1974 King International Firetruck

[Jack1]

Hello to everyone on this forum'

I was wondering if I could get some help here' I have a 1974 King International Harvester Firetruck and I was driving it up one of my hilly roads and it was low on Diesel fuel' It quite on me half way up the hill and now it won't start' I filled the tank up with diesel fuel but now it has air in the system. This truck does not have a primer pump and I can't see the fuel rails or injectors on this motor so I can't crack the lines at the injectors to let out the air. One thing I know I have against me is it's half way up a hill so the fuel tank is lower then the motor. What I have tried is sucking the fuel up to the two fuel filters and I tried pumping fuel up the line to the pump. I filled both fuel filters and cranked it over about 4 times and then fill the filters again and crank it over. I did this about 15 times' when I first crank it over it tries to start for a second and then just cranks. There has to be air still in the lines but I can't see the injectors to crack the line to let on the air. Is there an easier way to do it because I don't know what to do now.

Any help would be appreciated.

Thanks, Jack

 

[DB2]

Any way you can get some air in the tank and pressurize the system? Or post some pictures so someone can show you where to bleed ?

 

[Jack1]

Hey DB2 thanks for the quick reply.
I only have a couple pic's right now I will have to lift the cab back up to take some more.

 

[DB2]

A Detroit. These can be very problematic to start after being run out of fuel. I would fill the filters again if you can’t get an air pressure source to the unit. Then try and use some starting fluid to keep it running if it will fire. It all depends on how much of a panic you are to get it off of the road.

Someone else will likely have a better suggestion

 

[Wes J]

Those Detroits had unit fuel injectors, so there's not really any way to "prime" them like a mechanical pump.

If it has a lot of air in it, you can set up a pump to circulate fuel through the supply side until you get no bubbles on the return side. If you have a good fuel supply and a good battery, it should prime up on its own.

Maybe you lost the transfer pump.

 

[Jack1]

when I turn it over a few times then I pull the fuel filter off and check the level it's half full so I fill it up again so the fuel is going somewhere. One question I have ' when I pull off the filter' drop it down to fill up the filter with fuel am I letting air back in the system or not' Just wondering If I'm wasting my time doing that.
I have a full tank of fuel now and if I hook up a compressor to the fuel tank and pull off the return line and crank the engine will that fuel go threw the system and force the air out of the lines.

 

[old-iron-habit]

Detroit's will usually pop right off if you fill both filters with fuel. Your V6-71 should be no exception. Are the filters clean? Running the fuel tank on these old seldom run rigs, even close to dry, often picks up crap that ends up sloshing around in the bottom as it gets slopped of the side of the tank because of the splashing. Especially when they set without a lot of fuel in them. Change both filters and change the gaskets also. The second filter located after the pump runs at 60 PSI of pressure. The 60 PSI gear pump moves a lot of fuel but will also easily will suck air from around the first filter if the seal is not good. Often after filling them with fuel because of running dry, them old gaskets will not easily seal and they suck air.

 

[Wes J]

I don't think the compressor will work because the supply and return both go to the tank. You'd have equal pressure on both.

 

[old-iron-habit]

when I turn it over a few times then I pull the fuel filter off and check the level it's half full so I fill it up again so the fuel is going somewhere. One question I have ' when I pull off the filter' drop it down to fill up the filter with fuel am I letting air back in the system or not' Just wondering If I'm wasting my time doing that.
I have a full tank of fuel now and if I hook up a compressor to the fuel tank and pull off the return line and crank the engine will that fuel go threw the system and force the air out of the lines.

You need to fill both filters to have half a chance. Are they spin on or cartridge. On the cartridge ones the pre-pump one is usually twice as big as the post gear pump one. The spin on ones are often close to the same size but they are also different with different part numbers. Do not mix them up and use a low pressure one after the fuel pump.

Edit. Looked at pictures. Your sequence is tank in to first filter, out to gear pump, out of pump to 2nd filter, out of second filter to injectors. There is a 90 degree fitting on the block on the return. do not remove it trying to free up the flow. It is drilled an sized for your engine so it holds the right pressure for your injector size.

