Topic: Fuel pump


39FORDPU    -- 06-18-2022 @ 6:23 AM
  I recently purchased a 1939 ford, it starts good, idles good, but when I drive down the road it seems to surge, sometimes it feels like it's going to die, could it be the fuel pump? Thank you for any input.


carcrazy    -- 06-18-2022 @ 11:39 AM
  Check for any vacuum leaks at the carburetor and/or intake manifold. Remove the hose to the windshield wiper and plug the tube on the manifold to eliminate the wiper motor from the system. How much vacuum does the engine have at idle? Be sure to check the fuel level in the carburetor and set it to the proper level. The float in the carburetor may have developed a leak allowing it to sink. Also check the power valve in the carburetor to make sure the diaphragm has not ruptured and that it holds a vacuum. After these carburetor checks have been made and you have corrected any problems, remove the fuel line at the carburetor and direct it into a can while cranking the engine with the starter to determine if the pump is providing an adequate amount of fuel.



37RAGTOPMAN    -- 06-19-2022 @ 9:39 AM
  FUEL PUMP
I would try removing the air cleaner and take if for a ride,
does it run any different, the aircleaner may be dirty, it should cause a rich running, with smoke out the tailpipe
do a fuel pump pressure test as well as a fuel pump output, test like carcrazy said,
how is the fuel line from the rear gas tank,does it have a inline fuel filter ? it might need replacing,
also the fuel pump has a filter screen inside the top cover, remove it and check for a clog,

I would remove the 2 plugs on the front of the cabruretor, use a paper towel to pick up what come out and is if there is any dirt,
hope this helps 37Ragtopman


TomO    -- 06-19-2022 @ 9:52 AM
  The fuel delivery system gets blamed for quite a few ignition problems. Here is what I would do to diagnose the problem:

Read and perform the tests in this post:

https://www.earlyfordv8.org/forum/viewmessages.cfm?Forum=14&Topic=15460&keywords=fuel%20delivery

Tom


39FORDPU    -- 06-27-2022 @ 3:50 PM
  I bought the car in October and it was delivered in November, I didn't get to drive it until this spring ( wisc), over the winter I bought a locking gas cap from a known vendor and it didn't fit so I modified it and put it on, I checked it after someone said to, it was tight so I put the old one back on and the car runs great.


ford38v8    -- 06-27-2022 @ 6:20 PM
  You can use your new cap if you modify it further to include a vent.

Alan


wmsteed    -- 06-30-2022 @ 9:59 AM
  I am a little late in my reply to 39pickups question which has been answered to great length. Having purchased many vintage vehicles throughout the years, I will offer my suggestion (s) to the problem of why a vehicle can run poorly without doing a major overhaul to the vehicle.
The first thing I do to a newly purchased used vehicle is check it over very carefully before i attempt to drive it.
Naturally fluids are at the top of the list, then hoses, radiator cap, is it pressure, how much, wires, especially battery cables for clean tight connections, tires. pressure/condition.
On many occasions I have found that the fuel cap on the tank filler is an un-vented cap and the primary ignition wire is hooked to the wrong side of the ballast resister. A weak coil can act like a fuel problem.
Several years ago I stopped in a roadside rest in Idaho, shortly after stopping a '55 Chevy pickup pulled in, a young lady got out of the pickup, walked over to me and asked if there was a phone available, she went on to state that her trucks was acting up, she wanted to call her father to come get her.
I offered my cell phone, then asked what the problem was, the lady stated the engine was running very rough, almost to the point of quitting. I offered to look thing over.
Upon lifting the hood i saw a brand new shinny engine with an HEI ignition. I noted a stock '55 GM ballast resister on the firewall with the HEI hooked to it. I explained to the young lady, who I should mention was dressed in a mechanics uniform from a local Chevy Dealership. I removed the wire from the HEI, placing it with the 12v terminal. i next noticed a nice shinny fuel cap, removed it an noted that it was UN-VENTED.. I got an aluminum can from the trash, cut it open and placed it over the fuel neck.
I then explained to the young lady that she had two problems, the power source from the ballast resister was not supplying 12v to the HEI and the unvented fuel cap was creating a vacuum in the tank that the fuel pump could not pull through.
The young lady told me she was a ASE Certified Mechanic, and that I had just made her feel very stupid, and that none of the other mechanics she worked with had caught the problems I found..
My response, I'm Old School, pre computer, in my world we don't plug in a computer and wait for it to tell us how to fix something. I can still hear my auto mechanics teacher telling us.. Intake, Compression, Power, Exhaust, the basics of the internal combustion engine

Bill
36 5 win delx cpe


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