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| | | 1988 E350 fuel pump | Joined: Aug 2017 Posts: 5 stranger | OP stranger Joined: Aug 2017 Posts: 5 | I have the dual tanks and I believe a bad fuel pump. The motor turns over but does not fire, fires when I use starter fluid. Does this van have one inline pump or pumps in both tanks?. It is the 5.8l 351.
Thanks in advance, Steve
| | | Re: 1988 E350 fuel pump | Joined: Sep 2005 Posts: 9,855 Likes: 234 carpal tunnel | carpal tunnel Joined: Sep 2005 Posts: 9,855 Likes: 234 | You have three fuel pumps. There is a low pressure pump in each tank. They are controlled by the switch on the dash board. The transfer valve (unlike older models) is not electric. It is pressure operated. When you use the switch to choose a tank (front or rear) the pump in that tank operates and pressure from it causes the transfer valve to swap over to that tank allowing fuel to pass on to the high pressure pump. These in-tank pumps normally put out only about 4 to 8 psi. The high pressure pump is located on the drivers side frame rail just about under the drivers floor board. It is in the fuel line after the transfer valve. The replaceable fuel filter is located there as well. The high pressure pump will put out anywhere from 40 to 60 psi to the fuel pressure regulator. The fuel pressure regulator is located on the drivers side fuel rail. It is controlled by manifold vacuum and passes the unused pressure back to which ever tank is being used via the fuel return lines. 1. You should be able to hear the pumps run for a few seconds when you first turn the ignition switch to the run position. After the engine starts the ECM will look for a signal from the distributor to allow the pumps to run. If you don't hear them, or only faintly hear them, start checking for power at the high pressure pump connector. Remember it will only be there for a few seconds if the engine isn't running. 2. Has your van been sitting for a while? If you get rust in the tanks it will clog the transfer valve and cause the high pressure pump to run dry. The transfer valve swaps both tank supply lines and return lines so it has four hoses on the tank side and two on the engine side attached. It also has a fine screen inside which is usually not serviceable if it becomes dirty. I have taken them apart but they will sometimes leak afterward. The transfer valve is mounted inside the drivers side frame rail just about under the drivers seat area.
Hope this helps.
Last edited by CatFish; August 25th 2017 6:52 am. Reason: kant spel
| | | Re: 1988 E350 fuel pump | Joined: Aug 2017 Posts: 5 stranger | OP stranger Joined: Aug 2017 Posts: 5 | Here is what I know so far. When I turn the ignition key to the on position (not cranking) the pumps do not receive power. If I bridge pin 30 and 87 on the fuel relay I hear the pump in the tank (works on both tanks) I tested the EEC relay and it is functioning, also tested the inertia and it works. What's next?
Also, if I use starter fluid the engine fires up for a second so I know I have spark. I have been trying to chase wires to find a break but I am at a loss.
Yes, it has sat for a while. I plan on dropping the tanks and cleaning them.
Last edited by Smull; August 29th 2017 4:57 pm.
| | | Re: 1988 E350 fuel pump | Joined: Aug 2017 Posts: 5 stranger | OP stranger Joined: Aug 2017 Posts: 5 | Problem solved! The ground for the EEC Relay had come loose and was touching a + wire, shorting out the relay.
She fired right up after that. | | | Re: 1988 E350 fuel pump | Joined: Sep 2005 Posts: 9,855 Likes: 234 carpal tunnel | carpal tunnel Joined: Sep 2005 Posts: 9,855 Likes: 234 | Groovey! Daddy always said to trace the grounds first... We've owned our '88 E150 Hi-top for 26 years now. | | |
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