[tube]

Anyone ever notice that really anoying 1/2" or so of dead space in the gas pedal before the engine actually begins to rev?

My last car was a Subaru WRX with a cable throttle, I LOVED it, so responsive, so crisp.

Then I get my Mustang. The gas pedal is unresponsive, has load of dead space, and is a drivers nightmare.

Everyone always claims a tune helps their throttle response, so I purchased a Brenspeed C&L intake + SCT flasher combo. Unfortunately, 9 days after ordering it, no tracking # or item...

So today I'm at work thinking how I can mechanically remove that "dead space" in the gas pedal.

In my head, I picture the gas pedal module as being a carbon potentiometer, with a brush that is connected to the gas pedal, and moves, changing the resistance of the potentiometer, and thusly telling the ECU to open the throttle body.

Thinking some more, I decide to get my hands dirty.

I go in my footwell and look at my gas pedal. Simple enough, a black box with a plastic pedal coming out of it, three 10mm nuts, and 5 TORX screws holding a cover on the side, with an electrical connector and harness plugged into it.

I remove the three 10mm nuts, unclip the harness, and remove the entire pedal assembly.

Holding it my hand, I look at the cover, and take my T15 TORX driver and remove the cover. I pop the cover off, and VOILA to my assumption, a small circuit board, with a wedge shaped carbon film set of tracks, I think there are 6 to be exact.

I look at the inside of the gas pedal, and I see 6 little metal tabs, with about ten very fine metal wires, spot welded to the metal tabs, and bent up in a _/ shape to make contact with the carbon film on the circuit board.

I can clearly see a shiny track in the carbon on the circuit board where the metal brushes were rubbing against.

To my amazement, the track was starting about 2mm before the brush actually even TOUCHED the sensitive carbon part!!!

I take a pair of fine jewlers pliers, and bend each metal brush and tab just a few millimeters so that they will make perfect contact right on the edge of the carbon film.

I screw the cover back on, screw the gas pedal back onto the firewall and plug in the harness.

Start the engine, wait for the idle to drop. Perfect, idling around 700. I tap the gas pedal (with the tip of my TOE!)

and......





WOW the throttle is VERY responsive

THE DEADSPACE IS GONE! IT'S PERFECT!

It's amazing how such a small modification makes a HUGE difference in driveability and response.



Please digg my story!
Digg - Improving Drive By Wire Throttle Response Though Mechanical Means.

Step 1:

Remove Three 10mm nuts holding gas pedal to firewall:
http://i1.tinypic.com/6d0fygk.jpg

Step 2:

Slide back red lock tab on connector:
http://i19.tinypic.com/63uy79f.jpg

Step 3:

Use flat head screw driver to press tab down inside of connector, and pull connector away from gas pedal assembly:
http://i11.tinypic.com/66tqemx.jpg

Step 4:

Take pedal assembly over to your workbench. Remove five TORX T-15 screws on electrical cover.
http://i13.tinypic.com/6fuezxc.jpg


Step 5:

Remove electronic cover: Notice how the circuit board says REV 1.0? That means they haven't revised this gas pedal assembly since they first used it back in 2005!!! (My car is a 2008!)
http://i6.tinypic.com/67grd47.jpg

Notice the circuit board with the wedge shaped carbon tracks. Notice the shiny marks on the tracks. See how they start slightly before the end of the gold track? That is your deadspace! Any movement before the very edge of the gold track will not be registered by the ECU!!!

THE ONLY WAY to fix this is mechanical adjustment. NO amount of tuning can remove this deadspace, it's simply impossbile!

Step 6:

Look at the pedal assembly. Notice the metal tabs and fine wire brushes? These are what we want to modify.
http://i6.tinypic.com/4pyeum9.jpg

Very carefully, bend the brushes up so that they don't have such a steep angular bend in their tips. I have already done this in these photos, so it's not apparent how sharp the bend in the wires were prior to me modifying them. They are like this _/ and you want them to be straighter so that they move closer to the edge of the brass/carbon track.

http://i9.tinypic.com/4xonhjs.jpg


Using some fine pliers, carefully bend the tips of the wires. These are VERY fine wires, be very careful.

http://i1.tinypic.com/4ml6kc3.jpg

Now bend the entire metal tabs up very slightly to compensate for the change in angle at the tips of the wires.

