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Installed the JMS PedalMAX

17K views 33 replies 17 participants last post by  Goose17  
#1 ·
After reading some positive reviews from Mustang owners on the JMS PedalMAX, I figured I'd give it a shot on my 2013 GT500. I've only had it on a few hours but wanted to pass along my findings thus far.

Install:
The device simply connects between the gas pedal position sensor and its wiring harness. There simply is no comfortable way to access the gas pedal plug area. That being said, it was a straight forward install only taking about 10 minutes.

Driving with the device installed:
There is a noticeable difference in the throttle response (more responsive). It does feel as though it accelerates quicker (if you can manage the tire spin...more on that later). I'd probably describe the overall "seat of the pants feeling" as it feels like the car has lost some weight.

Issues:
No issues with the device itself, so far. The only "problem" I've encountered thus far is less traction. It breaks loose faster/easier now than it did prior to install (with all the nannies on BTW).

I have put roughly 6000 miles on my current rear tires (Nitto 555r's). Therefore some fresh rubber may be in order soon. That alone may help put the tire spin back in check. If not then the device comes with an option to reduce the effect to 60% and I could give that a try.

Hope this blurb was somewhat useful.
 
#3 ·
2013-2014 Shelby's are notorious for 'stalling out'? Hmm...

What does the PedalMAX actually do to enhance the throttle response? Just wondering, as I have no idea how it works.
 
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#9 ·
#4 ·
I would like to eliminate the stalling, but not sure if I want to go aftermarket. Ford should step up and fix the problem.
 
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#5 ·
What is this "stalling" you guys are talking about?
 
owns 2020 Ford Mustang Shelby GT500 CFTP
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#8 ·
I just read it on the link Snoopy posted. I hadn't heard about it before either, which is why I thought it was a little strange, how it said they were notorious for stalling out...

That does sound quite bad Snoopy...quite weird, too. I'd look to get that fixed, rather than mask it with a mod. Have you had it looked at?
 
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#6 ·
In my case, it always happens at a stop light. I go to take off with light gas pedal pressure and I get no response and the car stalls, restart the car and the problem goes away. It has happened about 7 or 8 times since I bought the car. It's pretty embarrassing most of the time and could be deadly under the right circumstances.
 
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#16 ·
owns 2020 Ford Mustang Shelby GT500 CFTP
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#19 ·
Enjoyed talking to Monty from JMS at PRI, my brother just bought a nice 2011 FX2 Ecoboost F150 and will likely do their Boostmax OBDII plug in.
I like their fuel pump and ignition boosters for my E85 conversion that's in progress.
Just seems like JMS is not well known on the forums I visit.
The electronic drive by wire TBs can take getting used too, this seems like a good product for those hesitant to actually tune their cars for warranty issues.
-J
 
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#20 ·
Well, since this was dug up I might as well update my thoughts on the PedalMAX.

Right after installing the pedal max "thing" there's an immediate & noticeable difference in the way the throttle feels. However, within a couple of restarts, it seems to go back to normal. It's as though the computer defeats it. At least that's how it feels to me.

I ended up removing it because it didn't maintain that crisp throttle. It now sits in a box on a shelf and I just reset the ECU once a month to get the crisp throttle response back (which also goes away after a couple of restarts). Anyone else have to do that because your car becomes sluggish feeling over time or is it just me?
 
#21 ·
I have had mine stall out a few times on me. Seems when I go to work at 0445 I try to be nice to the neighbors and not just take off. When I do that mine always stalls and then the restart wakes them up. If I take off with a little more (I guess) push on the pedal it has never stalled on me. I just figured it did not like a slow take off and wanted to be rev'd a bit higher to wake up the neighbors. That is about the only time I have ever had it stall on me.
 
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#22 ·
Mine does this stock and has done it since new. Very annoying.
 
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#24 ·
Is this a 13/14 issue? I haven't heard any issues on stock previous years.
 
owns 2020 Ford Mustang Shelby GT500 CFTP
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#26 ·
I do use more throttle now. It took awhile to figure out it didn't like soft take offs and my neighbors said just go and don't worry about it.
 
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#27 ·
Unfortunately, the stalling/rough idle is a real issue for 13/14's. It happened to me once. I thought that I had broke something. I called BJ at VMP because I thought it was the tune and he explained that it was a known (however rare) issue. After a few moments, I fired it back up with no issues. Since then, I have had zero issues however, I know its always possible. My Ford dealer acknowledged it too and said there is no fix for it.
 
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#28 · (Edited)
The occasional stalls that have occurred on my car were driver error.With the music on,the hydraulic no feel clutch and the tbw I get a few. Not a biggy and no music helps, so you at least hear the motor on gentle take-offs.
 
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#29 ·
The occasional stalls that have occurred on my car were driver error.With the music on,the hydraulic no feel clutch and the tbw I get few. Not a biggy and no music helps, so you at least hear the motor on gentle take-offs.
The tall first gear in the 13/14's does not help with this.
 
owns 2020 Ford Mustang Shelby GT500 CFTP
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#32 ·
I've had a " dead pedal " more than 6-7 times with my '13. I was told to turn off the ignition and restart which fixes it. It usually happens when standing still at a light ....motor sits at idle with no pedal response. I thought it was the TB .....or the connections .
In any event it has not happened in a while....it never stalled but remains a mystery.
 
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#34 ·
This thread is over 5 years old and now closed due to age. Please start a new thread with your question. Feel free to link to old threads, but please don’t bring them back from the dead.
 
owns 2020 Ford Mustang Shelby GT500 CFTP
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