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

[rweis]

The 86 Mustang 5. 0 TPS =



TH18 from manufacturer Standard Ignition (my parts guy gets $32 for it)



I will have one tommorrow and I have a bracket form Gary and will report back on fittment and mounting in the existing 2nd gen bracket before I take the time to actually mount it in place.



Then I have to go back and read the wiring arrangement again (or if timbo could restate the final wiring solution it would help )



And then we should have all the info I think (mounting fittment in existing bracket, I have the WeatherHead connectors, and will mount it in place permanently). My existing TPS works fine and I will keep that as a backup.



Then we can start getting cycle counts on it to see how it will do over a long time frame.



Do you want me to use the IVS on the TH18?, or build a universal relay switching for the IVS?



Anyone could use the relay switching, but it would be more "stuff". The TH18 IVS may not last as long as relay switching but it would be less "stuff", ie more of a plug and play.



Bob Weis

 

[Gary - K7GLD]

If I am successful in obtaining another APPS bracket, I plan on using the (apparently) easy to obtain and relatively inexpensive Ford Mustang part for the resistance function, and a separate microswitch/bracket assembly to operate off the throttle belcrank assembly, with included means for precise adjustment of IVS threshold. That should make for easily replacement of the Ford TPS unit independant from the MS, and vice versa. Doing it that way should make it as easily used by the automatic transmission guys as well as the 6-speed guys...



Looking at the mechanics of the belcrank area, fabricating an IVS adapter bracket for the MS looks to be pretty easy:



#ad




Trickiest issue is getting a neat adapter cable with proper matching plug ends to the DC OEM APPS harness connector. I have a couple of used APPS modules that I can canabilize for my own test setup, but other guys probably won't be that lucky...

 

[rweis]

Gary,



I am using WeatherHead 3 position connectors. They are pretty universal in the auto industry and can be gotten at any auto parts supply. They seal well, fit tight, and lock. They are in a lot of the connector that DC uses MAP comes to mind.



They come in already assembled connectors or in connector components so guys that would rather not build the connector can get the already assembled one. Then they have to put a butt connector on to get it into the ECM harness.



I am going to use a male end for the TPS to the ECM harness (the bracket TPS would have the corresponding female end) and a female end for the IVS to the ECM harness (the bracket IVS would have the corresponding male end) so as to not plug the wrong plug into the wrong connector.



Just an idea for connectors. I wonder if they (WeatherHead connectors) come in colors?



Bob Weis

 

[Gary - K7GLD]

Thanks Bob - I'll check out NAPA for what they have.



Also, one of the TDR members has promised that a APPS bracket is on it's way to me, so once it shows up, I can get started. I just placed an order for a couple of the neat roller actuated microswitches pointed to earlier in this thread:



Microswitch: 5A, Lever Actuator w/ Roller



My goal is as nearly a "factory look and function" as possible, with ease of duplication and replacement of components also as easy as possible. :-laf

 

[mhenon]

Info on Weather Pack connectors:

Weather Pack – Components and Tools for the Weather Pack System

I've already cut my OEM wiring harness and installed Weather Packs on the engine side of the harness and OEM 6 pin connector side. I did this to facilitate the Williams Commercial Bus TPS that Bob and I bought (it uses Weatherpacks). But. . I can go right back to the OEM APPS , if needed, in less than a minute.

As Bob said above. . they're fairly common in the auto industry and easy to find at your local NAPA store.

Mike

 

[timbo]

Here is a pic of the ford TPS with the scale placed to show bolt center. I measured it with the caliper it's 1. 300 center to center and the hole on the right is slightly slotted. The wiring on the ford tps is as follows

orange=5v+

black = ground

green . 5-4. 5 back to ECM

The wiring is the same as discussed earlier, the fac. plug is numbered and that relates to the schematic except the schematic is showing the IVS in the accel position.

