priming fuel pump ???
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priming fuel pump ???
ok today my wife had this prob she was at work with the truck went to turn it on and the truck would try to turn over but would not start. she had fuel ,battery was good and all, so we thought it was the fuel pump, so I had AAA go down to pick up the car but the guy moved the switch back and forth from the off to on position to prime the fuel pump and it turned on. does this mean the pump is going??
Post Fiend
Joined: Feb 2003
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From: Eastern WA
I've never actually seen such a problem, but then again I have no clue what you are driving 
. If it's somewhat modern and thus has EFI, maybe the check valve in the fuel line (pump, but don't know what you're driving) is going bad.
. If it's somewhat modern and thus has EFI, maybe the check valve in the fuel line (pump, but don't know what you're driving) is going bad.
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Joined: Apr 2004
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From: State of Misery (Missouri
Originally Posted by gabebdog1
ok today my wife had this prob she was at work with the truck went to turn it on and the truck would try to turn over but would not start. she had fuel ,battery was good and all, so we thought it was the fuel pump, so I had AAA go down to pick up the car but the guy moved the switch back and forth from the off to on position to prime the fuel pump and it turned on. does this mean the pump is going??
Does that mean you checked for fuel at the bleeder and for spark at the plugs?
When you say the AAA guy moved the switch, which switch? I am assuming he moved the "bump" switch, that is supposed to pop off when you get hit, or a big enough jar to trip it. These do false trip, but normally if you have to hit the switch, either the switch is going bad, or you've had some kind of jarring experience.
Postmaster
Joined: Jul 2005
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From: Abilene, Texas
I think he meant turned the key on and off to prime the fuel line. If that is what you had to do then bill is probably right. The pump (or the line depending what truck) has a check ball that is supposed to be one way. It holds fuel pressure, from the tank to the engine, so that when you go to start it there is fuel already there and it dosent have to pump it from the tank to the engine. Thus giving you a quick start without having to prime the line. If the check ball is bad then it will leak the fuel out of the line back into the tank. Causing you to have to prime the line to get it to start. GL
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Originally Posted by texans
I think he meant turned the key on and off to prime the fuel line. If that is what you had to do then bill is probably right. The pump (or the line depending what truck) has a check ball that is supposed to be one way. It holds fuel pressure, from the tank to the engine, so that when you go to start it there is fuel already there and it dosent have to pump it from the tank to the engine. Thus giving you a quick start without having to prime the line. If the check ball is bad then it will leak the fuel out of the line back into the tank. Causing you to have to prime the line to get it to start. GL
Postmaster
Joined: Jul 2005
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From: Abilene, Texas
if your pump is the kind with the check ball in it. Then yes you probably need to check it. You can hook up a pressure gague to the fule system (I think there is a fuel rail for this on the engine). check your pressure when you are running at idle. Then when you shut it off watch the pressure it should hold. leave it hooked up over night, and check it in the morning to make sure that it is still holding. If it has droped then that would tell me that you have a bad check valve.
Post Fiend
Joined: Feb 2003
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From: Eastern WA
Last I heard the check valve is part of the pump. To get to the pump, remove the bed rather than drop the tank; it's much easier this way. There's a few bolts that hold the bed to the frame, the wiring harness to unplug or remove, and the gooseneck between the tank and the filler cap. Have a buddy help you remove the bed.
**BTW, if it passes the pressure test noted here, we next will want to talk about the possibilty of a bad EEC or FP relay. This is especially true if your no start problem is intermittant. Also, when doing that test, make note of what the pressure is in the morning, with the key on, but before starting it.
**BTW, if it passes the pressure test noted here, we next will want to talk about the possibilty of a bad EEC or FP relay. This is especially true if your no start problem is intermittant. Also, when doing that test, make note of what the pressure is in the morning, with the key on, but before starting it.
