Engine/Transmission (1994 - 1998) idle adjustment

[Piersol]

I have a 1996 with the auto transmission and when I started it this morning it idled at about 1150 rpm and wouldnot come down. After a 25 mile ride to work it still idled high. Started it up after work and it still idled high, but maybe only 950 rpm. Tonight I tried to adjust the idle lower but with the screw all the way in it is not even touching the cam anymore and it still idles high. About 880, which I know is within tolerance but still seems high. Any thoughts.

 

[gitchesum]

You might try the throttle cable or the throttle linkage. It might be binding up causing that problem

 

[Piersol]

The throttle cable was replaced with the updated model about 50,000 miles ago. It seems free and non binding.

 

[Joe G.]

Two springs to check. There is one on the linkage between the lever near the rear of the pump and a hook it fits over. There are actually two springs wound together. Sometimes the hook rusts thru and only one of the double springs is doing all the work. The other spring to check is the one from the transmission kick down lever to the bell housing. If it's broken or missing it would cause the symptoms you have.

 

[JJW_ND]

Rusty or dirtly ball sockets at either end of the throttle rod will cause the idle to change.



jjw

ND

 

[pwknapp]

Mine was binding real bad and idling erratically. Found out the pivot assembly at the front of the block was slap worn out. The stealer wanted almost 200 for a new assembly so I had a new bushing made out of brass. Welded up the pivot stud where it had almost worn through and then machined it down to fit the new brass bushing. Hope this will last longer than the original

did, only 400k.

 

[Joe G.]

Originally posted by Piersol

The throttle cable was replaced with the updated model about 50,000 miles ago. It seems free and non binding.

From what Piersol says here I doubt that binding or rust is the problem. Of course, it may be only binding at the limit of travel and free otherwise. If the foot pressure necessary to press the pedal is very light it's a spring problem where the springs are just not returning the linkage to the stop. If normal then I would check for some sort of obstruction like a hose in the way. Lots of stuff hanging around in that area. Might also want to check to see if carpet or floor mat is hindering the pedal.

 

[Piersol]

I'm leaning toward an obstruction myself. If anything, I have a little more pressure at the pedal than usual although I'm wondering if I'm just thinking it so. What is that rod down low under the pump? It looks like it has two lock nuts and ball sockets at each end. I did lube those up and it seems a little better. If it was a spring problem I would think I could manually push it back to normal idle, which I can't. With the engine off it is hard to move the throttle. With the engine on it moves easier. Is that normal? In the cab everything seems free.

 

[Joe G.]

It's normal for the throttle to be stiffer when the engine is off. When the governor is turning the throttle is easier to move.



The rod under the pump is your linkage rod. One end goes to the lever on the bottom of the front linkage with the coil spring. The other end goes to the pump lever. Part of it is a turn buckler type of thing so the rod length can be adjusted. The lock nuts are to secure the length adjustment.



I forgot about a little thing that got me once. It might be the problem with yours. Worth checking anyway. The lever on the back of the pump that touches the idle stop is NOT the same lever that the linkage connects to. You would think so from looking at them, but they are separate. The linkage lever fastens to the pump lever with two little screws. If one has fallen out there is your problem. On mine they were both about to fall out so the fit was really sloppy. Tighten them with a 8mm wrench.

 

[Piersol]

Thanks all who have replied. It appears that jjw ND had the answer. I lubed everthing up with some synthetic spray lubricant and that SEEMS to have fixed the problem. I will reserve judgment until we get another cold day like when it started but it SEEMS to be fixed. Thanks to all.

 

[JJW_ND]

Just so you don't have the problem quickly return... . Make sure you remove the rod and clean out the sockets and wipe off the balls. Put some heavier grease in the sockets and reinstall.



Mine had tiny wire clips that held the sockets on. Once I had them figured out they come off and one pretty easy.



I just sprayed some WD40 in the sockets while attached. A very temporary fix!



jjw

ND

 

[Piersol]

yea JJW. I'll do that.