1988 460 engine cutting out
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1988 460 engine cutting out
Hello, I am a newbee to this forum .The question I have is on my 1988 e-350 class c motor coach .It has been sitting for about 2 years I put new gas changed the filters oil ect.... I first cycled the ignition about ten times to build up pressure from the fuel pump I could hear it humming. Then I started it and let it run for a little while sounded great then died its almost like it is starving of fuel . Would this have two fuel pumps because it is 30' feet to the back? If so would there be two fuel relays also? I also noticed while I was under the coach what appears to be another fuel filter way in the back on the frame rail by the rear axle so I opened it but no filter
? Any help would be great
? Any help would be great
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From: Easton,Ks
What type fuel system do you have (FI or Carb)?
I will assume that it is an 460 MFI engine.
The one in the back is the fuel selector valve and fuel reservoir for the high pressure pump forward on the frame.
You have three fuel pumps, one low pressure boost pump inside each tank and one high pressure pump on the frame.
This fuel system only has one fuel pump relay but also will have a fuel pump cut-off switch (Inertia Switch) and a fuel selector switch at the dash.
I am thinking this is the fuel system you have:
This electrical diagram below should be close to what you have:
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I will assume that it is an 460 MFI engine.
The one in the back is the fuel selector valve and fuel reservoir for the high pressure pump forward on the frame.
You have three fuel pumps, one low pressure boost pump inside each tank and one high pressure pump on the frame.
This fuel system only has one fuel pump relay but also will have a fuel pump cut-off switch (Inertia Switch) and a fuel selector switch at the dash.
I am thinking this is the fuel system you have:
This electrical diagram below should be close to what you have:
/
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Thanks for the reply subford but this diagram is what I have in my ford dually pick up .In my coach I have a single 30 or 40 gal fuel tank do I still have two fuel pumps ? The fuel pump is located right behind drivers front wheel with the filter behind that. Then following the frame rail just in front of the rear axle looks like another filter ( bowl type ) but no filter also no wires going to it then it goes to the tank. would the second looking filter be a dummy selector valve. If there is a pump in the fuel tank that is no good would that starve it of fuel even if I can hear the pump humming under the drivers door ? Should I hear a hum in the fuel tank ,how do you check a fuel pump to see if it is no good before buying a new one ? How long do they last? the coach only has 26,000 miles on it been in the family sense new.
Fleet Owner
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From: Easton,Ks
Yes, one high pressure on the frame and one low pressure boost pump in the tank.
You also need the in tank pump if you run out of fuel to prime the high pressure pump.
It is just a fuel reservoir for the high pressure pump forward on the frame.
It makes sure the high pressure pump has enough gas for WOT and hills.
Sometimes but it will run normal on flat land.
Yes you should be able to hear the in tank pump run from the filler or under the tank. You can also take the supply hose off where it goes into the fuel reservoir (the larger hose) and aim it in a bucket to see if it is running with the key on and pin #6 of the self-test plug shorted to pin #2. The low pressure pump puts out between 7-12 PSI with pin #6 of the self-test plug shorted to pin #2.
Do not let the high pressure pump run for more than a few minutes you may want to unplug it while testing the low pressure pump.
If you check fuel pressure with a gauge at the fuel rail you should get between 40 and 45 PSI with the key on and with pin #6 of the self-test plug shorted to pin #2.
Most of the time around 150K miles or 15 years.
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You also need the in tank pump if you run out of fuel to prime the high pressure pump.
It is just a fuel reservoir for the high pressure pump forward on the frame.
It makes sure the high pressure pump has enough gas for WOT and hills.
Do not let the high pressure pump run for more than a few minutes you may want to unplug it while testing the low pressure pump.
If you check fuel pressure with a gauge at the fuel rail you should get between 40 and 45 PSI with the key on and with pin #6 of the self-test plug shorted to pin #2.
/
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Thank you for your time subford this make more light on the problem I think that pump in the tank is shot . The holding reservoir for wot on hills was very confusing I have never seen anything like it . 88 dually the gas was 2 years old but it only was about 5 gals and it had stabilizer in the tank for winter storage. prior to putting in new fuel I put a couple things of drie gas in to make sure there was no water. Again I want to thank you for the help. I will drop tank and purchase a new fuel pump and filter .
PS.. should I replace the high pressure pump to seeing how it's 23 years old or just weight till it dies ...
PS.. should I replace the high pressure pump to seeing how it's 23 years old or just weight till it dies ...
Fleet Owner
Joined: Aug 2005
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From: Easton,Ks
I would get a one ans just keep it with you and change it out if it goes out on the road.
It is not that hard to change it and it does not take up much room.
But that is just me, as the new ones seem to fail a lot soon on me then the ones that came with the MH.
It is not that hard to change it and it does not take up much room.
But that is just me, as the new ones seem to fail a lot soon on me then the ones that came with the MH.
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I think that is a great idea i'll pick it up the same to and put it in the draw just in case .
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