 

[Gary - K7GLD]

Here is a pic of the ford TPS with the scale placed to show bolt center. I measured it with the caliper it's 1. 300 center to center and the hole on the right is slightly slotted. The wiring on the ford tps is as follows

orange=5v+

black = ground

green . 5-4. 5 back to ECM

The wiring is the same as discussed earlier, the fac. plug is numbered and that relates to the schematic except the schematic is showing the IVS in the accel position.

HOOoookay, the DC APPS is 1 3/4 inches center to center for mounting holes, then the issue of mating the Ford unit to properly index and engage the DC APPS mounting plate and linkage - while at the same time providing the same degrees of operational rotation from idle to WOT...



If all else fails, I still can probably adapt the Ford unit to one of my used DC APPS modules as purely a base mounting platform, as long as the degrees of rotation are the same...



If not, I'll have to rethink the use of the Ford unit...

 

[rweis]

If it were easy, then anyone could do it!



There are several guys on TDR that can make up a bracket and reproduce it accurately.



I still vote for the cummins bus APPS, or the Ford APPS with a bracket, over what we have.



Bob Weis

 

[rweis]

Just looking at micro switches in Mouser catalog.



Would the switch body type that mounts in a standard mounting hole be an idea? Thinking being that you could very accurately adjust the nuts that hold the threaded body of the switch to meet the APPS rotating arm. Some of the plunger type of bodies also have dust caps on the plunger.



Just some ideas after we get the prototyping done.



Bob Weis

 

[JHansen]

Hey guys-better late to the party than not arriving at all... . :-laf



I am not an electrical guru-but reasonably decent at running down parts. Never occurred to me until right now to look at this thread. I dug out my Cummins ISB troubleshooting book to see if it had a listing for the connectors. They list the APPS plug as a Deutsch DT series-lo and behold, with the use of Google, came up with this: Deutsch DT Series 6-Way Connectors which looks very familiar to me anyways. I know they are-or were-out there as Gordon from Practical Solutions used to make a high idler that plugged right in between the APPS and harness.



Hope this is of assistance-I will keep following this thread to hopefully see a resolution-as I have a dead one sitting patiently in my box of goodies waiting for a resolution.



Jason

 

[mhenon]

I think that's our connector. Thanks Jason.

 

[KarlC]

They list the APPS plug as a Deutsch DT series-lo and behold, with the use of Google, came up with this: Deutsch DT Series 6-Way Connectors which looks very familiar to me anyways. I know they are-or were-out there as Gordon from Practical Solutions used to make a high idler that plugged right in between the APPS and harness.

Jason, that's great! Oo. Thanks a bunch for finding this. I want to build a high idler myself and this should get me going on that. Of course I'll let you guys know how it goes, w/ schematics etc.

 

[mhenon]

Here's something interesting. As my wife and I are on the road visiting the kids I haven't been able to get my hands dirty on this project. Kinda feeling like a bump on a log! Just got wondering what type of TPS the Jetta has. I mean it is a diesel and all.

The TPS on the Jetta is located in the cab and part of the pedal assembly (very much like the commercial Williams bus pedal assembly). Got looking at the sensor part of it and guess what..... 6 wires coming from the TPS. Now if three of those wires are used for the potentiometer. . I wonder what the other three are for???????? OK. . I'll take a wild guess... AN IDLE VALIDATION SWITCH??

I'm trying to dig up a schematic for the Jetta TPS to verify this but no luck so far. The TPS looks very well built and (get this) it's servicable. Five cover screws allow access to the potentiometer/cicuit board. The quality of this unit is just obvious and very few folks report problems with it. Mine has been in service for over 100K miles.

Can't see any way to adapt this TPS to the OEM bellcrank. You would have to use the pedal assembly as a whole to make it work but that could be an option. Found the whole asembly on eBay for $180. 00 bucks. Interesting!

Mike

 

[rweis]

Well, some good, some not so good



Prelimimary measurements:



DC APPS frame in about 45* of rotation



Ford APPS . 3k - 3. 5k BUT in about 110* of rotation:::I think the right amount of ohms but too much rotation



Bus APPS . 257k - 2. 08k in about 45* of rotation:::the right amount of rotation but too few ohms



I think what we found is the need to have 3. 5k in 45* of rotation.



