Need APPS info?

RattlinFord · Feb 3, 2015

Anyone who's read my other post knows that I'm trying to weed out a shifting issue with my early 99 F250. It's shifting hard into 4th under load and the TCC is working in reverse, seemingly. When you give it about 1/2-3/4 throttle, the TCC locks in...when you back out of the throttle to go to "cruising speed", the TCC unlocks. So that catches y'all up.

Talking to people, and checking things, leads me to suspect the APPS. I thought I had a smoking gun...because I hooked a scanner to my truck and at full throttle it only shows 73% throttle and 3.6 volts. Thought for SURE that was my issue.

Enter today...my buddy has a late 99 F250 and works at a Ford dealer as a diesel tech. We hooked the scanner up and there was no dead spots or spikes in the APPS. Then we hooked to his truck which runs/drives great. His truck only read 76% throttle and 3.8v!

So, can anyone give me the real scoop? I've searched until I feel I can't anymore. Do any of these go to 100%? Or are they tuning-limited? He has a TS 6-position chip and his still doesn't show but 76%. I saw an article on adjusting the APPS (making it adjustable)...anyone ever done this?

Or, is this all me just not being use to an early 99 tuning and the transmission just is gonna shift crappy until I'm tuned? It doesn't slip. It shifts smooth as butter and quick when not under load. But under load it's kinda crappy. The TCC issue is there non-stop. Might wire in a manual override for that. Anyone have any advice/info?

lincolnlocker · Feb 3, 2015

pm mark kovalsky and ask him to check this thread out.

live life full throttle

RattlinFord · Feb 3, 2015

He was the one I talked to. I can have him look but I'm not sure he's gonna have a lot more info...

Big Bore · Feb 3, 2015

Switching to a later PMT1 computer and tunes is probably the only way out of that one. E99 computers had a pretty lame trans control/shift map from what I remember tuners telling me.

RattlinFord · Feb 4, 2015

Yea that's what I thought. Thanks bud!!

Mark Kovalsky · Feb 4, 2015

The early 99's didn't have the best programming. Later was better.

I'll bet the PCM is seeing the brake lights on. If the brake lights are on (or it THINKS the brake lights are on) the converter will only lock at higher throttles.

I assume by APPS you mean pedal position. I've never heard it called APPS before. If you are, then 73-76% is completely normal. I've never seen one go as high as 80%.

RattlinFord · Feb 4, 2015

yes Mark, that's what i meant. and cool, i just wondered if it was normal. and, it's funny you say that about the brake lights. it had a code for a shorted brake light switch, but i replaced the switch. i THINK the code is gone but i haven't got 'er back on a scanner yet. the brake lights were working fine and are now. how would i go about making the PCM realize they aren't on (what's a common fail that causes this, basically?) I'm thinking about just wiring in a manual override so i can lock in the TCC when i feel it's necessary. Guzzle's page seems to have a pretty good setup.

lincolnlocker · Feb 5, 2015

RattlinFord said:
yes Mark, that's what i meant. and cool, i just wondered if it was normal. and, it's funny you say that about the brake lights. it had a code for a shorted brake light switch, but i replaced the switch. i THINK the code is gone but i haven't got 'er back on a scanner yet. the brake lights were working fine and are now. how would i go about making the PCM realize they aren't on (what's a common fail that causes this, basically?) I'm thinking about just wiring in a manual override so i can lock in the TCC when i feel it's necessary. Guzzle's page seems to have a pretty good setup.

just so you're aware of marks credentials, he was in on every aspect of the 4r100 trans as in he designed built and tested it..... he knows every millimeter of that trans like it was the back of his hand...

live life full throttle

79jasper · Feb 5, 2015

Mark Kovalsky said:
I assume by APPS you mean pedal position. I've never heard it called APPS before. If you are, then 73-76% is completely normal. I've never seen one go as high as 80%.

I guess it's unrelated to his problem, but I wander if "blue printing" the pedal would allow a better pedal voltage reading? I.e. higher.
Most drive by wire gassers call it a apps, I just say tps.

