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

[rweis]

The bus APPS is somewhat different.



On the frame of the APPS is a 6 pin connector female,



then a 6 pin connector male plugs into that,



then that cable comes about 2' and splits out into 2 WeatherHead connectors.



1 WeatherHead connector services the APPS resistance pot,



the other WeatherHead connector services the IVS function.



I'll take a pic and figuer out how to post it (I need to learn how to do that anyway).



Of course the connector at the APPS frame may be the same construction (I hope not, but I am not willing to destroy a new bus APPS to find out. ).



Bob Weis

 

[Gary - K7GLD]

OK, here's a very ROUGH idea of where I'm headed - the actual, and higher quality microswitch I have ordered won't be here until the first of next week - so this shows the MS placement using another similar MS - actual bracket can't be made until the real MS to be used arrives, but this shows general placement and position:



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The same is true of the rotary pot seen above, the difficulty with that pot, is converting the linear motion of the belcrank to the rotary, and larger travel needed for the pot - but that IS the actual precision pot that will likely be used.



Below is an available option, using an in-line pot - it would be easier to use, since it's normal travel is in a line much like what the APPS belcrank provides, but is not as quality a unit as the rotary previously seen:



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Method of connecting either pot to the belcrank, will be either a chord of appropriate type, or a small diameter stainless steel line, such as used for fish line leader material - and with an appropriate return spring to maintain line tension and assure return of the pot to an idle position. There are other issues, such as installing the above components, while providing access to APPS bracket mounting bolts, and also allowance for the added linkage for the auto transmission hardware - but we'll get there!



Like I said, a rough idea, but all I can do until the final pieces arrive - meanwhile, I'll play around a bit with the dissected APPS unit shown further above...

 

[Gary - K7GLD]

A bit of a potential issue arises - looking at the pic Bob sent me of his automatic transmission APPS bracket, and comparing to mine seen further above, the additional cables caused by the A/T kickdown, etc. , really intrudes into the area where I would prefer to locate whatever potentiometer I end up using - in fact, the bracket and lash up on my own 6-speed truck uses ONLY the single larger throttle rod seen, and there's not even an opening provided in either of the brackets I have for that lower A/T cable:



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That makes it sorta hard to develop a "one size fits all" APPS replacement that will apply to both transmission types...



THAT being the case, I may end up having to just focus upon my own setup, which I have the bracket and related items for, and leave it to Bob or another member involved here (assuming I actually get my own approach working!) to develop a similar setup for the A/T trucks, using their own specific brackets as the pattern...

 

[rweis]

Gary,



IF I remember correctly (CRS) the IVS happens slightly after / before the idle stop, something like 1100 rpm. I could be wrong here, but that is what I remember (and someone needs to validate this info).



The reason I bring this up is your IVS mounted in the same geometric plane as the bell crank can only activate at the idle stop or very very close. If it tried to operate 200+ rpm from the idle stop it would block the bell crank from achieving idle.



Maybe I got some information screwed up somewhere.



That is one of the reasons the mount of the MS I'm thinking of has the MS perpendicular to the bell crank so the bell crank can go toward idle, force the MS roller UNDER the bell crank (activating the IVS), and still allow the bell crank to go to the idle stop while the MS roller rolls on the under side of the bell crank in the activated mode.



When the bell crank goes from idle toward throttle the roller on the MS rolls on the under side (idle activated) until the bell crank is at 1100 rpm then the roller clears the bell crank edge and activates the throttle mode of the IVS.



IF



The IVS (throttle mode) can activate as soon as the bell crank starts to move, then the edge mount should work fine and a much much simpler mounting can be done.



The delay in the IVS activation is why my MS mounting is perpendicular to the bell crank and much more complicated so the MS roller can roll under the bell crank after activation.



Bob Weis

 

[rweis]

I was wondering where the pot was going to go on an auto transmission APPS.



IF it turns out needing a pot and you have a auto transmission I think the pot has to be where the APPS module is right now. That would also drive the pot to being a direct drive pot.



A direct drive pot then let the bell crank shaft drive the pot and design a way to hold the pot in place letting the bell crank shaft drive it like the bell crank drives the dc APPS (like P3America.com MP20IP, has a better temp range (-25*C (-13*F) - 85*C (185*F)) but maybe not good enough temp range).



The key to the pot I think is finding a pot that will go from 400 ohms to 2400 ohms in the approx 48* of rotation of the bell crank. The MP20IP I think will do about 1500 ohms for the 48* (400 ohms - 1900 ohms), maybe not quite enough.



