KOEO fuel pump continues running.
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Freshman User
Joined: Oct 2003
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From: north central,fl.
KOEO fuel pump continues running.
Looking for some help please, Got a 89 F-150 , I-6, dual tanks. Trying to find out what tells the low-pressure in-tank pumps to cut off when key is turned on, but not started. I know the pump should only run for a second or two. Whatever pump I select will not shut off. Is this a timed thing or pressure related? Does the computer shut the pump off? Thanks for any replies!!
Elder User
Joined: Feb 2003
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From: MN
It could be a fuel pressure regulator problem. If the spring inside fails, the fuel can be allowed to flow back to the tank at a lower pressure than were an electric pressure switch would cause the pump to cut-off. I'm not sure if there is an electric pressure cut-off on Fords for KOEO or if it is like a 2 second PCM controled activation to provide fuel for starting.I'll run it past my instructor tommorow. The electric pumps should be the high pressure variety. I hope this helps.
Last edited by natewoz; Nov 2, 2003 at 10:13 PM.
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Freshman User
Joined: Oct 2003
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From: north central,fl.
Thank you natewoz for the replies!! Spent all day working on this truck and just about had enough. So far I've got a new high pressure pump, fuel filter, pressure regulator,took the 6-port selector valve apart, and removed the rear tank today to have a look at that pump. Still have same problem. I did try a relay off my 87 Mercury(donor car, EFI 302/ AOD trans. to go in my 85 Ranger 4x4)Thi
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s car has fuel problems also though, but the relay was replaced shortly before I bought it. Will try to find the right relay tomorrow. If thats not it, you think the PCM is crapping on me? At least I'm learning about EFI fuel systems, should help me on the Ranger engine swap. Thanks, will let you know what happens.
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s car has fuel problems also though, but the relay was replaced shortly before I bought it. Will try to find the right relay tomorrow. If thats not it, you think the PCM is crapping on me? At least I'm learning about EFI fuel systems, should help me on the Ranger engine swap. Thanks, will let you know what happens.
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Joined: Feb 2003
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From: MN
The relay should swap with say the AC relay or anything under the hood that has the same #'s on it.
I need a favor too, how hard was removing the rear tank and how did you go about it. Mine leaks through a seam, so I have not filled it since spring. Thanks
I need a favor too, how hard was removing the rear tank and how did you go about it. Mine leaks through a seam, so I have not filled it since spring. Thanks
Post Fiend
Joined: Nov 2002
Posts: 9,987
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From: Memphis, TN
KNOTHEAD
Unfortunately, your truck's relays aren't interchangeable like natewoz's '93. Yours uses a specific relay for each function.
If you're confident with wiring, it's pretty easy to convert to the later Bosch-type relays, which are not only cheaper, but MUCH more reliable.
natewoz
Click my signature and look in the EFI Fuel Pump photo album.
Unfortunately, your truck's relays aren't interchangeable like natewoz's '93. Yours uses a specific relay for each function.
If you're confident with wiring, it's pretty easy to convert to the later Bosch-type relays, which are not only cheaper, but MUCH more reliable.natewoz
Click my signature and look in the EFI Fuel Pump photo album.
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From: MN
Thanks for the link, I know how to unhook everything. The reason I ask is may people have said that actual removing of the rear tank is a pain because tha tank doesn't fit through. Looks like yours just dropped out of the bottom.
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Freshman User
Joined: Oct 2003
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From: north central,fl.
natewoz, thanks for the info! Tried a new pump relay today with no luck. Still working on finding an answer.steve83, nice link!! The rear tank was'nt too bad but clearance was a small issue (along with black widow nests and lots of sand/dirt on top of tank) On the right side of truck had tailpipe in way, left side was filler hose extending over top of frame. Just took hose and carefully folded back to clear frame rail and dropped tank down on left side. Be careful around the gasoline!!!
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89 full size tank has 8 bolts drops down fairly easy but you really need a floor jack with a plte or plywood attached to jack to support tank nicely,,,unbolt it slowly lower it a bit till you can get to the top to unhook fuel lines and electric wires ,,,also going back in i recommend a little grease on the "filler" hose assy this way you can slide it around as needed