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Air in Fuel
We have a 1997 XL Parliament conversion that we are trying to track down an air leak in the main fuel line coming from the fuel tank. Able to make bus run fine from auxiliary fuel tank plumbed to primary fuel filter. Air and lots of it, is present in a clear line when pulled from fuel tank with a hand pump. Can someone please help with where the fuel lines run from the tank and where the fuel pick up is located? Has anyone had any problems with the fuel pick up leaking air? Thanks for any help you can give. Ric and Jane We will be on cell if anyone has any thoughts 612-875-1881
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12 Replies
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Typically if it were the fuel pump, it would be all the time and you would not be able to prime the engine and get it running, nor would it go down the road….I would suspect that the fuel is bleeding off via a leak or crack in a fitting…
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What is the status of fuel filters ? Are fuel line gate valves fully open ?
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Yes. Good Sam sent mech they got it started the first time../. charged me 280. I drove 100 miles had oil changed and now it is down again… can I pressure tank again or can this cause other problems.
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15psi is way too much pressure to put into the fuel tank. Multiply that with the area of the fuel tank that is exposed to air and you are putting thousands of pounds of force on the fuel tank walls. You don’t want to split your tank seams.
A few psi is all that is needed to help prime the engine. Just wrap a rag around your air line to temporarily seal the fill opening.
Make sure you have the proper fuel filters and that they are well seated. Check for double gaskets. One of the truck stops put the wrong filter on our bus and I had the same issues.
As Jeff says you have a vacuum/air leak in the fuel supply.
Gerald
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Thank you …very much… if I get it started I will have the code read for the check engine light… I hope this will find the problem….
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FWIW…if you take your bus to a diesel repair shop in the USA the first thing they will do on a fuel problem is filters.
It makes no difference if you just changed them an hour ago….Inspection and replacement of you’re existing filters, gate valves, fuel lines within 6 Feet of your engine. Most often cutting open the existing filers to find any clues.
Filters protect your engine from many problems….that’s why you have 2
AL
Good Sam…..really ?
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What about the check valve in the fuel line, I think your vintage has one.
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Does your model year have the check valve at the rear of the head on the return line? That could also be a problem. I had a loose injector that allowed compression into the fuel rail which pushed all the fuel back to the tank.
How long does it have to be shut off before it won’t start, or does it do it no matter how long it is off?
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Your Detroit S60 should have a check valve on the fuel line comng out of the head of the engine. This will be at the rear of the engine as it is installed in the coach.
Ideally fuel pressure is held in the fuel galley of the engine head from the check valve inthe fuel pump to the check valve on the rear of the head. It would be more reasonable for the check valve to be faulty than the pump.
Do you have a Racor or Fuel Pro filter system on your vehicle? They have a check valve in them also and can cause loss of priome but usually over a longer time period.
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Very solid! If they don’t cure repost and I’ll walk you thru how to get to fuel line etc. One bad place on your coach is behind where start batteries are. Make sure it hasn’t arced to batt. = small hole. Ch fittings at filter—Do the other suggestions first. If tank was pressurerised look for wet place on line.
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will it keep running if you press engine overide button?=bad sensor
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The override switch on the Detroits is for use when one of the three sensors for engine shutdowm fail or are a problem. The engine shuts offs for high engine temperature, low coolant level and low oil pressure. If one of these fail yoiu can push the override and you get the engine to run for 60 to 90 seconds more. You can push the override as many times as you like but each time is registered in the engine computer.
If your problem is losing prime on the fuel system, then I do not believe that the override is going to do any good.
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