposes - but you get the idea, a simple clamp-on part that is easily installed, and provides easy MS adjustment in relation to the APPS belcrank.



Now, the last piece of this particular approach, is to obtain an APPS module jumper cable that allows insertion between the module and the harness to the ECM - the harness end plugs are available here:



http://www.deutschconnector.com/cgi-bin/store/agora. cgi?cart_id=289777. 6852*_Z7-N2&xm=on&product=DT_6-Contact|DT_Sealing_Plug|Mounting_Accessories



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And are easily wired so that only the OEM APPS module potentiometer is used - 3 of the 6 contacts in that module. The other 3 wires would come from the MS installed on the bracket seen earlier - the leads from the MS can easily be routed down on the lower side of the APPS bracket to where the APPS module is normally connected.



All quick and easy, and requires NO mutilation of ANY of the APPS bracket or module, or the existing OEM harness. All the OEM APPS module adjustments remain the same, and only minor setup and adjustment of the added MS. The noise filter is also easy to make up, and only costs pennies - and MIGHT not be needed at all.



The remaining trick is to fabricate the MS piece - but THAT is virtually the ONLY mechanical fabrication needed - the wiring itself is a snap!



You want "Plug And Play"? It won't get much easier than this! :-laf

 

[timbo]

Okay, so with the finished product, are the CELs staying off?

APPS conversion is working great! No CEL light or problems! I drive 18 miles through stop and go traffic and always been unhappy with being unable to lug it in 4th and 5th like a 12v. Mine would always buck below 1200RPM in 4th and 5th, Now i can run it down to 1000 in 4th and 1100 in fifth Oo.

 

[mhenon]

APPS conversion is working great! No CEL light or problems! I drive 18 miles through stop and go traffic and always been unhappy with being unable to lug it in 4th and 5th like a 12v. Mine would always buck below 1200RPM in 4th and 5th, Now i can run it down to 1000 in 4th and 1100 in fifth Oo.

timbo, you gotta be kidding. . there's a performance bonus with a different APPS!!! This would be something!

 

[FLynes]

... Now i can run it down to 1000 in 4th and 1100 in fifth Oo.

Tim, no BS here, I can do that in my truck, and it's stock.

 

[Gary - K7GLD]

Tim, no BS here, I can do that in my truck, and it's stock.

YUP - same here with mine - never had a problem lugging down smoothly, in fact, had to watch to keep FROM it, especially when towing...

 

[timbo]

NO BS! I discovered this added bonus on wed. and was very happy with the discovery,especially today in the Friday traffic. I guess my DC APPS was not in such good health after all!