I got the values by dividing the 320* rotation of the MP20IP by 48* (min as suggested on page 6 of the SAE J1843) giving 6. 66:1 or 15% of rotation. The 10k version of the MP20IP would give 1500 ohm range. Index the MP20IP to start at 400 ohms and it would go to 1900 ohms.



Now IF the rotation of the Bell crank is 54* (max as suggested on page 6 of the SAE J1843) then:

320*/54* giving 5. 93:1 or 16. 9% of rotation. 10K version of the MP20IP would give 1690 ohms. Index the MP20IP to start at 400 ohms and 54* later you have 2090 ohms which should work.



Either way I think a MS and a direct drive pot should totally rebuild the dc APPS. I do not know the price of the MP20IP. They do not answer the phone at 1:35 A. M.



Bob Weis

 

[Gary - K7GLD]

Gary,



IF I remember correctly (CRS) the IVS happens slightly after / before the idle stop, something like 1100 rpm. I could be wrong here, but that is what I remember (and someone needs to validate this info).



The reason I bring this up is your IVS mounted in the same geometric plane as the bell crank can only activate at the idle stop or very very close. If it tried to operate 200+ rpm from the idle stop it would block the bell crank from achieving idle.

I'm sure you are correct - the question is, will the natural operational movement required by the MS between off and on meet the design program to allow the ECM to make the transition from idle to off-idle? I'm thinking it will - but since nothings sacred here, there's no reason a suitable ramp can't be ground/filed into the belcrank rim to allow a suitable rotation vs switching application.



And yes, the problem developing a single solution that will fit both manual and automatic transmission trucks is what I commented upon in my earlier post - and since there is needed specific trial and testing t hat can ONLY be done with the A/T trucks, I probably can't work properly in that area, and guys like you who DO have A/T trucks will probably have to address those specific issues.

 

[rweis]

Oo. Oo. Houston WE HAVE A SOLUTION Oo. Oo.



Bus APPS works fine if its output drives relays Oo. Oo.



Also need a 100 ohm resistor in the APPS pot leg to get the ohms up to 350 or so Oo. Oo.



Engine accelerates fine, relays can be felt functioning. Oo. Oo.



Test drive later



Bob Weis

 

[JAG1]

Once you guys get this figured out for an automatic trans too, could you explain how a laymen (greenie) like me can understand how to do this? Or would it be too much reiteration?

I'm willing to pay for a kit if one gets put together with instructions.

Thank you for sharing all the continueing information/ updates.

 

[timbo]

Congrats Bob, good job!!!! I also just got mine done and on the truck all works GREAT. Smooth as silk. Oo. Oo. Looks like a standard 3 wire TPS and Microswitch works fine. Here's some pics of the finished product.

 

[rweis]

Well, thats COOL! Two solutions in the same day!



Your MS also validates the way Gary is doing his MS. I think he is going to use his dc APPS and the MS. Could have three solutions.



I was leary of not having the idle IVS and the throttle IVS at the same place (bell crank position), but you seem to have removed that problem.



I do have a MIL about the idle and throttle validation voltage being too low. I have not reset my APPS yet and that is probably what it is, or I need to bring the IVS voltage up a tad.



I think the simplist solution and most cost effective solution will be Gary's if he uses the dc APPS for the pot and only changes the IVS.



Then yours is next except for the machining needed to be done to get the Mustang APPS to fit. If someone (if Gary goes for changing the pot) will take a dc APPS and do the MS then that is probably the best solution.



Mine comes in last. The bus APPS was $100 and the relays and sockets were $20 each set (2 sets) for a total of $140. Mine does not require any physical changes to the APPS bracket, but there are some wire changes. I will make up a check list of what the wire changes were and why each change. I also think you should change the relays each year.



Can anyone do it? Sure.



If you can put the MS in, I would do that approach first and see how it goes. If you are not mechanical at all,

then,

If you can not put the MS in (not mechanical at all), then I would do the bus APPS as it is all soldering and wire cutting.

then,

If you can not cut wire and solder you need to find someone to do one of the above options.



I think given some time I could make the bus APPS a remove and replace harness, but I would have to get some of the dc female sockets so you could unplug the dc APPS and plug in the other harness, but you would still have to change the APPS pot itself.



Anyway, we need to drive the new configurations for a couple of weeks to be sure they work under all circumstances (and I need to reset the ECM APPS values to clear the MIL, or adjust the resistance values a little on the IVS)



Bob Weis

 

[rweis]

timbo,



How did you mount the MS?, particularly the block it is mounted to.



