Sensitive/Jerky Throttle (bad TPS?)

[RobG]

Today, Frank Dziurda and I did some comparing between his '99 6-speed and my '01 6-speed. I was curious to see if his throttle was as sensitive as mine.



My throttle responds to the slightest twitch of the pedal, which causes the truck to buck, which makes my foot move around on the pedal more, causing the truck to buck more. It's a catch 22.



I drove Frank's truck and his is very smooth. He drove mine and said that while he didn't quite see the jerkiness I described, he did say that my throttle appeared to have a dead spot on tip-in.



Another thing we noticed is that on his '99, when you set the cruise control, the pedal stays depressed. On mine, it doesn't. Both of us have cables going from the pedal to the VP44, but his apparently keeps the cable tensioned, and mine doesn't. I'm wondering why this is, and if it can be changed (or if it's normal). My pedal fully relaxes when the cruise is engaged.



So... could the sensitivity problem be the result of a bad throttle position sensor?



Rob

 

[JHansen]

Hey Rob-your 2001's cruise control is servoless-the actual workings are done right in the ECM. The older ones still used a vacuum servo under the left battery to pull on the throttle pedal-hence the difference in pedal feel.



I dunno what to tell you about the sensitive pedal. Mine jumps pretty good with just the 275's and EZ over rough ground-although the Practical Solutions high idler I've got will dampen it if just switched on. I'm sure Gordon never designed it for this-but it does the job!



Jason

 

[PRout]

Originally posted by RobG





My throttle responds to the slightest twitch of the pedal, which causes the truck to buck, which makes my foot move around on the pedal more, causing the truck to buck more. It's a catch 22.



Rob

Could this be a normal characteristic of having the big nozzle injectors?



Seems that a small increase in throttle would allow big injectors to flow more fuel at slight throttle settings as compared to small injectors. You'd lose the "fine" throttle response.





Have been considering moving up to DD3's, but dont want to get a more jerky throttle response.



If this is the case, could you use a fueling box to "defuel" for normal driving to keep it smooth?