8ba fuel pump rod getting stuck

B

bill41ford

Member
Started my newly rebuilt 49 8ba , had a couple small issues but I have a fuel pressure gauge on the fuel block and on the initial start up I had fuel pressure showing on the gauge, after running for a few minutes the motor stopped - I tried to start it and saw there was no movement on the fuel pressure gauge . Unbolted fuel pump from stand and watched the rod - it moves up and down, I rebuilt the fuel pump and I operated the pump linkage and it seemed ok - put all back together (didn't change anything) Started motor, ran for a few minutes and fuel pressure was ok on start and then went to 0 and shortly after the motor stopped. This time I took the screws out of the top of the pump and found the diaphram was pulled down like the rod was up - turned the motor over and there was no movement of the diaphram, started to loosen the fuel pump from the stand and when the bolts got loose the diaphram popped up - put it back together and it ran for short time and did the same thing. Any ideas? I have an old Edmunds dual carb manifold and I put a 10" rod in - seems to go into fuel pump cup on linkage and works for a short time ...
 
Yes a new bushing was installed and movement of rod felt ok , new development, left it sit overnight - there was no fuel pressure guage movement when I left it - after sitting overnight I turned it over and fuel pressure looked normal for a few minutes until motor heated up some, then fuel pressure dropped to zero again. I am going to let the motor cool and try it to see if it recovers again for a while - had an idea that maybe fuel pump linkage was hanging up after a short time, but will wait for a cool down to see what happens
 
Take the fuel pump apart again and double check the diafraghm for tiny cracks.
It probably is a fuel pump problem. Do you have a spare fuel pump you could install to see if there is any improvement?
 
bill41ford said:
The fuel pump is just rebuilt - but I am taking it apart again to try to figure something out.
Click to expand...
Make sure the diafragm screws are tight and that it's not sucking air.

Double check the length of your fuel pump pushrod. 1949-53 Ford fuel pump push rods are 10 1/16 in. long.

Is your gas tank/ cap vented? Remove your gas cap and see if that helps.
 
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Fuel pump rod is correct length - running from a small gas tank and tried without cap on - Iwas going to take things apart to check inside fuel pump stand but after letting things sit overnight I turned over motor and fuel pressure was back and engine started - kept it running for a few minutes ( about 500 to 1000 rpm, also having an idling issue, with idle screw bottomed out it does not touch throttle stop, engine idles down to about 500 on tach but throttle stop does not touch linkage) about the time the motor shows some temperature on both temp guages the fuel pressure went to 0 again. This has happened 2 times now, letting engine sit overnight and fuel pressure is back until engine runs to show some temperature, this all has to mean something , Trying to decide if temp has something to do with all of this - also wondering if timing could be an issue - I want to check running timing but without being able to idle I would need 5 hands and pretty quick with timing light - timing was only roughly statically checked - when fuel pressure is present engine starts pretty good, so I have to think timing has to be close.
 
Does your car have the flexible cloth covered OEM rubber line near the firewall that feeds gas to the carb? If it does, remove it to make sure the inside of that hose has not deteriorated as a result of today's ethanol gas. The hose looks something like this one.
https://www.ebay.com/itm/2815256774...044&customid=2643d5c1407718128418b1bc277995d2

QUESTIONS:
Also, when you say "also having an idling issue, with idle screw bottomed out it does not touch throttle stop, engine idles down to about 500 on tach but throttle stop does not touch linkage)" suggests that it could be a carburetor adjustment issue. The carb idle screw adjustment should first be set properly. What kind of carb are you using? Is your choke electric or mechanical? Have you contacted Charlie Price for his opinion?
 
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I am feeding gas from a small tank for now, don't think float is too high cause problem is fuel pressure drops to 0 - fuel pump bowl is full of gas to the top , bought carbs from Charlie Price of vintage speed and they were run before being sent.
 
Is there the possibility that you are somehow experiencing vapor lock?
Where is the little tank you are using located in relation to the carb?
Is it higher or lower than the carb? If it's sitting on the ground is the pump strong enough to "pump" the gas to the carb?
Is that little tank vented?

How many carburetors are you using?

QUESTIONS:
Also, when you say "also having an idling issue, with idle screw bottomed out it does not touch throttle stop, engine idles down to about 500 on tach but throttle stop does not touch linkage)" suggests that it could be a carburetor adjustment issue. The carb idle screw adjustment should first be set properly.
What kind of carb are you using? Is your choke electric or mechanical?
Have you contacted Charlie Price for his advice?

