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ENGINE FUEL PRIMING
If an engine is starved of fuel it will stop. If more fuel is added to the tank it is unlikely the engine will restart on its own.
Knowing that I decided to learn how to prime either an 8V92 or a Series 60. What makes me bring this up is during the Detroit presentation at the Tradewinds seminar the folks from the local Detroit dealer announced if you do starve an engine of fuel they will come out and prime it for $700.
If you are in the unfortunate position of finding you have an engine that will not run because it was starved of fuel keep reading because I am about to save you almost all of that $700.
Fuel priming on our diesels requires fuel to be contained from our fuel filters, all the way through to the engine, and then back out of the engine through the return line and back to the tank. It is something you can do if you are willing to get a little dirty and do a little running in the toad to get a couple of items.
The first thing to get is a pump up sprayer at any store that has these on sale. They are used to spray weed killer, pesticides, or other liquids around the yard or garden. Get one with a long hose or pick up some hose or tubing so you can add length to the hose on the sprayer. 5 feet will do, and make sure the capacity is at least 2 gallons.
Fill the sprayer with diesel.
You are now ready to prime the coach engine so it will restart. On an 8V92, with the rear doors open there should be a fuel filter mounted to the left as you look at the engine. The filter base has a plug in it that is an allen screw. Remove the plug and insert a threaded fitting you can hook the spray hose to. A barbed hose fitting will work. I suggest you carry one in the tool box.
Connect the garden sprayer hose and start pumping up pressure in the sprayer. Keep pumping until the fuel in the sprayer is almost gone. Do not allow it to be gone because the sprayer will then be pumping air into the coach and that is why it stopped in the first place.
I stop the sprayer from exhausting the fuel and then pushing air into the bus fuel system by opening the sprayer top so the air pressure goes to zero. Disconnect the hose of the sprayer, replace the plug in the filter base and the engine should fire right up if sufficient amounts of fuel have been pushed into and through the bus.
For the Series 60 the process is the same, except the connection point for the sprayer is on the base of the fuel filter that is towards the rear of the engine (closest to the front of the bus, passenger side) and that filter base has a fitting in place with a cap on it that has to be removed. With the cap removed, attach the sprayer and follow the process listed above to push through the bus fuel system.
There are many ways to starve and engine of fuel. Obviously the greatest chance comes from running the coach out of fuel. A fuel supply line can have a hole or holes in it so the engine is sucking air and not fuel. A fuel filter can be clogged as a result of dirty fuel either in the tank from such things as algae, or water. In my case I had 100 gallons on the coach, but the driveway was so steep the fuel flowed forward to the aux fuel tank on my steep driveway and at that point the fuel pickup was sucking air.
Be prepared by taking a few minutes to understand what I am describing and try to have the tools and or fittings to get fuel from a garden sprayer into the fuel systems.
Or you can just call for roadside service and be $700 poorer.
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19 Replies
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Thanks Jon. I have never changed a fuel filter or filters out but if I ever run out of fuel or get in a bind this is good to know. We all ain’t like Harry with gazillions in the pocketbook.
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And you would run out of fuel for what reason?
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Now Glen that’s a terrible lie… I never Cary a pocketbook! Thanks Jon, great information!
That reminds me Jon, If I use my Roundup sprayer will it also kill anything growing in my tank?
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Harry, go stand in the corner for a time out.
Glen, if you don’t change fuel filters and they get plugged you may end up testing what I just posted.
Tom, I have starved two buses out of fuel, and neither were out of fuel in the tank. The first was after refueling in OK we were westbound in NV and the bus engine started bucking and then losing power. Had I not been able to coast into a truck stop with the engine at idle the engine would require a prime. The fuel from a no-name cheap fuel truck stop on OK had dirt in it, and I changed all three filters (Racor and 2 spin on) at the fuel island and used the pump at the island to fill the new filters with fuel.
I’m not suggesting priming an engine is a common event, but if it should be needed we can do it ourselves if we want to save some serious money.
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Jon,
I hope you don’t mind I add some other options. In our previous Eagle we had a 6v92. I had a faulty fuel gage early on in ownership & ran out. I did have to get some fuel with the toad & a borrowed 5 gal jug to get 10 gals of fuel in the tank. For whatever reason I kept a gallon jug of diesel on board & pulled the filter plugs & filled them by transferring some fuel to a dish washing soap bottle. Don’t forget to have a small funnel around. I then removed the downstream connector to the 2nd filter (closest to engine) & used the dish soap bottle full of fuel to fill the line while having someone crank the engine. Once running I quickly reinstalled the fuel line & it kept running. If you don’t want to keep a fuel can on board use a siphon hose (especially if you know how to do it with your thumb not mouth) & fill the dish washing soap bottle a few times to fill up the filters & then go to the line.
A friend installed an electric fuel pump in line on his 8V92 just in case this ever happened. He uses the pump to fill the filters & line.
And of course if you don’t feel mechanically able or don’t have any of the above options now would be the time to call Coachnet or Sams roadside & they will get you the help you need. Jon I know you are not into the roadside assistance insurance but not everyone is as knowledgeable or confident in their abilities to handle even what seems to be the small things. Good Luck all!
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Good tip John. As to roadside assistance my greatest concern is someone unqualified working on a coach, or worse, intimidating an owner into getting a tow when the repair might be as simple as caging a brake.
I know of one owner that got towed and sustained serious and expensive damage when all he needed was a belt to the fan gear box. I don’t need to be on the side of the road arguing with a guy that thinks I own a bus, that I don’t work on one or understand one.
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Very good point Jon. It’s a shame that someone would do that to us undeserving folks.
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Very good information, Jon. You can also use a Siphon Spray gun if you have access to air.
It is handy for a lot of things and easy to keep on board. You can stick the siphon hose right down into the portable diesel can. It will also prevent Harry from spraying fertilizer in his diesel tank and diesel on his flowers.
Davy
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It does take a little pressure to push the fuel through the filters, engine and into the return line. But if it works that would take up very little space. The air would have to come from the aux compressor pressurizing the accessory tank.
1984 96" with 8V92TA
(remodeled Liberty Coach)
Greenwood, MO -
Thanks for this post, Jon. I just had a shop replace a couple of fuel hoses because I didn’t know if I could get it fired up again after. This procedure is going in my emergency repair notebook.
NOTE TO SELF: make an emergency repair notebook
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I forgot to mention, Jon, that we removed the main line coming from the fuel tank as it goes into the primary filter and filled the line from there. The filters were full and everything fired right up.
Davy
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As long as an engine has fuel at the injectors, and there is enough fuel within the system to keep it running for a while priming is not required. But if it is sucking air it ain’t going to run.
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Once upon a time at the Flying J in Gillette, Wy. after fueling I pulled to the end of the parking lot for the night. Caught a ride with friends to the local Western Sizzler for some grub – about an hour – left the coach unattended. – Should have had a enough fuel to make it home – but ran out of fuel in Bumf@@# Iowa. Exactly 100 gallons short at $4.12 a gallon. Bummer– gauge was telling the truth – but I knew better Ran out of fuel at a rest stop.
And to add insult to injury I had road service guy put 10 gallons in the tank went less than a mile to the next truck stop and pumped in 215 gallons into a 208 gallon tank that had at least 10 gallons in it. Go figure.
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You can also take your fuel filter off, fill with regular transmission fluid, and most engines will pick it up. Much easier.
Trans fluid doesn’t hurt anything.
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Transynd at about $40 per gallon, diesel at about $3.10.
Hard choice.
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