Topic: fuel pump vacumn

jimmyt43	-- 09-30-2010 @ 11:23 AM
	Hi i have a 49 tudor with a flathead v8, when i start the vehicle cold it will start and have vacumn produced by the fuel pump. After it warms up and i shut her down and then go to restart i have no vacumn being produced by the fuel pump and no fuel to the carb. If i let it sit and totally cool of (several hours or the next day) it will start up and the fuel pump produces vacumn until i shut it down and then no vacumn again. If i remove the fuel pump and actuate the arm manually the fuel pump works, so its not the pump. any ideas out there. This message was edited by jimmyt43 on 9-30-10 @ 9:03 PM
37RAGTOPMAN	-- 09-30-2010 @ 12:49 PM
	does it die out when warm, like starving for fuel? or does it keep running, if it dies out. remove the pump when it is happening and see if the fuel pump push rod is hangine up,like binding in the bushing ? is it clean, or rusty.maybe from sitting got rusty, from condensation, let hear how you made out,37 RAGTOPMAN an KEEP on FORDIN,,,,!!!!!!
Pauls39	-- 09-30-2010 @ 1:58 PM
	Check the vacuum line from the intake to the fuel pump. This line may be gummed up and closing when it warms up. Also check the vacuum ports. The pump should only provide vacuum when the intake vacuum drops (acceleration or heavy loads).
supereal	-- 09-30-2010 @ 2:46 PM
	Are you sure the pump diaphragms are fuel-proof? Alcohol in the gas will soften them so they can't produce vacuum or pump fuel. The valves in the pump are also affected. They get sticky and adhere to the seat. The effect is more pronounced when the pump is heated. When allowed to cool, the parts stiffen and work for a while.
jimmyt43	-- 10-01-2010 @ 9:34 PM
	ok so i can remove the fuel pump and manually activate the fuel pump arm and draw fuel out of a container and pump it into the carb bowl, i then reinstall the fuel pump and run it off the pushrod it will not draw fuel from the tank, the tank is clean and the line free of obstructions. I have checked the pushrod length from the intake to its lowest point and the highest point which is 2 1/4" and 2 1/2". I then checked from the fuel pump base to the fuel pump arm at its lowest and highest points which were 2 1/4" and 2 1/2". This tells me the pushrod travel should be correct. I am stumped!
37RAGTOPMAN	-- 10-02-2010 @ 5:15 AM
	jimmy43 is the push rod the correct one, if it iS too short it will not move the arm, when you move the arm by hand it pumps, and it travels the full distance but maybe the rod is the wrong one? put the rod at it highest point and then install the pump over the push rod do you fee a resistence, like the diaphram is collasping,and the pumP seems to be starting to pump fuel? let hear how you made out.37RAGTOPMAN an KEEP on TRUCKIN...!!! NICE 49
jimmyt43	-- 10-02-2010 @ 8:01 AM
	The pushrod spec is 10 1/16" and mine measures out at 10 1/16". I also measured it with a caliper mic and it was like 10.076. I tried putting a 5/32 nut which is about a 1/16" in the arm hole to make the length longer and that did not help.
supereal	-- 10-02-2010 @ 8:39 AM
	It is possible that your gas cap isn't properly vented. Sometimes we find a radiator cap there. If the fuel pump works sometimes, but not others, that can be the cause if the pump is "fuel proof" and the diaphragm isn't flopping. Otherwise, I'd take a close look at the pump arm. We have seen many of them that have loose or otherwise poor linkage.
TomO	-- 10-02-2010 @ 9:29 AM
	There are a couple of possible answers to your problem 1) worn operating arm pivot, the pump will operate by hand but not very well when on the engine. 2) dirt in the valves allowing the vacuum to leak down when operated by the starter. 3) bowl gasket leaking, causing the pump to suck air. 4) flex line or tank line leaking air causing the pump to suck air. You can hook up your vacuum gauge to the flex line input and crank the engine. The pump should produce 10 inches of vacuum in 18 seconds of cranking and take at least 1 minute to reach 0 after stopping cranking. If you do not reach 10 inches, look for a leak in the flex line or the bowl gasket. Worn pivot in the pump arm can also cause this. If you reach 10 inches but it leaks down fast or in a non-linear way, the fuel pump valve is bad. Tom
jimmyt43	-- 10-03-2010 @ 12:26 PM
	no vacumn at the flexline...removed the fuel pump and checked the arm, the piece of metal that holds the pushrod in place has moved to a position that will not hold the pushrod against the arm. This fuel pump is only 2 weeks old so I have another one coming on Monday.
TomO	-- 10-04-2010 @ 9:01 AM
	It sounds like you have one of the Airtex pumps. The Offenhauser pump sold by Speedway is of better construction. Tom
jimmyt43	-- 10-05-2010 @ 1:16 PM
	put the new pump in and have good vacumn and flow of fuel, then the flow went away. went to remove the fuel line from the flex line to the tank and look what I found behind the left front inner fender wall when I took it out (see attached).
TomO	-- 10-05-2010 @ 1:43 PM
	You might have a vacuum leak with that line. It looks like there was a problem and the fix was to add a short length of line to the rotten gas line. Here is a site that has the 5/16" line that you need. http://www.quantaproducts.com/prodinfo.asp?number=FLGGL5001 C&G sells the 1/4" copper coated line for less money. Tom
supereal	-- 10-05-2010 @ 3:09 PM
	For years we didn't see bad gas lines. Now, they are becoming common. Apparently, the "oxygenated" fuels are accelerating rust and corrosion. Simply replacing the line now is a good idea. For about $20, it will prevent being stranded.
39 Ken	-- 10-06-2010 @ 4:52 AM
	Your first stop should be at Roy Nacewicz web site; http://www.fordscript.com/ . He sells fuel lines, among many other parts for our cars, as originally made for Ford and they are exact dupilcates. Roy deserves our business as he has been a constant supporter of our hobby and our club. Give him a try. Ken

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