 

[old-iron-habit]

I have used a electric pump but it should not be necessary. I lost prime often on one once due to a bad fuel filter gasket. You could remove and plug the return line but don't put much over 3 to 5 lbs of air in your tank. A old inner tube with a hole cut out of it to clamp over the tank filler works well, Just put air in until the tube is partially expanded. Then you can bleed thru the filters and not have to try to hold air at the tank. If fuel comes out the secondary filter you should be good to go.

 

[Jack1]

The truck run good before I ran it out of fuel' I checked the filters by dumping out the fuel and no crap come out of it so they looked pretty clean to me' When I fill the filters up I can't see any leaks and they did not leak before

 

[Jack1]

You need to fill both filters to have half a chance. Are they spin on or cartridge. On the cartridge ones the pre-pump one is usually twice as big as the post gear pump one. The spin on ones are often close to the same size but they are also different with different part numbers. Do not mix them up and use a low pressure one after the fuel pump.

Edit. Looked at pictures. Your sequence is tank in to first filter, out to gear pump, out of pump to 2nd filter, out of second filter to injectors. There is a 90 degree fitting on the block on the return. do not remove it trying to free up the flow. It is drilled an sized for your engine so it holds the right pressure for your injector size.

Both filters are spin on' I have filled them about 15 times and it still won't start because there still must be air in the system.

 

[old-iron-habit]

The truck run good before I ran it out of fuel' I checked the filters by dumping out the fuel and no crap come out of it so they looked pretty clean to me' When I fill the filters up I can't see any leaks and they did not leak before

Yours may very well be sealing but you will often not see a leak on the primary if it is sucking air in. The filter is not full when it sucks a little of the top so no fuel will be dripping unless its pressurized when full. Just trying to cover all the possibilities. I have also seen the rear seal go out at the drive end of the gear pump and then they suck air at that point. I don't feel that is your issue as your tank was very low. If you had a half tank of fuel that would have been worth checking.

 

[old-iron-habit]

Both filters are spin on' I have filled them about 15 times and it still won't start because there still must be air in the system.

Should fire right up. Getting any fire at all? The Detroits are one of the easiest Diesels to prime. Still saying sucking air. I'll see if I can alert Kshansen to this post. He is a real expert.

EDIT: Corrected spelling on Kens handle.

 

[Jack1]

When I first turn the key it fires and then just cranks and cranks and then when I let it sit for 2 minutes and turn it over again it fires and then just cranks' It fires each time I first crank it over

 

[old-iron-habit]

You might try loosening the outgoing line on the second filter and crank it over . If both filters are full it should in short order throw fuel like crazy with no air spurts. That will insure you got no air that far. you should be good to go then. If it gets pressure to fire the injectors your pump is good. You still have or are sucking air into the system. Are you sure it ran out of fuel in the tank or maybe just real low. Wondering if the fuel line collapsed internally and closed it up. another long shot. On a 74 International I had, it flattened out right where it laid across the frame for 35 years or so and cut my fuel supply off.

 

[Jack1]

When I pull or unscrew the first filter to fill it back up where the tank line runs into the top of that filter' Since the truck is on a down grade and the filter is off will the fuel go back down the line into the tank again and then have air in that line. Just wondering

 

[old-iron-habit]

If you are in a pickle to get it off the road you could use a portable tank of some kind and set up at a higher elevation than the engine and let it gravity thru the filters. If you drive it that way you will probably need to route the return line to your can also because they return a lot of fuel and you will soon empty the tank. You might try that with supply only just to prime itand then hook the truck tank supply line back up.

 

[Jack1]

I think I ran it out of fuel because I know it was low and I had fuel in the back of my other truck to put in it. I got in a rush and forgot to put the fuel in the truck and I moved it up the road and when up a hill. That was a mistake. I will never do this again run it so low because it to hard to get it going again.

 

[old-iron-habit]

When I pull or unscrew the first filter to fill it back up where the tank line runs into the top of that filter' Since the truck is on a down grade and the filter is off will the fuel go back down the line into the tank again and then have air in that line. Just wondering

I have never had that problem. The tank is normally lower than the engine. The filter should still stay full and be adequate to start it. They circulate way more fuel than they use.