AFAIK, unless someone changed something, there is no inline fuse, but there should be fusible links right off the starter relay at the fender. I think its two paired wires that feed the glow plug relay and each wire has a fusible link.

Unless you pull out BERU/Motorcraft glow plugs at the junkyard, you'll be wasting your time and money. Honestly, trying to use junkyard glow plugs is wasting your time. Buy the new ones, they last a VERY long time.

If you don't have a GOOD quality multimeter, you won't get a useful reading. As mentioned in the glow plug thread (which I hope by now you've read) it can be hard to get a reading with a cheap meter that means anything.

Good luck on the injector line. I would get the entire set at the junkyard, just in case another goes. Its odd that they'd break by the pump, usually people have issues at the injector side. There is a good chance you'll have to pull several lines to get access to the bottom one thats busted. Just take your time and be careful and it shouldn't be too bad. Also make sure all brackets that hold the lines together are put back on. They keep the lines from vibrating which can cause failure.

 

Also, I believe lines from a truck and van are the same, except for #1 and #4 which have the timing adapter on top of the injector depending on application (#1 for trucks, #4 for vans if I remember correctly).
But, a truck line for #4 would work in a van if you took the timing adapter off, and vice versa for a #1 van line in a truck.

Lines from a 6.9 are very similar, but slightly different, although I believe they will still work on a 7.3, at the very least a complete set would work.

 

So your saying that a line 4 from a truck would fit line 1 on van? Tell me what I need. I'm replacing line 1 on a van style.

 

Ok looked some more. Tell me if I'm wrong... driver side is 1.3.5.7 from front back. Passenger 2.4.6.8
From reading I may have been wrong. The line I'm replacing is farthest forward on the driver side

 

Hey idiguy. Like me, you are on the journey of discovery with these classic old trucks. I see more than one reply encouraging you to read the stickies at the head of this forum, and I endorse this. Get to know your engine and systems by reading, reading, reading, print the material if necessary and track the info physically by comparing the information to what you see on your truck. Many of your queries will be answered in this way, most of the replies are from very knowledgeable and experienced guys encouraging you to be thorough.
Very early in my ownership of the f100 I have I found out the limits of my fuel gauge, running out on a minor freeway. The bailout I got from our Automobile Association included startup, for which the guy insisted on using ether. He did use a very small spray, and grumbled because I waited 30 seconds before cranking. My glowplugs are on a manual system on a timer, I believe the quantity of ether you will use will increase gradually, ruining your engine, instead of a small investment in time and money for the repair of your glowplug system. I would buy another of these trucks tomorrow for the price you paid, I have 5 diesels of differing makes already, wouldn't dream of using that street stimulant on them. All the best.

 

I think I have a fuel system problem as well as it is 75 degrees and it won't start without ether so once my leak, return lines and that is done I'll look into glow plugs I'd think they would be unnecessary in this weather. Probably a compression test in order to.

 

Nope, still need them. Just fix them already man Get you some real plugs (Beru/Motorcraft) that way you remove a huge variable from the equation.

And like the man said, read. Read. Read.

 

anything under around 90 degrees block temp is going to give you a bit of trouble cold starting. the glow plugs work until the block coolant temperature reaches around 110 degrees.

 

I've got Motorcraft and I did the light tester connected to positive and put tip on glow plug and they all lighted. So relay? The plugs don't look that old.

 

No... I think I said too much there and it was confusing.
On trucks, the timing adapter is on top of the injector for cylinder 1. Thus line 1 is shorter to compensate.

On vans, the timing adapter was moved to cylinder 4, to make it easier to reach (from the doghouse side I guess) since the front of the engine is buried under the cowl. So on vans, line 4 is shorter.

So if you need to replace line 4 on a VAN, you could remove the adapter and use line 4 from a TRUCK.

If you are looking for line 1 for a VAN, you could use line 1 from a TRUCK... but you would have to take the timing adapter from the truck to put back on injector 1 in your van to make the line fit. Or just get the correct line from a van...
I believe the timing adapters may only be on 7.3's? when they switched to using the piezo probe instead of the luminosity method for timing. 6.9's might not have the timing adapter, in which case the lines for vans and trucks would be exactly the same.

 

Also, test lights aren't the best indicator for glow plugs. A test light is only a test for continuity. A shorted out glow plug will light up a test light, but not have enough resistance to glow.
Since you don't actually know if they work, I would pull the glow plugs and test them with a battery charger to see if they heat up and glow. It shouldn't take more than a 2-3 seconds for the whole tip to be glowing. (ok.. the area right next to the threads might not glow, but the rest should) I know there are videos on youtube of people testing glow plugs if you want to see what they should look like.

It really shouldn't take you too long to pop them out, test them, then pop the working ones back in. That way you'll know for certain if they work, and if they definitely are Motorcraft/Beru plugs. If they all work, then look at the glow plug relay/controller. I know the stickies have all the details on testing them, I've never gotten that far, just had to swap out bad glow plugs on my '88.

 

Ok after my Motorcraft glow plugs passed like every test (and I read the links!) I found the battery power to my relay was like .65-1.75 with multimeter. In line fuse has 700 resistance as well.

 

what inline fuse? there should not be a fuse in the glow plug circuit.

 

The lines from the battery that feed the glow plug relay. There is a fuse between there.

 

shouldn't be.
if anything it should be a fuseable link. a fuseable link is designed to burn out if ovrloaded, but it is more like a slow blow fuse, not a fast burn like a regular automotive fuse.