IDI out of fuel

tradergem

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I second snicklas's suggestion that your fuel problem may be in the fuel tank selector valve. A couple years ago I was driving my truck and ran out of fuel with a 1/4 tank still showing on my gauge. I switched over to the rear tank and the truck sputtered a little and stopped and I had 3/4 of a tank in the rear. So I figured it was the filter or the mechanical fuel pump. After replacing both it turned out to be the fuel tank selector valve had become clogged with pieces from the broken fuel tank pickup and I couldn't get enough fuel from either tank to make the truck run.

I put in a new selector valve and have had no more fuel problems other than having to keep the front tank above 1/4 full. You could temporally bypass the selector valve and run off one good tank until you put in a new selector valve. That is if it turns out to be the problem.

Bye the way if you end up replacing your selector valve with a universal fit selector valve that has the hose barbs and not the Ford quick connectors you can cut down these fuel line repair tubes that will fit your quick connections and then clamp a short piece of hose on it and the barb fittings on the valve.
 

IDIBRONCO

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Yes your injector pump can keep the engine running even if the lift pump fails. When you bring it back to an idle, then it looses suction. This is why I suggested the lift pump in the first place.
 

adamsanders

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Ok, so moments after my previous post I spun the motor with the outlet of the lift pump still open to air and all of a sudden fuel started pouring out. I reconnected the line up to the filter and depressed the Schrader valve while I cranked and in few seconds fuel came out there too. I began cycling the glowplugs and cranking. I could get it to hit and run for like 5-10 seconds by pedaling it but it stalled every time. On the 5th or so bout of this I revved it pretty high and held it for a few seconds and sure enough it caught itself at 800 RPM or so and idled fine for about 20 minutes. Hopefully this saga is over and thanks to everyone who helped me. I'll update tomorrow if it "holds the prime" and starts back. The lift pump I took out look fairly new and was actually the same pump I had bought to put back in. Hopefully nothing fishy there. Thanks again!
 

IDIBRONCO

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Well I guess you know what direction you need to take now. And yes, it can be "fun" to reprime your fuel system after running out of fuel. I'd say that it actually started up fairly quickly.
 

adamsanders

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Is there any harm in pressurizing the tank with the rag/nozzle trick? I believe I did do this once after reconnecting to the lift pump. I just don't want to risk filling the crank case with diesel from a busted diaphragm. I don't believe this happens because it visually pumped well afterwards but I was just wondering the risk.
 

IDIBRONCO

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I think that there is a risk. I have done it myself, but only while the engine is being cranked over. I tried to keep the air pressure low or at least not in the tank for very long.
 

junk

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If I'm thinking right the fuel pump should have a weep hole on the bottom of it. So if a diaphragm ruptures it should put diesel on the ground out of the weep hole.

I've also pressurized fuel tank with air to get fuel moving.

Glad you got it running. With a decent pump the prime up OK.
 

icanfixall

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Also happy to read you got it running. Now try to remember the not less than 1/4 tank rule and this wont happen again... Plenty of good reading here about how to repair the tank suctions so the last gallon of fuel can be sucked out. Might just purchase 2 of the suction shower heads and install them. They actually rest on the bottom of the tanks so they can really draw down that last drop of fuel.
 

Tony Stottler

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First time 6.9 idi diesel 87' van owner here. Run out of fuel at quarter tank on gauge. Tap anywhere on the bottom of my 1 fuel tank and it sounds completely empty.
Once 10 gallons are in the tank sitting level, why couldn't I remove schraeder at canister filter and use compressed air to force the fuel up to the filter?​
 

IDIBRONCO

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It can work, but be careful. Very much air at all can do some damage. I have done this and only used a 2-3 second burst of air. If you have a way to regulate the air down to very low pressure, you could probably use a constant supply of air. By low pressure, I mean less than 5PSI. The down side to doing this is that it can rupture the diaphragm in your lift pump. It's made to create suction which is basically a vacuum. You will be putting pressure on it instead.
 

Registerrr

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Have you had any luck since replacing theift pump I'm having the exact same issue and tips or tricks I just replace my leaking pump truck was running fine now nothing! Tried filling filter everything
Ok, I replaced the lift pump and reconnected the line back to the tank. I cranked the engine over 2-3 times and I am not getting anything out of the lift pump! I'm fairly certain I put it in under the cam as directed but it's very difficult to see. I listened close and turned the engine over with a momentary button for the first time and i felt a little suction on my finger at the inlet. How do I get fuel up to the pump? Before I reconnected the lines I blew compressed air from the tank and fuel came out at the lift pump end
 

adamsanders

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Hi Registerrr, this a pretty old post from when I first bought my truck. The problem was not the lift pump at all as I recall. My tank selector valve assembly on the frame rail had a hairline crack on the housing and was letting air in. Best thing I ever did for this problem was put a 5-6” run of clear hose from the hard line at the passenger front wheel to the inlet to the lift pump. I could see air bubbles even when running so I just started working backwards from there. I eventually replaced everything, fuel lines, tank, pickup in the tank, injection pump, etc. But this clear line trick really helped me get it going initially. Truck has seen probably 20,000 miles of extremely reliable use since this post so it’s definitely worth taking the time to work on!
 

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