Sent from my SM-T537R4 using Tapatalk

RattlinFord · Feb 5, 2015

lincolnlocker said:
just so you're aware of marks credentials, he was in on every aspect of the 4r100 trans as in he designed built and tested it..... he knows every millimeter of that trans like it was the back of his hand...

live life full throttle

Yea I knew he was a former engineer...I'd just talked to him before. But, maybe he or someone can chime in on how I'd determine the ecm is seeing the brake lights (a scanner, I'd assume), and how does this problem commonly get fixed? Is it normally a wiring short or some switch/relay stuck?

RattlinFord · Feb 5, 2015

79jasper said:
I guess it's unrelated to his problem, but I wander if "blue printing" the pedal would allow a better pedal voltage reading? I.e. higher.
Most drive by wire gassers call it a apps, I just say tps.

Sent from my SM-T537R4 using Tapatalk

I read about that and wondered the same thing. I wondered if I would get better performance by blue printing it...

Mark Kovalsky · Feb 5, 2015

lincolnlocker said:
just so you're aware of marks credentials, he was in on every aspect of the 4r100 trans as in he designed built and tested it..... he knows every millimeter of that trans like it was the back of his hand...

live life full throttle

Thanks, but that's not really what I did. I didn't design the 4R100, in fact, I was never assigned to that transmission department as my assignment at Ford.

I worked directly on the AXODE, the 5R55N/S, the TorqShift 5 speed, and then on to transmission cooling. During part of that time I was a volunteer calibrator (i.e., I developed the trans tunes) for Ford's off road racing program. We ran an E4OD, then a 4R100, and then a TorqShift.

RattlinFord said:
Yea I knew he was a former engineer...I'd just talked to him before. But, maybe he or someone can chime in on how I'd determine the ecm is seeing the brake lights (a scanner, I'd assume), and how does this problem commonly get fixed? Is it normally a wiring short or some switch/relay stuck?

There is a parameter in the software that is 0 when the brakes are not on and 1 when they are on. It was called BOO, which is an acronym of Brake On/Off.

RattlinFord said:
I read about that and wondered the same thing. I wondered if I would get better performance by blue printing it...

No, it won't. Everything in the software is designed to recognize 70% as WOT. Any number larger than 70% is treated as the maximum.

lincolnlocker · Feb 5, 2015

Mark Kovalsky said:
Thanks, but that's not really what I did. I didn't design the 4R100, in fact, I was never assigned to that transmission department as my assignment at Ford.

I worked directly on the AXODE, the 5R55N/S, the TorqShift 5 speed, and then on to transmission cooling. During part of that time I was a volunteer calibrator (i.e., I developed the trans tunes) for Ford's off road racing program. We ran an E4OD, then a 4R100, and then a TorqShift.

There is a parameter in the software that is 0 when the brakes are not on and 1 when they are on. It was called BOO, which is an acronym of Brake On/Off.

No, it won't. Everything in the software is designed to recognize 70% as WOT. Any number larger than 70% is treated as the maximum.

lol.. that too!!

live life full throttle

RattlinFord · Feb 5, 2015

Mark Kovalsky said:
There is a parameter in the software that is 0 when the brakes are not on and 1 when they are on. It was called BOO, which is an acronym of Brake On/Off

Yea, I've heard of "BOO" before. What would commonly cause this condition with a new brake light switch? Any common causes? I'm pretty sure my electric trailer brake controller is fried (constant 12+ to brake wire), could that cause it? I might try unplugging it from the harness and see.

Mark Kovalsky · Feb 6, 2015

The bad brake controller might cause this.

RattlinFord · Feb 6, 2015

I unplugged it, same behavior. But it was good to rule it out. Gonna hook a scanner to it most likely today and see what's going on with it.

RattlinFord · Feb 12, 2015

Hey Mark, finally got to check it and you were right...the BOO is showing on all the time. Any ideas where to check for issues? The brake light switch is brand new.

79jasper · Feb 12, 2015

Check the harness right near the plug.

Sent from my SM-T537R4 using Tapatalk

RattlinFord · Feb 12, 2015

Ok I'll do it. Thanks bud!

Mark Kovalsky · Feb 16, 2015

RattlinFord said:
Hey Mark, finally got to check it and you were right...the BOO is showing on all the time. Any ideas where to check for issues? The brake light switch is brand new.

Unplug the switch and see if it still shows always on. That would eliminate the switch as the problem.

I've seen this happen with a bad brake light bulb. A filament broke inside the bulb and shorted. Somehow this made BOO always read on.