Throttle cutting back
 

Hi,

I have a '97 Cummins w/ auto trans/ 125k on the odo

It shifts fine - but going up a hill my throttle cuts back on occasion and is unresponsive to more pedal- you can put it to the floor with no effect. Seems to be getting progressively worse.

No check engine light on. ran a scan and no fault codes come up. Only clue I have found is TPS voltage with key on/engine off is 0.70 and minimum should be 0.76

does this sound like a faulty TPS ? Anybody have any clues?

thanks!

it cuts out around 2200 - 2400 rpm? do you have stock gov springs?

yes - I would say that is about where it cuts out.

It does maintain higher rpms when I first get rolling. It just seems to be after a shift and usually going up hill. Otherwise it has plenty of power.

Everything is stock and pretty much as I got it off the shelf. Original owner here and it has needed nothing other than filters and a couple of fuel lines replaced a year or 2 ago.
thanks for the response-

Keith

you should check the TPS to make sure you have the right voltage. A set of gov springs will give you some extra power above the 2400 rpm wall of the stock springs

you can knock the metal tabs out and drill those mounting holes larger, then rotate the tps counter clockwise for a increase in voltage. sounds like your gov. springs to me as 94 12valve said.

Maybe its my poor reasoning, but if the truck is able to hold the higher rpm under certain conditions , wouldn't that indicate something other than the governor springs? I was thinking more along the electronic controls direction.

admittedly this is pretty much out of my field and am open and thankful for all ideas.

The problem with the stock governor springs is that they restrict fuel after 2200. So, the gov springs do two things. Defuel after 2200, and keep you from going over 2900.

I doubt anyone changes the springs so they can get more RPM's. These engines don't really benefit any by going over 3000. They mainly do it to remove the defueling effect of after the 2200 mark.

Which in your case... would allow you to accelerate when going uphill well into the 3000 RPM, mark; instead of only 2200.

However, seems that changing the spring gives you a sensitive pedal more often than not (more so for with the 4K kit). Which is one of the reason why I haven't done it to my truck (even though I already bought the kit some time ago). Then I do live in a area that has no hills. Plus, my Dad talks me out of it every time, I bring it up... And I'm too C.S. to do it by myself.

Oh, and the only difference between the 4K kit and the 3K kit is that the 4K kit gives you the inner springs to change out. So, if you don't install the inner springs on a 4K kit.... it becomes a 3K kit. At least that's what the instructions tell you on the Pacbrake brand.

I disagree with the point made in bold

Defueling- yeah that sounds like what is happening - like the pedal is coming up off the floor.

Sounds like I have 2 directions to look in which is good. thanks for the input!

When your Gov spring is defueling it shouldnt have any effect on your throttle pedal, if your pedal is coming up when you accelerate up hill I'd check things like engine, trans, and cab mounts :c: