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

[mhenon]

timbo... It sounds like the ECM had not yet learned where IVS settings were (how could it in this case). That's the purpose of the "key. . pedal slowly to the floor and back" proceedure after installing a new APPS.

Soo... after a few attempts at trying to learn the right voltage for "idle" and "accelerate". . it gave up, went to idle and sent a fault code.

If you could rig that microswitch to the bellcrank somehow so it would switch on and off at a consistant position it might work.

Gary... A TDR member has sent my a bad APPS (APPS only. . no housing). I'll be on the road for a few more weeks but if you still need one when we return you can have it. I'll let you know when we get home.

Mike

 

[KarlC]

I think the IVS contacts should be reversed from what you're describing. From tracing the APPS schematic and from testing Rick's APPS I think the idle contact should be between between pins 6 & 1, and the off-idle contact between pins 2 & 1.



From the 2001 manual the schematic on page 8W-30-30 shows both contacts closed, not the usual normally-open and normally-closed contacts. This is confusing to me. The contact that goes to pin 6 is labeled "1" and the contact that goes to pin 2 is labeled "2". Then there's wording along side that says

1 idle

2 not idle

I'm thinking from this that contact #1 (which goes to pin 6) should be closed at idle, and contact #2 (which goes to pin 2) should be closed when not idling.



What do you guys think? Mike, when you get a chance what about reversing the contacts and see what happens?



It's possible the ECM doesn't throw a code and run it back to idle until it sees a TPS vs IVS discrepancy a few times, to avoid false alarms.

 

[rweis]

If the Ford APPS works out what is the cost, and what is the description we would tell the Ford parts counter man.



A comment about the fitment to the APPS bracket would be nice, maybe I missed that somewhere?



Bob Weis

 

[Gary - K7GLD]

Gary... A TDR member has sent my a bad APPS (APPS only. . no housing). I'll be on the road for a few more weeks but if you still need one when we return you can have it. I'll let you know when we get home.

Mike

Thanks for the offer Mike, but I already have a pair of used APPS units - it's the bracket I particularly need, and hopefully one that still has the APPS itself still in place, so I can get a reference resistance range as a baseline.



I sent the one APPS bracket I had to Bob Weis for his experimenting, and he has offered to return it, but I prefer that he keep it and continue with his own experiments - the more fronts we address in testing, the better our chance of a better solution than DC has provided...

 

[timbo]

If the Ford APPS works out what is the cost, and what is the description we would tell the Ford parts counter man.



A comment about the fitment to the APPS bracket would be nice, maybe I missed that somewhere?



Bob Weis

The TPS is from an 86-93 mustang ,in stock, at advance auto for $32. 98,or at any corner junk yard for next to nothing. As far as fitment it looks alittle smaller than DC APPS,maybe, but i can't tell. I have not even pulled the cover off mine,so i cant say it's an exact fit. My APPS is complety fine At this time so i don't want to disturb it. I am a machinist so i'm not to worried about making it fit. Right now i'm just trying to make it work as a separate assembly. If I can make it work I will adapt it to stock bracket assembly.

 

[timbo]

Well i mounted the M. S. to a stock mustang throttle body so the TPS voltage was . 56@ idle pos. and the M. S. kicked@. 6. I then did the LEARN process 3 times just to make sure the CEL light did not come on. It did not. So i Fired it up! It WORKES!!Oo. Oo. Oo. Oo. Oo. I reved it up and down for several minutes and held it at a given RPM for awhile and it WORKS!!Oo. Oo. I then shut it off and checked for codes. NO CODES!Oo. Oo. I made a movie of part of it but i'm having trouble uploading it. Soon you all will see it for yourselves!

 

[Gary - K7GLD]

Well i mounted the M. S. to a stock mustang throttle body so the TPS voltage was . 56@ idle pos. and the M. S. kicked@. 6. I then did the LEARN process 3 times just to make sure the CEL light did not come on. It did not. So i Fired it up! It WORKES!!Oo. I reved it up and down for several minutes and held it at a given RPM for awhile and it WORKS! I then shut it off and checked for codes. NO CODES!Oo. Oo. I made a movie of part of it but i'm having trouble uploading it. Soon you all will see it for yourselves!

SUPER! Congratulations on being the FIRST to develop and install a WORKING SOLUTION to the weak DC APPS unit! Oo. Oo. Oo.



SO, since there was an earlier question regarding proper IVS idle/off idle pins, which pair did you find worked properly?



If the Ford unit checks out as a easy and satisfactory physical replacement for the DC APPS, needing only addition of an external manual switching IVS, that may be far easier than engineering a whole new APPS resistance unit... Oo.

 

[timbo]

SUPER! Congratulations on being the FIRST to develop and install a WORKING SOLUTION to the weak DC APPS unit! Oo. Oo. Oo.



SO, since there was an earlier question regarding proper IVS idle/off idle pins, which pair did you find worked properly?



If the Ford unit checks out as a easy and satisfactory physical replacement for the DC APPS, needing only addition of an external manual switching IVS, that may be far easier than engineering a whole new APPS resistance unit... Oo.

Like i hooked it up the first time. #1 and #2 closed in idle position. 1and 6 accel pos.

 

[mhenon]

Well i mounted the M. S. to a stock mustang throttle body so the TPS voltage was . 56@ idle pos. and the M. S. kicked@. 6. I then did the LEARN process 3 times just to make sure the CEL light did not come on. It did not. So i Fired it up! It WORKES!!Oo. Oo. Oo. Oo. Oo. I reved it up and down for several minutes and held it at a given RPM for awhile and it WORKS!!Oo. Oo. I then shut it off and checked for codes. NO CODES!Oo. Oo. I made a movie of part of it but i'm having trouble uploading it. Soon you all will see it for yourselves!

timbo... That's great! I suspected something like this all along (that our APPS wasn't that special) and you just proved it.

