silverbullet02

Truck has done this since I've owned it, about 15k miles, but it'll idle a good 50-100 rpm lower than on a flat surface idling uphill and conversely it'll idle a good 50-75 rpm higher than on a flat surface when pointing downhill...same effect when you hit the brakes hard it'll idle up too till you let off and it goes back to normal...just doesn't seem to make sense, other than trying to pull from the tank is harder one way than the other, but it runs great otherwise, pulls hard, runs smooth, etc...just wondering if anybody else experienced this. Thanks,

Brian

wannadiesel

How steep an incline are we talking? The governor lays on its side and has very little spring tension on it at idle, I could see it being affected by a steep incline. And the way it lays in there, it would be faster downhill and slower uphill.

Mine does the "hard braking" bit too. I'll have to pay closer attention to how it idles on hills. There's steep uphill grade close to work that I usually have to sit on for a light cycle on the way home. I've noticed it idles slow there but I always chalked it up to the engine being cold still.

G1625S

I get the hard brake idle increase too. Weird.
g

frostie

That is interesting, What if the fuel transfer pump is week and causes The pump to loose pressure aiming up hill and gain pressure nose down. Just a thought

92DIESEL

I've noticed the same with the brakes. i don't have a tach but i can hear a difference.

wannadiesel

18 psi at idle isn't weak.