Newby's ID won't start

[firsttimediesel]

This is my first post, so be gentle.

Went to start my 1985 F-350 today - the glow plug indicator flickered and died - and the truck wouldn't start.

I had been having some problems with the glow plug indicator light not lighting when I turned to the ignition, but up to this point all I did was to turn the key back to accessory then back to ignition and the light came on. This never failed to start the truck.

So what's up? Any experts out there today. Please let it be something simple.

Thanks in advance

 

[Mr_Roboto]

Most likely the culprit is the glow plug controller which screws into the drivers' side head. It's a simple bi-metal element that tends to fail.

First thing, check all your connections to make sure it isn't something simple. There's the controller on the head, and there's the actual solenoid on the passenger side fender apron (not the starter solenoid which is mounted on the fender itself).

You can wire a manual control of the GP solenoid, I've never done one for a 6.9 so someone else would have to give the wiring specs.

You should be able to jump across the 2 large terminals of the GP solenoid to energize the GP's to start the truck. Use a heavy screwdriver and hold it across for about 6 seconds. Again, NOT the starter solenoid which would crank the engine and run you over if you have a manual trans in gear.

 

[firsttimediesel]

Thanks. You wouldn't have a picture to post so I can get a better idea what it looks like would you?

 

[shorthair]

when i added a manual gp switch i just added a second ground wire to the controler with a push button & can now have my gp's lite for as long as i need though i dont go past 12 seconds.

 

[Mr_Roboto]

I know with the 7.3L controller all you need to run is a ground wire. I believe there is more involved with the early 6.9L system which is different.

Sorry, no pics. The 6.9L controller is the furthest thing back on the drivers' side head with a bunch of wires coming out of the top. The solenoid is - well - the only solenoid on the passenger side fender apron. Two bigger wires, two smaller wires.

 

[akoldnav]

Zig from this site has a really good design for bypassing the glow plug controller on the 84-86 models. The link for his design follows:
http://www.members.shaw.ca/k2pilot/Glow plug controller bypass diagram.jpg

I did this for my 84 and I was really pleased with how well it worked. The modification is a lot cheaper than the controller, but one must be carefull to not allow the glow plugs to stay on longer than about 8 seconds.

I hope this helps.

akoldnav

 

[firsttimediesel]

Thanks guys. I have enough information now to either fix my problem, or light myself up in the process.

 

[sle2115]

You could probably do a test using the block heater as well. I say probably because I believe it was in 85 when they went to the block that has more meat around the block heater and doesn't crack from using the block heater.

Good luck, and I would try jumping the solenoid as recommended. I would shoot a picture for you but I have the 87 system which is the solid state and the same as the 7.3. If jumping it works, a manual switch is the easy fix or if you want to get real deep into it, you could convert it to a solid state system! Get it started first and make sure the controller is the issue, but I think they are usually the cause if all the connections and such are good and clean. Might try unplugging and plugging it in a couple of times as well.

 

[Agnem]

Zig from this site has a really good design for bypassing the glow plug controller on the 84-86 models. The link for his design follows:
http://www.members.shaw.ca/k2pilot/Glow plug controller bypass diagram.jpg

I did this for my 84 and I was really pleased with how well it worked. The modification is a lot cheaper than the controller, but one must be carefull to not allow the glow plugs to stay on longer than about 8 seconds.

I hope this helps.

akoldnav

8 seconds could be way too short in cold weather. You can go as long as 16 with Beru's, but that is an ACCURATE 16. Not this one onethousand, two onethousand stuff. And you only do it once, with no after burn. The factory controller with usually go for about 12-14 seconds.

 

[akoldnav]

Mel, I was always afraid to exceed 8 seconds, so I would repeat the cycle after a few seconds off. Thanks for the info.

akoldnav

 

[Agnem]

In the summer 8 seconds is usually fine, and probably for folks with Autolites, probably 8 seconds too long.