So now there's another solution to the APPS; install a lever actuated microswitch similar to this: "http://www.hobbyengineering.com/H1883.html" to operate the IVS. THEN... . run down to your local NAPA and purchase any one of a number of cheap TPS that fit the bellcrank and you're good to go.

Now we just have to work out the fine details of which TPS and microswitches work best for a quick easy install. Also since we're talking about slicing the OEM wiring and running 3 wires to the TPS and 3 wires to the IVS I would recommend the Weather Packs on the wiring harness side. They're easy to find (NAPA again) and pretty rugged. If there's a common 3 prong plug that fits more than one TPS. . that would be handy too.

Anyway. . looks like we're on our way to putting this thing to rest.

Mike

 

[KarlC]

Well i mounted the M. S. to a stock mustang throttle body so the TPS voltage was . 56@ idle pos. and the M. S. kicked@. 6. I then did the LEARN process 3 times just to make sure the CEL light did not come on. It did not. So i Fired it up! It WORKES!!Oo. Oo. Oo. Oo. Oo. I reved it up and down for several minutes and held it at a given RPM for awhile and it WORKS!!Oo. Oo. I then shut it off and checked for codes. NO CODES!Oo. Oo.

Hey, that's fantastic... Great job!! Oo. That'll give a lot of people some options. This might be an opportunity for someone to make a few bucks selling a kit to fix broken APPSes. Wonder if I have the wiring backwards or if the the LEARN process makes up for it. Doesn't matter any more.

 

[rweis]

Ahhhhh, cool!



I would suggest a couple of us do this (some auto, some stick) to see how universal it is. Different guys have different driving habits (cruise control, different years, TV cable to auto transmission, doing an actual wot run, different engine setups, etc) and test it from several different angles.



I constantly find it totally amazing that a bunch of TDR guys can get their heads together and solve seemingly UNsolvable problems! with little more than screw drivers and wrenches and late night online discussions.



Bob Weis



I will get the Ford TPS and compare it to the cummins bus TPS to see how similar they are in range and rotation resistance and fitment since I have Gary's extra bracket.

 

[timbo]

Anybody interested in selling me an old APPS assembly? I don't need the sensor i need the bracket -bellcrank assembly,so i can modify it and actually test it under driving conditions. It will be a direct replacement with the mating factory plug!

 

[Gary - K7GLD]

Anybody interested in selling me an old APPS assembly? I don't need the sensor i need the bracket -bellcrank assembly,so i can modify it and actually test it under driving conditions. It will be a direct replacement with the mating factory plug!

You might try a local DC Dealership service department - I suspect they just toss the replaced ones, and might have one or more just laying around. I would do the same, but the nearest DC dealership is a 150 mile round trip, and pretty small at that, so pretty slim chance they would, or could, supply one.



One of the TDR members from this thread has offered me a spare he has, and I'm sure there are others here who have had to replace their APPS assembly, and would also donate one to the cause at minimal expense.

 

[timbo]

You might try a local DC Dealership service department - I suspect they just toss the replaced ones, and might have one or more just laying around. I would do the same, but the nearest DC dealership is a 150 mile round trip, and pretty small at that, so pretty slim chance they would, or could, supply one.



One of the TDR members from this thread has offered me a spare he has, and I'm sure there are others here who have had to replace their APPS assembly, and would also donate one to the cause at minimal expense.

Well Gary i called 3 dealers and 1 said they rarely replace the APPS, the other 2 said "If it's a warr. deal they send them back to dodge,if not they throw them in the garbage and they will not give them away nor will they sell them"#@$%! I was just reminded of why i hate dealers! Anyway i was able to get the little movie clip up YouTube - TPS experiment

 

[Gary - K7GLD]

Well Gary i called 3 dealers and 1 said they rarely replace the APPS, the other 2 said "If it's a warr. deal they send them back to dodge,if not they throw them in the garbage and they will not give them away nor will they sell them"#@$%! I was just reminded of why i hate dealers! Anyway i was able to get the little movie clip up YouTube - TPS experiment

I'll check out the movie clip in a bit, but in case it doesn't show up well, can you post a pic of the Mustang TPS, perhaps with a ruler alongside for size?

 

[rweis]

I called my local parts house to get one of the Ford APPS and apparently there are several in the 86-93 Mustang years based on engine size, year etc. Can someone list the Ford part # or the engine size (ie 2. 3, 3. 8, 5. 0) or a part number?



I know zero about a Mustang so there is something I probably do not know that would have narowed down the choices.



Bob Weis

 

[Gary - K7GLD]

I called my local parts house to get one of the Ford APPS and apparently there are several in the 86-93 Mustang years based on engine size, year etc. Can someone list the Ford part # or the engine size (ie 2. 3, 3. 8, 5. 0) or a part number?



I know zero about a Mustang so there is something I probably do not know that would have narowed down the choices.



Bob Weis

Yup - me too!



Got a look at the video, but too dark to really make anything out well - sounded good tho'!

 

[timbo]

I used the one from my 86, 5. 0. Mine's not quite stock though

 

[timbo]

Sorry the movie was dark but i was trying to actuate the throttle and hold the camera at the same time. When i get home i will take a pic. of the tps beside a ruler.

 

[mhenon]

timbo. . is that a 3 pin TPS? If so (and I'm guessing it is) it doesn't matter which TPS anyone wants to toy with. They'll all work with a SPDT relay to trigger the IVS.

Did you get a chance to see if it fit's in the OEM APPS bellcrank assembly?

Mike