some trucks bleed air better than others?

[6.9poweredscout]

I've noticed if I run my truck low on fuel and it picks up air (gauge is off...I cut it too close sometimes) its a pain to restart even with an electric pump. Yet I've run other trucks I've owned out and just a few seconds cranking lights right off. I it cranks fast, and I'll bleed injectors and filter, but sometimes I'll have to give it a sniff of crack for it to catch. Any ideas, or some are just stubborn?

 

[chris142]

Mine starts easy. I even have an extra spin on water filter in line. Ill run out of fuel,pull over,switch tanks,turn key,rrrrrrrr,rrrrrrrr about 20 seconds total and it will fire up. Runs rough for a few seconds then smoothes out. No electric fuel pump either.

 

[icanfixall]

My truck will prime hard. then the next filter change it primes easy. I have wondered why for years. nothing seems to change nor can I predict when it will prime hard or easy. What I have noticed is when I turn up or down the fuel. Sometimes I start right up. No stumble either even after loosing the fuel from the pump when the side cover comes off. A note about that fuel. I place a sandwich bag filled with paper towels under that area to catch the fuel draining out. I don't care for the fuel bath the valley pan and the starter takes when its allowed to drain to the ground... Anyway, If I don't have to hand crank the engine more than maybe a 1/2 turn the engine fires up fine. but if I miss the allen wrench when I hand crank the engine nd have to turn it more than 360 degrees I will have a tuff time restarting. I think this is because of air being pulled into the injection pump with the side cover off.

 

[junk]

My 89 was always easy to restart when run out of fuel. No clue why. My 93 i've thought's been Ok also after doing fuel work, swapping engines etc. I'm mechanical lift pumps on both.

 

[6.9poweredscout]

Think I figured out my issue. I "ran out" with a 3/4 full tank today. I drifted into the gas station and when I went to remove the cap there was a good long hiss.... after the fast fill mod there's no way to vent the tank as the fuel pulls and the faucet pump can't pull through the vacuum. is there a vented cap available? or maybe just drill a small hole in the filler neck right below the cap?

 

[FarmerFrank]

I welded a nipple to my filler necks and ran a hose up in the bed side for better venting

 

[OLDBULL8]

I never run out of fuel when there is still 3/4 tank. There is a vent hose with a rollover check valve on top of any fuel tank. Ya just gotta clean them, mud, insects etc.

 

[6.9poweredscout]

I have a fitting in the top of the tank to a fitting in the filler neck, when the cap is on it's a closed system.

 

[OLDBULL8]

I have a fitting in the top of the tank to a fitting in the filler neck, when the cap is on it's a closed system.

That's fine only if you have a venting gas cap, otherwise it creates a vacuum in the tank. The only vacuum needed is at the place doing the sucking. ie: Lift pump.

 

[6.9poweredscout]

Yessir, found that the hard way. Did Ford use any venting caps that'll work I'm my filler neck?

 

[junk]

I thought the true diesel caps ford gave with the trucks were vented. Could easily be wrong though.

 

[6.9poweredscout]

Very possible, I think I yanked this one off something at the u pull it because it had the lanyard.

 

[79jasper]

Somewhere I have the caps from my 94.
Only took them off to put on locking caps.


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[icanfixall]

I always hear the hissing of air when I open my tanks to refill them. I harpooned my tanks and now the rollover valve area has a 1/2 inch hose running to the fill neck just under the cap. I someday will install a 1/4 inch nipple and run a vent hose loop. I do believe the caps that came stuck have a vent in them but they are not whats called a vented cap. I don't know what vacuum they will hold but the sound is always the same when I open the tanks. I guess its like a pressure cap on our radiators. they hold only so much pressure than they release it. the caps holds only so much vacuum in inches or mercury. then it wont hold any more.