My 07.5 has an issue driving me crazy. Bone stock truck 121k miles.

When driving along if you get on the truck at all, when you push in the clutch, the rpms rise or hang, then fall to idle or to wherever they should be to hit the next gear up. If you let off the gas totally before pushing in the clutch, then it is very minimal if at all. But who drives that way....

I had to get on it as I noticed someone coming up behind me pretty quickly, and went to grab the next gear without using this modified shift technique, and the rpms shot up about 4-500rpm before the clutch drug them down.

Anybody have any experience with this?

I have gotten one PM saying that the deletes fixed the problem for him.

Anybody else?

 

I have had my 07.5 since new it now has 36,000 miles on it. I have had that same problem Ii have not been able to get any answers on how to fix it. so i pretty much have gotten use to it. let me know if you find anything out.

 

Hi DC89SSP, I found your PM and just now answered. I think you are talking about the same thing mine does. Like BlackRaptor I just learned to live with it. (didn't like it though) I hope these mods I did fix that. I'll let you know if it does.

 

Nope, I just drove it and still has the hang time in the throttle response. I watched the tac and it actually, depending on speed and rpm, the rpm can rise some.

 

Thanks Rob.

Got Soot on here and I have been talking by PM about it. He says his either went away or got much better after the deletes.

So by all means keep US ALL updated.

Many people have said their '03 & up common rails have done the same thing. It makes me think it may not be emissions related. I want to be wrong.....

I may sell mine if I can't fix this. It pisses me off that much.

 

Mine may be some better than it was before the deletes but still there. After three years I really didn't notice it that much but it really bugged me when it was new.
My 2001 was sooo much better in throttle response. I think this is a delay built in to the electronic throttle control or computer or something. One thing I really loved about my 01 was; if you took off in 2nd (or even 3rd) on level ground and not give it any throttle it seemed the computer percived it was being lugged and throttle up on it's own. If you were used to it that made it VERY driveable.
Rob

 

I talked to one other person the another forum and he said that his truck ran better and better over time after the deletes. So although it was much better immediately, it got even better over time.

He owned a 6.7 for about 80k miles.

 

He is racing and I don't hear the rpms flaring. It may be that his just letting the clutch drag the rpms back down.

http://www.youtube.com/watch?v=80DdXpBiH0c

 

Rob how is your truck doing now that you have more miles on it????

I have spent more time behind the wheel of my 3500 and am getting the shifting down where I like it better.

I saw my buddy drive off in my F350 to put a stereo in it. **** it sounded good. Love that commpression ignition.

Our 6.7s are too **** quiet. Need more rattle.

 

Here's the real deal. Look at it like this, throttle = RPM and Load % = fuel. If you ask for 2000 RPM and are making 1000, the load % goes up and fuel is increased. This is the how the zero throttle launch works. The throttle calls for 700 RPM, or idle, and you go to take off, the RPMs drop and the ECM calls for fuel to make the requested 700. Pretty neat. Well all that computing takes time and the fuel pressure has to bleed off, which gives you the throttle lag.

The fix...
You have to have the load % go to zero before shifting. I know, you let off the throttle so the requested RPM is 700. Well, not exactly. Most of us don't let off the throttle then push in the clutch, it's more coordinated. Both feet are moving, right?

The fix.... in practice...

You have to shift at the point that the load goes to zero. How to find it? Apply very light pressure out of gear and let off the throttle, when it slips out of gear, push in the clutch and shift away. Listen to the turbo and feel how the truck stops pulling. You'll learn how to time it. I describe it as rolling off the throttle instead of lifting your foot, before you shift.

 

PS: It has little to do with emissions. It's the computer. Changing the "plumbing" on the engine just allows values to stabilize faster and eliminates sensors that have to be in harmony for fuel mapping.

 

I have got the shifting down pretty good now. It's fairly enjoyable. I'm not drag racing the truck.

I took the truck up in the mountains for a retreat this past weekend and I loved it in the hills. The steering in my truck is so precise I could put the truck anywhere I wanted in the twisties. It was amazing what an 8000lb truck could do. Obviously i don't have any death wobble.

My Ford would have been tons worse. the steering in an F series HD plain sucks.

Also going down the mountain i put it in 5th and let the exhaust brake do the work. Good fun.

Really enjoyed the truck.

Now I just need new tries and my highway vibration will be gone.