Fuel pump issues?

Note: Electric fuel pump
Fuel pump is a year old

After my last fill up(both tanks) I noticed my fuel gauge never moved after a full day of driving. I switched tanks and the other tank was half full after I had just filled both tanks and this hasn't changed. I've used one tank so far For two full tanks of fuel.
Also starting the truck after sitting for a half a day or so is rough. It barely fires then is rough(pretty bad) for five seconds or so before it idles great.

Wiring of the system or the pump?

Sounds like a senderissue ora switching valve. I cant remember, one hasa check valve in it that keeps the other tank from filling. In gassers its in the fuel pumps in the tanks, cant remember where its at on the diesels off hand.

The tank selector valve selects both supply and returns to the tanks. There is no check valve. The selector valve may not be shifting on either the tank valve side or the tank indication switching.

This morning truck took a few tries to start then fired up and sounded like a miss fire for a few seconds then the truck smooths over. Then when driving at low Roma the motor would shake like a miss fire(750-900) RPM's until I punched the throttle and the truck has since smoothed over

7.3's will idle with basically no fuel pressure. My selector valve failed between positions, and left me scratching my head for a while. This was with e fuel. It would idle fine, but as you drove, it would bog down, and eventually die.

ghohouston said:

7.3's will idle with basically no fuel pressure. My selector valve failed between positions, and left me scratching my head for a while. This was with e fuel. It would idle fine, but as you drove, it would bog down, and eventually die.

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Not trying to thread steal
but is there a way to manually shift that motor on the selector valve because i think mine is failed in between. Ive replace the fuel pump and both filters my obs has e fuel and my fuel pressure keeps dropping especially in a hot tune i can zero out the pressure if i want but itll maintain pressure at idle

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Filled up the rear tank that the front tank was pulling Fuel from and am now running on that tank. Truck starts great and doesn't seem to have any issues. So drop the tanks and replace the senders? I'm sure the fuel tanks need cleaning or flushing. 250 thousand plus miles

Try taking the return line off up near the fuel bowl and blow compressed air through until you hear bubbles in the tank. Try it with the selector valve on both the front and rear. You may have a plugged line or selector valve.
I'd be booking up a fuel pressure gauge or atleast use a tire pressure gauge on the shrader valve on the fuel bowl when the truck is ideling. Be careful though! lol it's easy to get fuel all over you if you use a tire gauge.
Good luck


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