http://i9.tinypic.com/4tanz8m.jpg

More pictures of the wires:

http://i15.tinypic.com/6bml9gm.jpg


http://i12.tinypic.com/548jz44.jpg

Another shot of the circuit board:
Notice that by bending the wires, we are moving them closer to the edge of the carbon/gold seam. This removes the dead space.

http://i6.tinypic.com/5ymfxo9.jpg

Step 7:

Put the cover back onto the pedal assembly. NOTE: There is a rubber gasket that goes in the slot. MAKE SURE not to lose it, or crush it, this could cause your vehicle to accelerate uncontrolably! Screw the 5 TORX screws back in VERY CAREFULLY do not distort the cover, or you may bend the wires and cause bad ju ju.

http://i9.tinypic.com/6h5dybk.jpg


http://i9.tinypic.com/4l4nyg6.jpg
Re-install the pedal, and enjoy your new dead space free throttle!

I am not responsible if you ruin your 50$ gas pedal assembly by breaking off the fine wires, or over bending them.

[stlwagon]

Wow... This is huge. What a great find.

[tube]

I hope this isn't a no-no, but here's my original thread on Mustang Forums, with a lot of discussion and clarification.

DIY THROTTLE RESPONSE MOD (MUST SEE!)

[sonny1213]

I have the lag bad about 20mph when coasting. Then try and ease the gas and there's the big dead spot.

[stlwagon]

I may pick up a spare pedal travel sensor and give this a try.

[travelers]

That's a item that takes a delicate touch.

[the72fins]

Wow that sounds great , i have the brenspeed 93 0ct. tune & the C&L and when i installed it the car woke right up, but after a month or so i swear the lag is back. I am not the best when it come to working on cars, im afraid if i try this i may screw it up bad. Does this really work??? any one else tried this yet?? I would like to here a lot more imput before i try this. If this works tube we may elect you president.......lol

stlwagon after you try your let us know how it works & how much $ the travel sensor was.

by the way tube great detail in your post A+++

[stlwagon]

I just ordered a new pedal travel sensor (P/N 4R3Z9F836BD) and a new throttle position sensor (P/N 6L2Z9B989A) from Bob Utter Genuine Ford Parts

[Brent05redfire]

holy crap! what a simple fix to the most annoying problem on stock GT's.

excellent case work, tube.

you can definitely see where the low rpm range is on the tracks. they are bolder where the gas pedal is used the most. and lighter where the gas pedal would be pressed to the floor.
tube, looks like you need more shiny marks on the other end of those tracks. maybe you wouldn't notice the lag so much. LOL

[pcfrisch]

Interesting, I would have thought they would have used a wire wound pot instead of carbon.
Cheap, cheap, cheap.

[IrishStang]

I think I might try this... After Stl tests the water for us.

[the72fins]

are we bending the very tips of the fine wires at the end?
or are we bending the whole assembly that is holding the fine wires? with the little wires bent down like that im not sure they would brush the circut board the right way. The may spread out over time and interfear with each other and touch. I'm not sure what that would do but those circuit's are seperated for a reason Am i thinkin right??

[don_w]

I'm guessing this isn't true for every car. I haven't had throttle lag in over two years... thanks first to Doug, and then to Adam. It's in the tune.

[pcfrisch]

Originally Posted by the72fins

are we bending the very tips of the fine wires at the end?
or are we bending the whole assembly that is holding the fine wires? with the little wires bent down like that im not sure they would brush the circut board the right way. The may spread out over time and interfear with each other and touch. I'm not sure what that would do but those circuit's are seperated for a reason Am i thinkin right??

It looks like he is bending both the wires and the tabs, It looks like there are a few wires on each tab for redundancy and to ensure good contact, so if they touch, it's not going to hurt anything. if they touched the traces next to them, that would be different. Mark is smart to get another unit to experiment on. The whole design looks pretty cheap to me. (I used to design pc boards).

[stlwagon]

Originally Posted by pcfrisch

It looks like he is bending both the wires and the tabs, It looks like there are a few wires on each tab for redundancy and to ensure good contact, so if they touch, it's not going to hurt anything. if they touched the traces next to them, that would be different. Mark is smart to get another unit to experiment on. The whole design looks pretty cheap to me. (I used to design pc boards).

It was $43 so well worth it in case I screw it up. I may open them both up and compare contacts before I decide which one to modify. It's going to be awhile before I get to this one.