Early Ford V-8 Club Forum

EFV-8 Club Forum / General Ford Discussion / fuel pump vacumn

Reply to Discussion | New Discussion << previous || next >>

Posted By Discussion Topic: fuel pump vacumn -- page: 1 2     jimmyt43 09-30-2010 @ 11:23 AM reply profile send p.m. Member Posts: 17 Joined: Sep 2010 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 reply profile send p.m. Senior Posts: 1961 Joined: Oct 2009 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 reply profile send p.m. Member Posts: 81 Joined: Oct 2009 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 reply profile send p.m. Senior Posts: 6819 Joined: Oct 2009 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 reply profile send p.m. Member Posts: 17 Joined: Sep 2010 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 reply profile send p.m. Senior Posts: 1961 Joined: Oct 2009 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 reply profile send p.m. Member Posts: 17 Joined: Sep 2010 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 reply profile send p.m. Senior Posts: 6819 Joined: Oct 2009 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 reply profile send p.m. Senior Posts: 7253 Joined: Oct 2009 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 reply profile send p.m. Member Posts: 17 Joined: Sep 2010 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.

<< previous || next >>

PAGE: 1 2

NOTE: YOU MUST BE A REGISTERED USER AND BE LOGGED IN TO POST (and reply to) messages in this forum. If you are a first time user, please click the CREATE A NEW ACCOUNT in the masthead above to register and Log In. After that, all you do is LOG IN to enjoy using this site.

DISCLAIMER: The V-8 Club does no independent testing of any of the opinions, thoughts or suggestions presented in the website on the Forum, in the Tech Tips section, or any section. A reader should consider the website to be a forum wherein differing solutions to a particular set of circumstances may be discussed. Ultimately, the selection of an item for an individual's vehicle must be based upon the independent study of the vehicle owner in consultation with people in the hobby and restoration experts.

EFV-8 Club Forum Home | Back to Home Page | Contact the Webmaster

Copyright © 2009 - EFV-8.org
Powered by < CF FORUM > v.2.1