I'm new to the site and i got an 85 F250 with the 6.9 idi. I've owned the truck for about a year and it keeps burning up glowplugs. I bought it off a farmer and i notice that he had the controller bypass. Could that over energize the circiut and cause the problem.

 

The controllers on the 6.9 are notorious for failing. So is it setup for manual control(I assume thats what bypass meant), if so, how long are you running them? You want to keep the glow time to about 10 seconds.

 

I'm running them for 10-15 seconds above 50 degrees. Below that i run them about 20 seconds.

 

Um, no more than 10 sec. If it's really cold, like below 0, no more than 8 seconds between cranks. Then once it's running, 3 second bursts ever 5 seconds for a minute.

 

Thanks for the helpful replies.

 

Does it fire off on the first try??

 

yeah it usual fires on the first try.

 

Was going to say, no other reason to run the glow plugs that long.

 

Well when its really cold when it misses when it fires off. I hold them to help it fire on all eight.

 

what brand of plugs are you installing. if you wanted to keep doing what you are, wellman makes dualcoil glowplugs that can be held on for a max of 15-20 seconds.

only run motorcraft or buer glowplugs. do not run autolite, bosch or any other cheap brand. they will swell the tip and possibly break the tip off. once the tip breaks off, you will have to pull the head. these engines can not pass the tips. when the piston is at TDC, there is only enough room between the piston and head for 7 sheets of paper.