Hey Guys I don't know if this is the right forum or not I have an 85 F250 with a 6.9 that I just got and being new to diesels there are some things not making sense. The guy I got it from had a direct wire from the battery to a toggle switch to a switch on the injector pump. Here's the thing turn toggle switch on it acts like the ignition switch except for starter engagement, use the key to start the truck but after truck is running glow plugs still cycle while driving and some time you don't need to use the toggle. Any kind of help would be greatly appreciated or wiring configurations.
Thanks Bill

 

when you turn the toggle switch after starting, does the engine shut off? If so, that is the on/off switch. the glow plug system is controlled by temp sensors in the coolant system and should be activated with the key switch.

sometimes when the glow plug system goes goofy, some people have replaced that automatic system with a momentary action switch to heat the glow plugs. you might have a full on switch for this, and that may damage the glow plugs or the entire system.

a little more info about that switch and the operation of the key switch would be more helpful to provide information.

 

After I start the truck and flip the switch off it shuts the truck down but like I said it just goes from the battery to the black adjustable switch on the side of the injector pump. I replaced the wiring harness along the column and it started without this switch before and now it won't run without it. I'm just dumbfounded on this on. Bill

 

Looking over the radiator there are two terminals on the right side of the injection pump. The front one is the fuel shut off solenoid, the rear one is timing advance for cold starts.
The timing advance and fast idle should be controlled by a coolant temp switch located by the thermostat which is under the alternator.
The fuel shut off solenoid is controlled by the keyswitch.
The switch is located on the steering column near the firewall, there is a rod that runs up to the key that activates the switch. If the switch is out of adjustment, ON might not really be ON.


As far as the glow plugs go, the 86 and earlier glow plug system was great, right up till it started to go bad. Then it was a nightmare. When mine failed several years ago, It would start to come on driving down the road. Then one day it came on and never went out. Toasted all the glow plugs when it did that. Here is the story on the 6.9 glow plug system.
The controller is located in the rear of the passenger side head. It is expensive, and in a very hard place to get at to change.
Since it has been in there for 21 years, it will probably break of when you try to remove it. If it does, you have to take the head off to stop the coolant leak you will have, that is not a good thing to do either.

The easiest and safest thing to do is mount a momentary switch in or under the dash somewhere. Now fine a power sorce that is switched with the key in the fuse box. Run a power wire from the fuse box to the switch. Then on the other terminal of the switch run a wire out to the passenger side battery area. There is a relay mounted on the inner fender well the has a large red wire on the front terminal and two large orange wires on the rear terminal. On the engine side there is a small purple wire the just pushes onto the terminal, the terminal toward the fender is a small black ground wire. Remove the purple wire and install the wire you ran from the switch.

Now for use, if you found a fuse that only had power when the key was on, turn the key to ON. Now hold the switch On for 8 to 10 seconds to heat the glow plugs.
Let off the switch and start the engine.

When it is real cold, below 0, you may have to hold the switch down about 14 seconds before it will fire if you do not have it plugged in.

The neat thing about the switch is, if you run to the store and shut the engine down, when you come back out you can usually just start the engine without the glow plugs. This saves them for when you need them.
In the summer I usually did not need glow plugs at all.
In the spring and fall when the temp was above 40 I used the glow plugs for the first start of the day and again if the truck set all day without running. If it was running every couple of hours I never used them.
When the temp falls below 20, if the engine is not running for more than 1.5 or 2 hours you will need them to start it every time.

 

I got my manual switch rigging plans here,works real well.
Saigon

http://www.members.shaw.ca/k2pilot/G...%20diagram.jpg

 

Well guys I figured it out. It is the fuel cut off solenoid, there is a wire that has been cut and I don't know where it is suppose to go this is the one that has the toggle switch from the battery without it I have no juice to power anything I've replaced the ignition switch. Like I said turn the switch and nothing I don't even get headlights flip the toggle and I get everything does this have to have a complete circuit and it acts as if its staying fully energized when there is power to it. Can this be replaced or repaired is my next question. Thanks Bill

 

Man this sounds like a serious wiring butcher has worked on your truck.
Most of your problem is probably located in the area behind the passenger side battery.
That is the stock power distribution point on these trucks.
Usually the battery is connected to a starter relay and has several other wires on the same terminal to power the lights, cab power circuit, glow plugs and alternator.
Yes it can be repaired, but it is going to take some work to figure out what has been chopped and rerouted.

 

Thanks Dave thats a good starting point I'll try to post pics as I do this and try to find aother truck to use as a guide that way if someone else get this nightmare I can help. Bill

 

You might check to see if they added an electric master switch . Basically this would be a continous solenoid . It looks just like a starter solenoid .

 

There is one main wire that powers pretty much everything . It is located on the passenger side fenderwell . They could have tied into it . Mine lost contact in the plastic wire connector once . It was quite a ride in the dark . I found the problem while I was on the side of the road . I just started wiggling wires untill I found the bad connection . .

 

One more thought . Could be that wire lost contact and they by-passed it insted of finding the problem . On my 86 it is a big yellow wire that goes into two smaller wires .

 

Both my trucks have the momentary switch Dave has described . Works great , only way to go .