I have a 1986 F250 6.9L Diesel with a glow plug eating habit. I have replaced 2 sets (16) of glow plugs within the last 75 miles.

The truck had been running just fine for the past 2 months (when I bought it). On Monday the 17th of December I went to start it and it took a very long time to get it to turn over (I had to use Starting Fluid). When I turned it off after letting it run for 7 minutes, it was hard to start once again.

I removed one of the glow plugs and did a resistance check and found there was no resistance. I checked all of the glow plugs and found they were all open (no resistance).

Went to my closest auto parts (I live very far out in the country) store purchased 8 glow plugs, installed them and the truck started just fine (like it usually does). I drove the 30 miles into town, made 3 different stops (shutting the engine off each time) and the truck started just fine each time (it was warm).

When I got in this morning (first time I started it since returning from town) it would not start. I checked the brand new glow plugs and they were once again all bad (no resistance).

I am new to diesel trucks and I do not have any manuals (the shrink wrapped Chiltons manual I purchased has very, very little on diesels). I would appreciate any help on probable causes and what needs to be replaced to fix the problem.

Also, any information on the correct (or best) glow plugs to put in the truck would be greatly appreciated.

Looking forward to getting your help.

Thank you.

 

[updated:LAST EDITED ON 21-Dec-01 AT 11:45 AM (EST)]Maybe the glow plug relay is letting them heat too long. I'm not sure though

Les

 

>Maybe the glow plug relay is letting them heat too long. I'm
>not sure though
>
>Les


I was thinking along these lines, too. You could test for current coming to the glow plus & see if it breaks when it should. I know glow plugs are rated for a specific cycle - if your's are on longer than they should be they will fry.

OILBURNER

'02 PSD 4x4
'88 *******ized Suzuki Samurai rock buggy w/ VW diesel

 

the '84-86 glow plug relay was the worst one they ever built. If you look in a "haynes" manual it shows the difference in the wiring relays. Your best option is to replase the relay with a newer style, or better yet rewire the relay yourself to a switch on the dash. Thats what I did and it works beautiful. I have another '85 and the first time the relay glows the plug it stays on for about 7 or 8 seconds the second time it comes on it only goes for about 2 sec, just not enough. I live in Canada and -20c in the winter time and it always starts. I glow the plugs for 5 secs off for 5, on for 5 off for 5, on for 5 off for 5, on for 5 ansd start 'er up. Then because your relay doesn't have an afterglow relay, do the same for about 10-15 sec at a 3 sec interval. Don't let anyone tell you it doesn't work either. I'm still working on my first set of plugs since I bought the truck(5yrs and still going). During Jan-Feb I put in 10w30 and I was able to start it in -28c without being plugged in. Now that was in dire straits and I would never recommend doing it if not neccessary, its way too hard on the vehicle. Where I work the outside plugs don't come on until -15c, so you can trust me, it workks

 

I did something simular with my 89 diesel. I wired the glowplugs straight to a push button. I don't think that you are suposed to do this but it works great. I wouldn't get into a habit of using starting fluid on these things. I did once when my glowplug controller quit while in the woods on a logging job and the motor blew about a month later. Maybe a coincidence, but if you ever go out looking to buy one of these engines you will realize that it is better to fix it right so it will start on its own

 

Thanks for the help. I'll check out the relay.

 

Thank you for the information. I will check out the relay. My winter conditions are not as severe as yours, but I want my truck to run right. Besides a set of glow plugs are expensive.

Thanks again.

 

I read you have problems with your glow plugs. I haved owned a 1985 ford bin there done that? What I have found is the prolbem with the plugs you buy. DO NOT USE DELCO.BOSCH ARE THE WAY TO GO. 5 years and no prolbem. Be sure to check your time relay for correct timing.

 

[updated:LAST EDITED ON 03-Jan-02 AT 02:13 AM (EST)] ok push buton gp are the only way to go the relay is on pass frnder well with 1 red 2 orange 1 purple and 1 black the controler is right behind the cdr valve on the intake use a pushbuton to jump the purple wire with a 15 amp in-line fuse and only use beru gps bosh are ok but berus are better and stay away from autolites,chamions, and delcos like the plegue only hold the gps on for 12 sec max at atime as they are 6v and the power going to them is 12v they will burn and open the you will be in deep ****e yea opps forgot relay is ok unless you arced some thing which i doubt it is the controler which is crap

 

There are a few things that can cause that problem. One is the relay. The other is a temp switch on the front of the motor. One easy way to tell if the glow plugs are no good without taking them out of the vehicle is with a 12 volt test light. After you remove the wire connector from the injector(should be a spade type on the 6.9)Connect the clip to the positive side of the battery and touch the spade male connector on the top of the glow plug. If the test light lights up it is good. If you need any more help trying to get through this problem e-mail me and i will try to walk you through it step by step on testing the components...Purrvette(No Email Addresses In Posts!)

 

NO a test light is not best way to check the glow plugs. If you have a old amp gauge connect wires to each side. Connect one to the positive side of your batter.Touch the other to each individual glow plug and watch to see if there is draw on the gauge. As the glow plugs work as a dead ground.

 

why would my glow plug relay repeatedly click on an off????? having charging problems .is this the cause????

 

Its suppost to go on and off, its a relay.If your burning them out they must be staying on. Dose the light go on and off on the dash? Dose the light work?

Chet

 

thanks, the light does go on and off about every 18 seconds.