After work today I will try to measure the DC APPS ohms and see exactely what DC did in ohms as we know the rotation from the APPS frame.



We can't just keep guessing this APPS or that APPS (are the ohms per rotation angle right?, is the mechanical fittment right?, etc). The string potentiometer is looking better and better. We would know in advance the total rotation angle and the total ohms and could pick one that would give us 3. 5k for 45* of rotation. Something to think about.



Bob Weis

 

[rweis]

Is the procedure where you depress the pedal 3 times a procedure that would take into account the resistance differences with different APPS????



If so then the bus APPS that fits perfectly but only goes to 2. 08k might actually work the whole pedal range, AND work compatiably.



Thoughts?



Bob Weis

 

[JHansen]

Glad to be of some minor assistance... .

 

[mhenon]

Is the procedure where you depress the pedal 3 times a procedure that would take into account the resistance differences with different APPS????



If so then the bus APPS that fits perfectly but only goes to 2. 08k might actually work the whole pedal range, AND work compatiably.



Thoughts?



Bob Weis

Bob, I think that's right. The variation even in the same type of APPS is pretty large. The ECM should figure out what range it has to work with once the learning process is over.

Still think that Williams TPS is a good bet and better built too. Having said that I'm sure there are several TPS out there that "would" work if we wanted to push the issue. I am a little surprised that the Williams TPS doesn't seem to have enough resistance. My initial test looked like it had too much but I didn't have much time to play with it. Good luck.

Mike

 

[KarlC]

Is the procedure where you depress the pedal 3 times a procedure that would take into account the resistance differences with different APPS????



If so then the bus APPS that fits perfectly but only goes to 2. 08k might actually work the whole pedal range, AND work compatiably.



Thoughts?

I think it will work just fine. I don't think the resistance of the APPS is all that critical. And the important part of the resistance is the end-to-end resistance of the APPS, measured from pin 4 to pin 5. As a guess, resistances between 1k and 10k ohms would probably work.



I think what is more important is the voltage from the APPS to the ECM. With the key on, the APPS resistance element has 5 volts on one end and 0 volts on the other. The wiper is grabbing a voltage from a point part way along the element, and of course that point changes with throttle setting. The voltage will be somewhere between 0 and 5 volts, as the wiper goes from one end to the other end of its travel along the element. They've put in mechanical stops in the APPS to limit the extent of wiper travel so it can't ever get to 0% or 100%, and the stops on the bellcrank limit the travel to even less.



If the APPS idle calibration setting is 0. 620 volts, mechanically the wiper will be 12. 4% (0. 62V divided by 5V) of the way up the resistance element at the idle end of the bellcrank's travel. I don't know what percentage it goes to at WOT, but a key-on measurement of the voltage at pin 3 under WOT would tell us. I'll try to make the measurement this weekend.



The learning process makes up for some variation in this, but I don't know how much.

 

[Gary - K7GLD]

Is the procedure where you depress the pedal 3 times a procedure that would take into account the resistance differences with different APPS????



If so then the bus APPS that fits perfectly but only goes to 2. 08k might actually work the whole pedal range, AND work compatiably.



Thoughts?



Bob Weis

Dunno, but will be interesting to see, if anyone actually tries it!



And Scottlauer has sent me a APPS bracket for my own variety of experimenting - should be here first of the week. We traveled over to Payette yesterday to visit my Dad - and when we passed thru Ontario where there's a Dodge dealership, tried their service department to see if there were any castoff APPS brackets laying around, and got the same story as another poster to this thread mentioned - they either return the warranty ones to DC, or toss them - but the lady service writer seemed quite friendly, so I got the impression they would have no problem giving one out if it was available. Obviously, that will vary from one dealer to another, but it might be worth checking for guys interested...

 

[timbo]

I just wanted to thank Brad patterson for donating an apps bracket, he even paid shipping and to top that off he 2nd dayed to me!! Got it today, and right now i'm doing some brainstorming. Thanks again. Also thanks to everyone involved in this thread, it was definitely a motivation for me!