while i was under the hood, after i changed the glow plugs, i did some test light action, and found i am not getting power to the high idle solenoid.
i can not find reference to it in the service manual. where does the solenoid get power from???

 

I think it comes through the tempurature sending unit that is tucked just to the passenger side of the pump and in front its tough to see hidden way down there. If you take your test light you will see where the power stops it should on one side of the sending unit and not on the other

 

Look down by the thermostat housing. When messing with the glow plug harness it is easy to dislodge the connector on the temp switch. Two prong plug in type connector.
If you are not getting fast idle current you are not getting timing advance current either. Same wire feeds both solenoids.

I use a set of long bent nose pliers to put it on, no way your hand will go down in there.

 

is there a way to test the the 2 prong temp switch installed? how common is it for them to go bad. replaced glowplugs, controller and relay last month, now i lost the high idle and doesn't run as smooth as it did.

 

thanks dave, i will check it out later after i get it shoveled off. it was not my doing, it has not worked for at least 10 years since i had the injector pump put on.. just a little lazy. i am a firm believer of if it ain't broke, don't fix it. but i figured since i was already up there, i would get the test light and do some troubleshooting. you need a step ladder to do simple things like checking the oil, so the less i get up there under the hood, the better i am. i am gettin to old to be climbin that high. ( or at least the kids say so)

 

Roybee.....using a meter check for continuity between the electrical tangs of the coolant temp switch when the engine is cold. When engine is warm there should be no continuity. Check the power lead for 12V with the key turned on, if you have power to one side, jumper it, the fast idle and timing advance should work.

 

Tom, Since the wire goes straight from the coolant temp switch to the IP it would have been even easier to dislodge the connector while replacing the IP.

Know what you mean about the kids, they think they know everything. I have one at my house too.

 

if the sensor is bad, can i just bypass it with a relay and low power trigger from a toggle switch in the cab to get a on demand high idle, or will it being tied into the timing advance circuit cause troubles??

 

well Dave you were correct again. the plug was off the sender.
i will have to wait till tomorrow morning to see if it is gonna work.
is there anything you do not know???

 

There are a couple of things, but I even have opinions on them correct or not.

Actually,

All I can say is been there did that.
Remember, I have done 5 engine swaps in the last two years in my truck.
The two mechanics that help me and myself can actually swap an engine in 8 hours now from the time it comes in the door till it drives out the door.

I am in the over 50 crowd so I have seen a lot of stuff over the years.
Lots of it was a good idea, lots of it had no possible way it could work.
I just tried to pay attention and not make the same mistake twice reguardless if it was my mistake or some engineers.
All the good things I have seen I try to figure out how to adapt to my application.

Makes for an interesting life and a good running truck.

I grew up on a farm and my grandfather owned the local Ford garage.
One of my first attempts at modifying something was at a rather early age.
We had an old backhoe on the farm that always had a dead battery.
The mechanics kept changing the generator, regulator and batteries.
It would always work for a month or two before it was dead again.
One day it was dead when I needed it for something so I took it all apart, made a couple of brackets and installed an alternator on it. Then I rewired it so the alternator worked.
My dad saw it and was ready to kick my butt, but he got on the backhoe to see how bad I had messed it up and it started right up. So he let it ride for a couple of days. Still it started right up. A couple of years later when we sold it, it still started right up. I was probably 10 or 11 then, I have been at it every since.

 

pretty much the same thing here, except no ford dealers in the family. farm raised, and at 13 i became the mechanic cause i liked doing it. actually, it was better than being out in the fields pickin vegies, but i never told anyone else that tip. my favorite first thing to do on a 'new' tractor was oil and filter changes, and the old generator to 12 volt negative ground gm alternator swap. i have worked on many J.D., ct, mack,and cummins diesels, so i got the 88 diesel knowing that i would never have to do much to it besides regular maintainance. the only thing i have never messed with are glow plug circuits, and the cold start fast idle things. these navistars are the only thing i have seen them on.

 

its official. it now all works. the fast idle did not work this morning, so after lunch i went out with the needle nose pliers, test light, and jumper wire to do some trouble shooting. after checking that power was going to the sensor, and the solenoid was working i plugged it back in, and realized yesterday i only got 1 terminal in the connector. from being disconnected for the past 10 years or so, the plunger was sticky, so i gave it a good soaking with PB Blaster, and then adjusted it all the way out to just before the linkage. i now have a 900 rpm fast idle, and after 3- 4 minutes, it drops to 500 rpm.


thanks Dave, your the best.

 

Glad to be of assistance. Glad it is running right.