When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.
Hello, I have a 1977 F-150 with a 460. It has dual tanks and a mechanical fuel pump. I also am running a Holley fuel pressure regulator, The truck runs great with a full fuel stream (clear filter) until I drive about 40 miles. It then has less than a full filter (even though the pressure is about 6 psi sometimes) I have cleaned all the hard lines. Replaced the rear tank, new rubber fuel lines,changed fuel pumps several times (Napa, Oreilly's and Summit ) yet the problem continues. I suspect that the diaphragm in these fuel pumps is expanding and bypassing when it gets hot.
I am thinking of a possible electric pump conversion; but, I should not have to do it in reality. I have considered insulating the fuel pump with some suitable material.
I have a 76 F-100 with the original fuel pump on the 300 6 and it never has a problem. Are all these new pumps just junk. I am interested to see what other people are experiencing.
Thank you in advance.
Last edited by Telestar; Mar 18, 2026 at 05:32 PM.
From what I hear on FTE street/parts talk is YES most reman/repop/replacement mech fuel pumps are junk. Question what carb are you using? Question #2 why are you running a pressure regulator? Is it because you using a Holley or Edelbrock carb?
As I understand it the clear plastic style fuel filter will NOT stay full all the time.
Telestar, when you get 40 miles out are you just looking at the clear filter for an issue or is the truck actually running out of fuel? If it's running right, all is OK. Metal filters don't stay full all the time either, you just can't see inside them to worry about it. Unless the outlet is at the highest point, some air is apt to get trapped above the outlet in them all. Clear filters just let you see the crap that was filtered out of the fuel. If it bothers you, tape the filter over so you can't see in it.
I use mechanical pump, it pumps a steady 7 psi, through a filter and I have a Holley FPR set at 6.5 psi feeding a Holley carburetor. .
Last edited by tbear853; Mar 18, 2026 at 12:08 AM.
Sticking needles in your Holley is my guess (run the steel alky needles) they don't stick
Find a NOS Airtex fuel pump is what I did for my 429, Ebay is your friend for NOS parts
Your fuel pump is good if the pressure is there
* Take the line off the carb and verify you can blow through the needle and seat next time it dies
Pictures of your engine showing the carb and fuel line routing would help us. Are you running a carb spacer? EGR? Does the gas tank have evap port? is your gas cap vented, do you hear a rush when you open the cap?
If it is vapor locking next time you fill you tank add one gallon of diesel fuel to it.
One gallon wont damage anything but it will raise the boiling point of gasoline enough to stop the vapor locking.
Hello, and thanks for your input. I was running an Edelbrock 1406 but just bought a new Holley Brawler 600. The fuel pressure regulator was per recommendation from numerous experts.
No, it's starving for fuel; then I pull over. It has low fuel pressure like 2-3 psi and lot's of bubbling in the filter when it's running badly. I can generally wait for it to cool down (all the way down) and then it starts and runs fine.
Rezvani's Latest Post-Apocalyptic Monster Is a Ford F-150 Raptor Underneath
Slideshow: Called the Fortress, the 850-horsepower pickup combines Raptor underpinnings with military-inspired features, survival equipment, and a starting price of $285,000.
