No power at fuel pump

Sunk · Mar 19, 2008

A few days ago my truck started 'bucking' as if I was repeatedly stomping on the gas. It did it fairly intermittently, and not so much at higher RPMs. I read on here that it could have been the driveline binding so I was planning on checking that, but before I could, it died and now won't restart. I was thinking it was the fuel filter so I checked for pressure at the rail, and it had some, but after checking it a couple times and trying to start it after it sat, I had nothing. I checked the filter, that flows, the pump is good when power is hooked up to it, but when I checked for power on the leads at the pump, I got nothing. I had a friend listen for the relays clicking, and they're good. I was looking into testing the TFI, but Im not sure which test I need to do to check for this, the article in the Tech Library didn't really say much about fuel issues.

Maybe Im going in the totally wrong direction, somebody clue me in.

Sunk · Mar 19, 2008

I had a friend try to jump the jump the relay while I listened to see if the pump would turn on, and it didn't.

Jorley · Mar 19, 2008

The power for the fuel pumps run from battery to relay thru a fusible link and from there to the intertia switch then to the pumps.
Check that you have power to the relay(yel wire),if no power it's the fusible link.
If power is present,check wire from relay(org/Lt. bl)(with key on), if no power contacts inside relay bad.
If power is present,check the inertia switch(passenger side floorboard behind carpet next to tranny hump. If reset doesn't work, try disconnecting it and use a piece of wire to make a jumper.
That's the wiring for the fuel pump in a nutshell. If you know how to read wiring diagrams this site has them for your truck. Login and password is Library.
http://search.ebscohost.com/login.aspx?authtype=url,uid
Hope this helps with your problem, if it does or doesn't, post so we all know. BTW, don't forget to vote for TRS as the top 4X4 site.

Sunk · Mar 19, 2008

We checked the relay for power, and got 12V at one wire. My friend was using the multi-meter and after he found one wire with power, I don't know if he kept looking for another wire power.

We did this with the key off though, my buddy said it wouldn't make a difference, does it?

Jorley · Mar 19, 2008

The yel wire to the relay will have 12v all the time, the org/Lt. blu will only have power with the key on to activate the relay. If there was 12v on the yel wire, fusible link is good.

Sunk · Mar 19, 2008

Ok, well I think that means the fusible link is good(we were testing the rear relay, the black/grey one. I was never able to the two apart, only where they were located).

Jorley · Mar 19, 2008

I'm don't know the location or the color of the relay. You could check for voltage at the inertia switch. The two points are elecrically the same.

Sunk · Mar 19, 2008

I checked for voltage at the FPIS, but with the key off. I'll try it again tomorrow, and try resetting it. Thanks for the help.

Jorley · Mar 19, 2008

No problem. Post the results and don't forgt to votefor TRS as top 4X4 site.

Sunk · Mar 19, 2008

I always vote, I love TRS.

Jorley · Mar 19, 2008

I've only been a member since Feb. I went ahead and became a premium member when I registered because to me $10 is a cheap price to pay for the info have gotten and will more than likely get, and besides it helps keep the site open. Not to mention the cool decal you get. Haven't gotten it yet can hardly wait.

Sunk · Mar 19, 2008

I've been here for a while, and was here before the forum switch too. I paid for the Premium membership, and got the sticker, but haven't seen or heard anything else to do with that.... oh well, at least I got a cool sticker. And I'm sure the majority of what I know comes from hangin out here.

pillen140 · Mar 19, 2008

i know the inertia switch allways pops in explorers, it should be the same thing, just make sure its pushed down.

Sunk · Mar 20, 2008

I made a jumper for the inertia switch, turned the key on, and still nothing.....

Jorley · Mar 20, 2008

Did you happen to check for power at the inertia switch?

No power at fuel pump

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