Bob Weis

 

[timbo]

timbo,



How did you mount the MS?, particularly the block it is mounted to.



Bob Weis

It is just a 1/4 thick alum tapped to mount the switch and a #10-32 screw to mount the alum peice. I drilled and tapped the bellcrank for the 10-32 screw.

 

[Gary - K7GLD]

For lack of anything better to do until my MS and adaptor plug arrive in the next day or so, I played around with one of the in line pots to see what I could do with them - here's the individual parts:



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And here they are just laid in place - the pot/belcrank setup works nice and smooth - this lashup delivers about 1500 ohms resistance swing, which I think would work, after padding each end to provide about 2500 ohms total resistance - the pot itself is a bit over 2K...



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Best part of this method is, it's relatively easy to fabricate, uses a positive and direct straight line actuating motion, and is easy to assemble and test.



As to also testing the use of the pot section of the used APPS I showed earlier, I verified that the connections are easily soldered, both the membrane traces as well as the pin stubs, so will play around with that approach too, as soon as the MS arrives that I would use to replace the DC APPS IVS electronic switch...

 

[rweis]

Test drive this morning 17 miles to work. All is well, functioned as expected. Still have to register the new APPS or adjust the IVS voltages.



One of the major disadvantages withthe bus APPS is it needs 5 volts to function the IVS. The dc APPS uses ground to function the IVS. You have to build a 2 relay package (1 for the IDLE IVS, 1 fro the THROTTLE IVS) to get the 5 volt switching to switch ground instead for the dc ECM. Before we glob onto the bus APPS we need to look for a good mechanical fit that uses ground for the IVS function like the Mustang IVS does. The set of relays add another failure component set to the equation that we do not need more complication, we need less complication.



Bob Weis

 

[Gary - K7GLD]

I haven't looked closely at the fittings or method used to physically remove the throttle rod mechanism from the APPS bracket, and since I will likely have to do that a few times while experimenting with different APPS lashups, want to do as little damage as possible to those plastic mount fittings, so what's the recommended tool or method?

 

[rweis]

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



Bob Weis

 

[mhenon]

Test drive this morning 17 miles to work. All is well, functioned as expected. Still have to register the new APPS or adjust the IVS voltages.



One of the major disadvantages withthe bus APPS is it needs 5 volts to function the IVS. The dc APPS uses ground to function the IVS. You have to build a 2 relay package (1 for the IDLE IVS, 1 fro the THROTTLE IVS) to get the 5 volt switching to switch ground instead for the dc ECM. Before we glob onto the bus APPS we need to look for a good mechanical fit that uses ground for the IVS function like the Mustang IVS does. The set of relays add another failure component set to the equation that we do not need more complication, we need less complication.



Bob Weis

Nice work Bob! I sorta envisioned this seperate 3 wire IVS system to plug into a small box (like a chip) that housed the micro-switches and additional 5 volt line. With weather packs on both sides of the box it would become a plug and play with the Williams APPS.

What relays did you end up using and where did you tap the 5 volts? Should we be testing any other relay or doesn't it matter that much? It would be nice if we designed things so changing/replacing relays was fairly simple. If they're something that might fail. . keeping a few spares in the glovebox would be handy.

Anyway, glad you got it working.

Mike

 

[mhenon]

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



Bob Weis

A heat gun wouldn't hurt either.

Mike

 

[rweis]

The relays are very garden variety and you can get them anywhere, any auto parts store of any kind. I have them in my headlights, lp, transmission cooler, a lot of places.



They are very easily replaced, and are fairly cheap ($10 each). I normally change all mine out once a year. In this application we are dealing with computer level voltages and amperages so they should last a very long time. The relays have a diode across the coil for voltage spikes.



If the relay fails the APPS fails so it is important that they work.



I tapped the 5 volts off the APPS pot 5 volts. In the bus APPS all the lines are in the same unsplit factory loom. I went in at the entrance of the loom and soldered the two lines together and insulated them from anything else and then wrapped them (2) in their own split loom, and put that inside the factory unsplit loom.



Bob Weis

 

[mhenon]

I was looking at 5 volt Reed relays from Digi-Key. These come with a diode in the circuit to prevent voltage spikes from going back through the system (the ECM in our case) and are fast switching relays. i'm not exactly sure what we should be looking for here. Maybe someone could comment on what might be the best relay for this application. Here's what I found from Digi-Key:

RELAY REED SIP SPST 5V W/DIODE - HE3621A0510

Mike