Is the height of the fuel pump stand on the old Edmund intake you are using the same height as the fuel pump stand of the stock 8BA intake manifold? Measure both and compare.

Be sure your Edmunds intake is meant to fit the 8BA engine?
Did your 8BA engine run good with the stock 8BA intake manifold and 2 barrel carburetor?

Does your intake manifold look like any of the Edmunds shown here:
https://www.ebay.com/sch/i.html?_fr...0.l1313&_nkw=edmunds+intake+manifold&_sacat=0

Or here:
https://www.jalopyjournal.com/forum/threads/8ba-dual-carb-set-up-non-prgressive.1065730/
Notice use of electric fuel pump.

PLEASE post some photos of your entire engine set up. That would be a big help. Include clear photos of your carb and carb linkage set up, intake manifold and your distributor set up.
 
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Appreciate response and questions , I will take some pictures , I have tried the little tank above the engine and below, with and without cap and same results. The Edmunds manifold looks exactly like the first link with carbs and 749.99 price. I have primary / secondary setup with progressive linkage (brand new 97 style carbs,manual choke on primary set up by Charlie Price, as I have said, and I do want to contact him) I have the linkage set right now so I do not actuate the secondary carb, concentrating on 1 carb, secondary throttle plates are closed . I do need to address idle issue. This is a new build and with .30 over / mild cam, cast iron fenton style headers. When I had it apart to check pump and dry fuel bowl, turned over engine and filled bowl until full and then with choke on engine started - ran until able to have choke off and when fuel pressure goes to 0 and engine stops the bowl is still full. I won't have time today to try anything else but really appreciate ideas and will take some pictures as soon as I can, probably not until tomorrow.
 
Have you removed the pressure gauge and fuel block and tried to run the one carb right from the pump ?
 
Got to take the pump top off and found the same situation as the last time, the diaphram does not move when engine is turned over - When I begin to loosen the pump from the stand I feel a pop when bolts start to loosen and then the pump goes up and down as it should when the engine is turned over. I took the stand off and pulled the rod out - it is 10 1/16. checked the fit of the rod in the pump linkage cup and it is a good fit but has isn't tight. The rod has one smooth end and one end that is not smooth - rod came from Van Pelt - I figured the smooth end should go down into the bushing. I can't figure what I am doing wrong when installing pump into stand - I feel the rod with the cup and when I feel the top of the rod push the pump in and onto the rod - I pull slightly out to make sure cup is over top of rod , I double checked that the last time I put it together. Something is not correct inside pump stand when I put it together - I just don't see what I am doing wrong - and when I get it bolted up with the fuel pump top off, I can see the diaphram go up and down when the engine turns over. I have done this 2x now and something goes wrong inside the stand and after running a short time, I lose the pump movement? Of course I can't see inside the stand, but something can't be fitting or operating correctly. Not sure what I can be doing wrong on the pump install.
 
There must be something just very slightly binding...a tiny misalignment or fit. I wonder if the pump stand is not quite flat on the base (many have been filed to fix oil leaking) . Maybe try to see if that's the case if possible, or see if the rod/cup interface can bind at full stroke. The pump stand may have been filed more on one side than the other...or maybe it's a tight spot in the pump itself. It obviously occurs at full pump stroke so that's the place to concentrate on.

The odd stuff really makes these things a head scratcher!



Have you tried a different pump? Never know....




Terry
 
I am in the process of looking at every aspect of the pump / stand / rod , I don't have another pump - definitly binding after running a while, haven't figured out what is yet, but there just aren't that many pieces involve, thanks for all the ideas, I will get past this...
 
Remove fuel pump stand after engine has run and stops for lack of fuel, then turn the engine over and observe if the rod drops .020 of its own weight from its high point. Sounds like a heat problem. Perhaps try a different push rod.
 
Bill OH said:
Remove fuel pump stand after engine has run and stops for lack of fuel, then turn the engine over and observe if the rod drops .020 of its own weight from its high point. Sounds like a heat problem. Perhaps try a different push rod.
Click to expand...


Just to be clear...I'm sure Bill meant .200" of rod travel.



Terry
 
rod does move up and when I have watched it with fuel pump removed - can't tell what is happening inside fuel pump stand when pump stops pumping until I loosen the fuel pump bolts and what ever is binding "pops" back in place and then all is ok again - about ready to cut the back side of the pump stand so I can see what is happening in there - I did not have time yesterday to really check the stand base , etc for trueness - will try to do that today - life keeps getting in the way of tshooting this problem, thanks for all suggestions - will figure this thing out
 
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