I was on the freeway, doing about 60. I wanted to pass someone quick so I put the pedal to the floor. Right away I changed my mind and let up right away, but the rpm's flew up to about 4000 rpm's and stayed there for about 4 or 5 seconds before coming down to normal. Funny thing was that the truck didn't seem to change gears or react in any other way except to rev up the engine. No power was transfered to the driveline.

 

did it come out of overdrive? still too high i think.

 

Mine did that also, I was told it was due to the "fly by wire" throttle control. I have since reprogramed with the superchips unit...no more prob with that or the dreaded "throttle lag".

 

another wonderful advantage of the wonderful throttle by wire system that we have.

that's the computer trying to catch up with you getting on/off the gas so quick. this is exactly what the whole delay in acceleration is about. technology is great. welcome to the future!

 

Umm No. Thats the torque converter unlocked and not having any fluid pushed though it. All it did was downshift, tq converter unlock, then spin with the motor. When i found out this happened i could do it on my 99 ranger 4cyl i made it an art and did it all the time to make it seem i had a manual. But now i am 10sec faster 0-60 (new truck)

 

i don't know about the torque converter being the cause. My wifes Jeep doesn't do it, no other vehicle I have ever owned or driven has done it but my new Ford and apparently a lot of others with throttle-by-wire does it all the time.

I can duplicate this surge in rpm any time I wish in my truck. Once you get on the gas you have given an input to the computer to go (insert throttle lag here), whether you let off the gas or not it's still in sequence for acceleration because of the pre-programmed delay and continues forward because it has the voltage input stored from the original throttle input and once it gets past that point it no longer sees a voltage input from the peddle position sensor which stops the sequence and it resets itself. You are basically moving faster than the computer. That's why having the computer updated at the dealer or reprograming with a superchips/predator helps.

 

And to think.... the last time we could say we were "faster than a computer" was back in the old "punch card" days....
Give me my throttle cable anyday!

MK

 

I've said it before, and I'll say it again...why doesn't someone (company) come out with a real throttle cable conversion. I can't imagine it would be that hard...use the same TPS (throttle position sensor) but make the movement mechanical instead of an electric servo. That way, the fuel/air is still electronically controlled but the reaction of it is quicker (bypass the pedal sensor to computer to servo delay). Obviously I have no clue if this is actually possible, but it sounds good in my head!

 

Thanks guys.

I'm understanding things a little better. What I don't understand is why, with this rig, Ford has put throttle performance on the back burner when performance and power is what is supposed to be so great about this truck. I bet the new mustang doesn't have this problem.

 

It's not the "computer trying to catch up". For crying out loud, the TPS works at least 60x per second. There's simply no way it would take several seconds to catch up. Besides, and think about this: the engine revs increase but the truck doesn't accellerate. The torque converter is what's doing it. Now, the fact that there's no cable being pulled may be the reason why the TC is being fooled, but it's not because there is some huge lag in the computer.

 

I'am not talking about a 10 second delay in processing time. How long does it take you to put the peddle to the floor and release it? We're talking a split second here, but that is all that is needed to input a signal to the tps, which then gets relayed to the computer which then relays the appropriate signals to the all necessary components for acceleration to occur. Now add in the infamous delay and you get a delay in acceleration and it doesn't matter, 60 or 1000, how may times per second the tps reads the signal.

I don't think many here will disagree that there is a delay in acceleration, due to the lack of a throttle cable because the 5.4 has throttle by wire that is controlled by the computer. Now buying a tuner and reprograming the computer or having the computer updated at the dealer lessens or gets rid of this delay and is well documented on this board and others. That has nothing to do with the torque converter, wait, maybe what they are really doing is "reprogramming" the torque converter.

 

From now on we are using the NEW cover sheet on the TPS reports, did you get the memo? I'll see that you get a copy of the memo.

 

What are you talking about? I own the diablo u7151 and running the diablo tune and i can still get it to do it.

 

I think you got off track. To quote the original question:

"I put the pedal to the floor. Right away I changed my mind and let up right away, but the rpm's flew up to about 4000 rpm's and stayed there for about 4 or 5 seconds before coming down to normal. Funny thing was that the truck didn't seem to change gears or react in any other way except to rev up the engine. No power was transfered to the driveline."

We're not talking about the accelleration lag, we're talking about the engine revving for several seconds with no power transfer. You simply cannot blame that on drive-by-wire because power transfer happens in the transmission.

As for accelleration lag, it's possible with or without drive-by-wire. With drive-by-wire Ford could have chosen to put a slight delay or require a minimum throttle input in order to give the drivetrain the illusion of a smoother start. However, do some research and you'll find many complaints logged in auto reviews for transmission lag on many vehicles with conventional accelleration. So, just because there's a lag in the F-150 doesn't mean that only drive-by-wire systems have it. (It also doesn't mean that the throttle programming isn't the only cause of the lag).<!-- / message -->

 

Someone else try it, please. When you're on the freeway pump the gas once to the floor quickly and let up. What happens? I'd like to know if this is a common problem or if it's unique to my rig.