empty fuel filter

the problem is that the truck will run for a time then the fuel filter runs dry and it stalls. it needs to sit for a few mins (up to 20) before it will start again.  Been working on this a while, after reading some posts this is where we stand. New fuel tank, filler hoses, pickup filter, rubber fuel lines replaced, vent hose on top of tank replaced, electric fuel pump installed (Napa 5.5-9 psi 35gph) bypassed the mech, new fuel filter. Did bypass/ pressure check on metal fuel lines so i believe them to be leak free. It is making me crazy. Hopefully I missed something easy and you guys will point it out to me. Thanks in advance for all you comments and the forum.

Hi elbutch.., welcome...! 

WOW..!  That is a tough one.  All I can do is ask a few questions.

When doing the pick-up filter, were you sure the pick-up tube itself was clear..?

Assuming the "vent hose" you speak of goes up to the gas cap area..?

If so., do you have a "vented" gas cap..?

---------- With an un-vented, tightly sealed tank, the pump can pull a vacuum on the tank

that will over power the pump.

thanks for the help. blew out the p/u tube. the vent hose i believe is the for the eec. I did replace the orig gas cap with a locking cap. I have tried driving with the cap off and that had no effect, so believe vacuum lock not to be an issue. a little longer part of the story: I have been battling this for 12 mos or so. started with replacing the fuel pump. ordered the recommended one and found it had the wrong size intake tube. switched hoses to match 5/16. delt with the getting stuck issues while trouble shooting. Thanks to the Forum for info. with help from Auto Zone guy found a pump with the right size intake 3/8.

Airtex actually has the wrong info and part numbers on the pumps. this drove me nuts for a while. the prev owner said there was fuel delivery issues so his mechanic added an elec fuel pump to assist. turns out it was too weak and 5/16 also. Hence replaced it ALL.

Sorry to expand the story, But it kinda feels good to vent. I am starting to think it is a carb issue and may need to do a rebuild. I just cant figure out why and its making me crazy.

I did see in a post mentioned where a exhaust leak was hitting the fuel line and causing issues. so i will crawl under and start poking around.

on another note; how do you get your description under your post. ie --Jeep recovery unit---?

That was my next guess.., the carb needle/seat & float. Least likely but not impossible.

Is your filter clear/glass...? Meaning how did you know it was empty.

My filters are clear &/or glass & vary fr. time to time. Sometimes full, sometimes empty.

That's because they're laying horizontal, not vertical. (the air bubbles never get out)

BTW.., by-passing the mech. pump.., I assume there are no fuel lines still hooked to it.

AND, you can't be to wordy when asking/searching out an issue. The more info./history

the better.

Click on your name (upper right on home page) Click on "my settings" then click on

"signature"  ------ It can be updated at any time.

the area under each post is your siggnature accessed by way of clicking on your name

Forgot..,

An exhaust leak but more commonly just the heat fr. the ex. pipes can heat a (too close) fuel line &

create a vapor lock.

got the signature, thanks.

TG, I have a clear plastic filter, horiz also. had no trouble with it for 2 years so i stuck with it. although after more reading i will switch to a glass one. then this issue started and i started replacing stuff.  when its running the filter will eventually get full and there is good pressure on the gauge. as for the floats and needle/ seats. i had the carb off, pulled the bowls, set float height, new power valve and gaskets. cleaned and inspected the needles and seats. they looked god to me. weren't sticking so figure they are okay. However, with all i have done the carb is the only/ probable issue. may just get the rebuild kit and have at it.

oh, and the mech  fuel pump is still there. i have the lines sealed off. i havent found a plate to cover the levers hole. also, the stone filter in the carb body is clean as well.

It is quite the delema

Not a big fan of elect. fuel pumps.

W/O a cut-off (inerta) switch.., they don't shut off in a crunch or rollover. Great as a backup however.

In aircraft.., we had them parallel to the mech. pump. They were used on takeoff & landing only.

Clear plastic filters are OK. The glass ones are rebuildable is the main difference.

"good pressure on the gauge" 

Didn't know this...,   Is this a dash gage or a test unit..?

If this reading remains steady.., you may have an ignition issue.., not fuel.

pressure gauge is the inline type mounted on the fuel feed line. just to clarify, the gauge  dances the jig till the filter is full then pressure will hold steady. I was thinking of installing a better mech fuel pump, holley or some such type with a higher than stock pressure. was going to keep the elec pump online to help it. what are your thoughts on this? unnecessary/ overkill?

and its been raining here for 2 days which drags this out, as i am a garageless 'shade tree mechanic'.

thanks again for your input.

