Hello, I had a question about my new 1986 F-250 with the 6.9L. When I bought it, the owner told me that the glow plugs no longer cycle automatically with the key in the proper position. He told me that I needed to jumper the terminal in red to +12V on the battery to cycle the glow plugs for about 10 seconds. Apparently, there is an open in the purple wire circled in yellow. He also mentioned a glow plug controller on the fire wall behind the air cleaner. Does that need to be replaced?


How can I fix this? I've done some research on the site and found out how to test the glow plugs; however, I know they work.


https://www.ford-trucks.com/forums/8...ml#post7434694


I can use this trick and I hear a click. After waiting 10-15 seconds the truck starts fine.


I would also like to check the glow plugs to see if they're Motorcraft. Do I have to pull the glow plug to see the part number / manufacturer logo, or do I just need to clean off the top of the engine with some engine degreaser and an old toothbrush? I hope they aren't Autolites!


Thanks for your input.

 

Could be your Glow Plug Controller that has gone south or the GP Relay.
There are Fuse able Links that could also have blown.


Did you read this Stikie at the top of the forum page for your year truck?


https://www.ford-trucks.com/forums/9...old-style.html


One of the big guns will be along shortly to give the right answers.
The one`s on my 86 have totally quite, just used the Block heater all winter to keep me going and starting.
Iam just hoping mine are not Autolites also.




Charlie

 

Charlie, thanks for sharing the link. Apparently I'm blind.


The instructions provided by Festus at the end of the thread seem pretty straightforward. I guess I should get testing.

 

if the truck is starting when you activate the glow plugs, they most likely are not autocraps. i have never see an autocrap glow plug work for more than a week at most.
they usually burn out within 2-3 starts.
the champion, ac delco, and wellman plugs are not much better.

 

I'll make sure I use the Motorcraft plugs if I ever need to replace them.