I do have power at my high idle solenoid but it doesn't advance the ip. I have searched and keep finding posts to check the connections to see if it has power...but mine does, it just doesn't advance the throttle. where do I get one?

 

Are you pushing down on the throttle to set it? The solenoid itself is not strong enough to move the throttle arm on the side of the IP, you have to step on the throttle and that lifts the pressure off the solenoid and allows it to set in the fast idle position, then when you release the throttle the truck will be idling higher. Also, are you sure you're checking the correct solenoid? The one you need is right by the upper radiator hose, with a little plunger sticking out and hitting the throttle arm. And since I mentioned the plunger, make sure yours is adjusted properly - with the engine off the plunger should be almost touching the throttle arm, if yours is far from it you can turn he plunger with a 1/4" wrench and unscrew it out some to where it almost touches...

 

I have tried to set it by pushing it down on the pedal.

I have owned the truck for six years and it always advanced the engine until it got the engine warmed up. Am I understanding that you are suggesting that it would get out of adjustment, proly through engine vibration?

 

IIRC the high idle solenoid is engaged by a sender on the engine block isn't it?

 

ive never seen or noted my high idle working. however on a warm truck i jumped my cold advance to test it and the high idle actuated.

 

THe sender for the high idle is on the passenger side directly behind the thermostat housing. you have to look from the top to see it b/c the filter is on one side and the rad. hose in front of it.

 

tomorrow i will see if I can get it to work by screwing out the plunger. Thanks

 

Nah, it won't get out of adjustment on its own, no amount of engine vibration can get that tight of a screw to turn - you'll see what I'm talking about when you go about adjusting it, it's almost as bad as the fuel screw in the IP. I was thinking more along the lines of the injection pump having been replaced at some point, and the high idle solenoid not being lined up properly on the new one...

Did you actually hear the high idle solenoid click (and move the plunger) tho? Cause just powering the cold-advance solenoid alone on a warm engine can get it to revv up higher, mine in particular behaved rather interesting when she revved up to 2500 on her own, then dropped down almost to a stall, then revved up to 2500 again, and so on

 

no i did not hear a solenoid click on a running diesel. (i spend most of my awake hours with earplugs in anyways) i did note it extend and move the arm. my cold advance doesnt seem to change the idle. it just seems to change the tone of the engine to that of electric rattlesnakes. id say my gain was only a few hundred rpm. cold advance is instant where high idle takes a sec or two.

id thought beforehand that my high idle just didnt work. maybe another interesting point is is that my engine starts exactly the same with the cold advance plugged in or not. most folk report hard or no starts without it?

 

You state you have 12v+ at the high idle solenoid ... That indicates the Thermal Switch is ok.

So, when the motor is cold (under 112F water temp)

1. Turn the key on
2. Unplug the high idle solenoid
3. Reach over and hold the throttle lever open a little
4. Plug the high idle solenoid back in
   Does it activate ???
   1. Yes, It works ...
   2. No, The solenoid is bad.

-Enjoy
fh : )_~

 

What Festus said, that's the easiest way to check it.

Also, if at cold idle your engine rattles like a PSD, then your cold advance is working like it should. Additionally, the fast idle is indeed only a few hundred rpms higher than normal idle, if you gain 300 rpms you can consider yourself lucky. The only reason I can get more out of mine is cause I changed the geometry of it some, so now the solenoid hits the throttle arm at a lower position thus turning it more for the same amount of throw at the plunger.

 

I've adjusted them up to about 1200 RPM on high idle without affecting normal idle without mods!

-Enjoy
fh : )_~

 

If you find that your solinoid is faulty, remove it from the I.P. Pull back the rubber boot to expose the widings for the electro-magnet. Check the ends of the windings and make sure they are still soldered to the connection. I repaired a couple that one end of the winding just became detached.

 

Yours seems to be a special case, in a good way. Either that, or my solenoid just don't have the throw it should... How far out does your plunger move when the solenoid is energized?

 

I guess that I don't know for sure that it was my high idle and not my cold avance. It used to speed up the engine, I don't have a working tach, I would guess 200 rpm. Whatever it did speed it up, it was perfect to get the engine warm faster without sounding like someone was standing on the throttle. The speed sounded just right.