 We're, pretty much, all "shade-tree mechanics" here... >< <'>

Ya.., backing up a mech. pump with elect. is overkill.

The airplanes have check-valves to keep the pumps from back-flowing thru each other.

Point being, while on short final approach, a failed mech. pump wouldn't even be

noticed as the elect. is taking over. (switch on of course)

--- a bit more important in an aircraft ---

Your Holley has a min.- max. rating as to pressure.  Most stock mech. pumps are in that range.

A "quality" mech. pump can't hurt a thing.   www.summitracing.com

Too much press. can cause problems as well.

Keep in mind the fuel isn't hauling ass thru the lines. Even at high speed.., it's still just a slow flow.

If your filter fills then empties at rest.., there could be a problem in the pump(s) in that

they're allowing fuel to flow back to the tank.

Check me on that but I think the line above the pump should hold pressure.

Just adding my $.02, I had the same problem with a fule filter draining when the truck was left setting.  It turned out to be a small hole eaten into the top of the rubber fuel line near the tank by a mouse.  He must have gotten a mouth full and quit.  It took a while to find it because it was on top of the hose where I couldn't see it.

Not saying  a mouse got yours, but you may have a tiny air leak in the line.  If so, it would most likely be before the fuel pump and not big enough to cause leaknig of gas but big enough to allow air to leak into the line when setting idle.  Air will travel to the highest point, in this case the filter.

The other possibility that has already been mentioned by BB is the seat of the carb float valve.  However, that would probably cause over filling of the float tank when running and flooding the engine or very poor running characteristics.

Good luck,

>-

http://www.supermotors.net/registry/media/672876

http://www.supermotors.net/registry/media/672878

What the filter should look like if everything was normal.

Thanks for the thoughts gentlemen. as mentioned about the floats. i believe youre correct. that it would not have any effect on the fuel level in the line/filter. so i am going back and re-check all the hard lines and connections with a brake bleeder and see what pressure levels i get. Thanks Seabronc for the pics, now i feel bad at how dirty my engine compartment is /emoticons/[email protected] 2x" width="20" height="20" />

BB, could you elaborate on your $30 homemade HEI elec ignition? it sounds very interesting.

DO keep us posted.., we want this solved as well..!!

Check me but I think you already have an electronic ignition (Ford Duraspark)

       ---- This HEI wouldn't do anything different for your rig -----

It's simply the 4 pin "domino" sized unit that sits inside most older GM dizzys.

It's attached to a heat sink & wired up to the Duraspark dizzy I got off an '83 Ford eng.

My rig ran good & smooth but when I did this mod.., (I had points B/4)  it was better yet..!!

Funny though.., I entered that info. many years ago & you're the first to notice/call attention to it... :-B

If you need more info, I'll dig up the web site & send it to you. 

It looks like spaghetti 'cause I added a 30amp relay (left) & a junction block (right) for wiring.

For this thread though.., we should stay "on topic" ---- Your truck & it's issues.. >< <'>

OOHhhhh, so the ign part was to switch over from points to electric. thats pretty cool. thanks for the offer, but NO. electronics of any sort is my short comming. I will post the solution, should i find one.  i am now being setback by a blown oil pan gasket, as i discovered oil everywhere when i crawled under to check for leaks. every time i touch something, something else breaks.... its always something. Damn Gremlins!!! lol

Yep.., welcome to "grease-monkey 101"

A year from now you'll be an expert & helping others on this board... /

UPDATE: Ahhh the Gremlins have been having their way with me. so after replacing the oil pan gasket, which was a breeze. There was still oil leaking, finally tracked that down to the mech fuel pump. the body housing became loose and would drip when the motor was under strain. This dripped back onto the gasket near the bolts that i thought were leaking.Grrrrrr Lengthy and Proper diagnosis would have saved me some hassles. Go Figure, patience-virtue-whatev.

As for the fuel issue. I have temporarily ran rubber fuel line from tank to pump to carb. It runs like a champ with no problems as yet. BUT, the filter still runs empty from time to time. i can drive 30 mins to work and the filter is full or get there and its empty (but the truck still runs)  so i will keep an eye on it until i figure it out.

Now to clean it up and sell it .HaHa. I have an offer to move to St Thomas. I think the Bronco would be overkill down there /emoticons/[email protected] 2x" width="20" height="20" />

thanks for all the input

Good work..!!

Thanks for the update..!  That's really rare these days.