Electronic Throttle Response Dampening

[gahanna-6.4]

The 6.4 throttle response is not sluggish due to turbo lag. The sluggish feel is due to the 'fly-by-wire' throttle setup. The computer is dampening fast sharp throttle changes at certain lower speeds, especially from a dead stop. If the truck is completely stopped and you floorboard it (without power-braking it) the computer will dampen the throttle throw. Same if you're just rolling along under 25mph or so. I've found many speed ranges where I cannot even 'blip' the throttle... no response at all on fast blips. Im assuming Ford has done this to decrease jerkiness, prevent drivetrain damage or prevent occupants from bashing their heads on the headrests. I've also found that the computer wont return the throttle right away either in some instances. I was in a drive-thru and blipped the throttle while pulling up in line and it held itself 1000 rpm or so for about a second - definitely felt kind of weird. I was also able to get a CEL while playing around in a parking lot blipping the throttle. The truck began idling around 900 in or out of gear and the response was horrible as if it was in limp mode. To clear the CEL all i had to do was shut it off and restart it. Now that I have the SCT I'd like to try to get that CEL again so I can post the number.

Im sure the Ford engineers put a lot of time and effort into making our driving experience much nicer by dampening the throttle response for us... but I dislike it. If the electronic throttle position scale goes from 0 to 100 and I call for 100, i want it opening the throttle body instantly to 100, not ramping it up to 100 over a 2000ms time step.

I'm hoping that in the next release of tunes from either SCT or Spartan that they have the ability to get into the portion of code that controls this dampening on the throttle response and tighten it up a bit so that the throttle response is a bit more like having a physical cable connected to the throttle body.

[Barchetta]

You might be on to something with that. I have noticed that my does exactly what you described as far as not going WOT from a stop. If I power brake, then I have a rocket ship, but not otherwise. Building boost helps a little too!

[Pahrump]

My Spartan tunes seem to have really helped throttle response...not 100%.....but some.

I can still be rolling, and just blip the throttle...get a puff of smoke, but no change in RPM's, I would say this is due to the aggressive fueling of the tunes, but the lack of throttle response that FORD put in.

[nordberg]

that would explain why a six ohh has so much more bottom end

[Pahrump]

Originally Posted by nordberg

that would explain why a six ohh has so much more bottom end

Yeah...cable actuated butterfly

[gahanna-6.4]

I found another forum for the F450 V-10s and they are complaining of the exact thing we are here. One of them posted a procedure to re-calibrate the pedal to the TPS and servo - which is normally used if either the TPS on the pedal or the servo motor on the TBI is replaced:

Ford Electronic throttle pedal recalibration

The procedure:

- Turn your key to the ON position (not just ACC), wait for the various dash warning lights to go out - but do NOT start the engine.

- Press your throttle all the way down in one smooth motion - just do it at a normal speed (take about 2-3 seconds to hit bottom).

- Let it up, as soon as you hit the bottom.

- Turn off your ignition and wait 3-4 seconds.

- Start the engine up normally and drive.

May have to repeat 3 times for the Computer Training to complete.
This procedure trains the throttle position sensor to the throttle body servo motor.

Unfortunately, the ECM quickly relearns and begins dampening your throttle response again. I just tried it in mine and it worked like a charm for about 5 minutes! You would not believe how crisp the throttle was, it felt like a completely different truck TONS of bottom end, roasted the tires like I power braked it - almost as if there was a real cable between my mashpad and the throttle body. Too bad it only lasted a few minutes

We definitely need to get SCT and Spartan involved to find out if they can change any of the parameters in the TBI dampening.

[Barchetta]

Originally Posted by gahanna-6.4

I found another forum for the F450 V-10s and they are complaining of the exact thing we are here. One of them posted a procedure to re-calibrate the pedal to the TPS and servo - which is normally used if either the TPS on the pedal or the servo motor on the TBI is replaced:



Unfortunately, the ECM quickly relearns and begins dampening your throttle response again. I just tried it in mine and it worked like a charm for about 5 minutes! You would not believe how crisp the throttle was, it felt like a completely different truck TONS of bottom end, roasted the tires like I power braked it - almost as if there was a real cable between my mashpad and the throttle body. Too bad it only lasted a few minutes

We definitely need to get SCT and Spartan involved to find out if they can change any of the parameters in the TBI dampening.

That sounds awesome! Too bad it won't stick.

[George C]

That would explain everything.
Nice post.

Maybe this qualifies too:

I used to drive truck over the road in my 20's when I was young and unmarried.
I always drove a 3406B Cat, but I got a new KW Aerodyne conventional with a 400 Cummins in it. Nice truck, but I hated the engine because it was, well, not a CAT, and the throttle response was so dull.
Long story shorter, there was a valve called the aneroid (sp) valve on the pump that was slowing up the response. The reason for the valve was to lay the fuel onto the pistons easier, to reduce the instant stress on the pistons, rods, driveline etc..
When we disconnected the valve, the thing reacted like a champ.

It is probable that Ford is doing the same thing electronically to reduce stress caused by people like us.. Allowing the fuel to enter the engine smoothly reduces fatigue everywhere.

Now, someone fix it!

Nice work Gahanna!

[gahanna-6.4]

Originally Posted by George C

That would explain everything.
Nice post.

Maybe this qualifies too:

I used to drive truck over the road in my 20's when I was young and unmarried.
I always drove a 3406B Cat, but I got a new KW Aerodyne conventional with a 400 Cummins in it. Nice truck, but I hated the engine because it was, well, not a CAT, and the throttle response was so dull.
Long story shorter, there was a valve called the aneroid (sp) valve on the pump that was slowing up the response. The reason for the valve was to lay the fuel onto the pistons easier, to reduce the instant stress on the pistons, rods, driveline etc..
When we disconnected the valve, the thing reacted like a champ.

It is probable that Ford is doing the same thing electronically to reduce stress caused by people like us.. Allowing the fuel to enter the engine smoothly reduces fatigue everywhere.

Now, someone fix it!

Nice work Gahanna!

Hrm.. I suppose thats possible. I just talked to a good friend who is a ford mechanic (not a diesel tech) and he said they are definitely damped hard in the trucks. The reason for this is that if you are towing and hit a series of bumps (you know the kind of bumps he's referring to, the kind of bumps that make your voice waver if you're talking) and your foot bounces around on the throttle you could possibly bounce your head off of the cab or damage the drivetrain if the throttle was uber responsive.

[George C]

To me, throttle response is EVERYTHING.
It makes the overall drivability so much better.
If they can get that figured out, I'm happy, happy, happy!
The 158 has everything I need in the mid to upper power department. I don't need any more than that (OK, blatant lie) , just give me some instant torque after I make a turn.