Disappearing Fuel

NO !!!!!!! DO NOT plug your vent(BR[] is right, instant vacuum, it`ll suck your diaphragm and check valves right out of your pump, if it hasn`t already from having a restriction.

Tell your people at your work, to stick to there jobs. You don`t need check valves. You need to isolate your problem. One of your descriptions led me to believe you already have a restricted vent line. And another description suggests another problem.

Hell, and here I promised myself not to get involved

Put it all back together with 5 gallons of gas. dumped a little gas down carb and it fired for about 3 sec. unhooked fuel line before fuel pump hooked up a 20oz bottle of gas, turned it over and fired up in about 4-5 sec and two pumps of gas pedal. reconnected fuel line and clamped all down turned ignition on and fired up for about 15-20 seconds then died cause of fuel starvation. cranked and cranked all it did was sputter a lot even when I pumped gas but never refired. now it has to cool down cause starter and battery cable are really hot.

I was in the garage this morning looking for something to do, decided to take a fuel pump off of one of the 425`s. I knew the last engine I removed from the car had a decent pump since it ran the engine fine. Pulled the pump, clamped it in the vise, hooked a vacc. gauge to the suction side, three pumps to get 15hg, removed the gauge and plugged it in the discharge side, 3 pumps to get 5lb., at 5lb I heard the return open up and the pump effort was noticeably decreased. So, with the crank, cam ratio you only need to turn the engine 6 revolutions. During the 3rd. stroke on the supply side of the pump as the gauge was approaching 15hg. I noticed the rubber hose I was using starting to egg shape, and the effort needed to stroke the pump noticeably increase.

Got a vacc. guage. At the fuel pump inlet I got 15 and it would spike up to 20 then down to 15 and back up to 20. as soon as I stopped cranking pressure went to 0 zero. Moved on and reattached all lines and clamps at fuel pump. unclamped hose from sending unit clamped vacc line to fuel line and cranked engine over needle moved but not enough to warrant even a one pound gain. Tried this one several times.

I posted the same issue a while back, so I am curious how this will end. My car gets harder and harder to start the longer it sits. Start it everyday, and it starts and runs perfect. Let it sit 4-5 days, it starts, then sputters out and I need to pump more gas to keep it running. Let it sit 2 weeks, and it will crank and crank and crank without starting unitl fuel finally gets it going. Carb bowls always remain full. Choke works properly, and no signs of leaks.

what do you recommend all new hard line or just replace the flex fuel line hose with new?

Try RamZ's plan, but put a new piece of hose on the sending unit end of the hard line. Just like brake hose, the rubber can collapse internally and choke the flow. I dont see the hard line as the problem, but you can blow throught it with an air hose and then plug one of the rubber hose ends with a bolt & hose clamp and pressureize it to check for leaks. It could have worn where it passes up over or through the frame.

Z and BR[] X`s two.

If I could just add one more thing.As BR[] said, replace your hose for the test, any hose from the sending unit end of the hardline to the gas can, will do for your test, as long as you don`t use ANY of the hose that`s on there now. Now for my additional 2cents. When tests are over, and your ready to replace your hose from sender to hard line, and pump to hardline, do yourself a huge favor and use the correct line, correct clamp(s) This stuff is a little pricey (last 25` spool was around $100.00 for 1/4") I think 3/8" is a little north of $5.00 per ft. but you`ll never have to look at it again. The clamp pictured is the style I use, you can go for re-usable style, but NEVER use those cheap ass worm gear clamps. With the crap corn gas we all buy today this is a must. And NEVER run more than 1 foot of hose for suction. Return or vent no problem. Un-lined neoprene gas line is not allowed in my garage, ever!

One more thing, great attitude, "hell or high water" Love it !

No barbed fittings with this type hose( your using for suction so no need to get in to 1/2 double flares) Warm end of hose with hair dryer or CAREFULLY with heat gun before slipping on hard line and clamp immediately. I`ll post a pic of nipple needed rather than barbed for fuel pump/

Goodyear J30R9

I plan on running all new hard line also. I have bent and spliced together 4' pieces with rubber fuel line hose but never bent entire coil in one run, this may turn out to be a nightmare. Any tips or should I stick to the 4' pieces connected with rubber fuel line(The half ass way I know). I will do as BR[] said and plug one side and test for a leak first only to reassure my self I need to replace the entire line, and I'm no artist so I'm not too worried about looks underneath car.