Fuel Pump replacement or upgrade?

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After sitting for about three months I started my car this weekend and immediately noticed an issue with the fuel pump, it's literally pumping fuel like a torn artery. I'm looking at replacements and was hoping someone would have advice on what's my best option. I don't think I had issues with the factory pump, unfortunately the car sits for weeks a time so starting is always a bit of a challenge anyway. I did install a new carb last year, a Holley Street Warrior, to replace an Edelbrock that always gave me issues. The car runs smoother now but does sometimes have a bit of a hesitation if you hammer down.

Whoever had the car before me was a little bi-polar about modifications (they welded the rear-diff, tore out the A/C components, pulled off the kickdown, etc) I guess to run it straight line, so I've been trying to undo some of the more insane modifications they did while making responsible upgrades when needed to balance it back out. I was told they changed the camshaft but have no clue as to what they did or what's in it now (if anyone has any ideas about how to confirm any of that without tearing the engine down I'm all ears) so I don't know if the factory fuel pump at 25GPH and 6PSI is what I need or if I need to upgrade.

Any suggestions would be appreciated!

72 Mach I - 302 w/Holley 4-Barrel - Automatic - no A/C (yet, planned upgrade soon)
 
Not being a MD, I don’t understand the torn artery assertion. I’m assuming it’s bad, I just don’t know if it’s one of those horror movies with squirt blood references or your saying the carb isn’t getting any fuel?

No fuel is a bummer. If you’ve had it long enough to drive it, short cruises, and even shorter distances with tires smoking, you probably know it enough to answer the question. I would vote, if it was working, don’t change it, as in, put the same pump back on it. They're not too expensive and easy to change.
 
I run the basic mechanical fuel pump like you get at autozone. On all my old cars from inline 6 to 302, 350, 351, and 429. They work fine with the holley and edlebrock carbs. Unless you are running your 302 at like 9k RPMs, you probably wont be needing any sort of high volume aftermarket pump.

Another benefit for aftermarket ones is its easier to connect custom lines if you want to run the AN style connections. I could see wanting to use one of those fuel pumps for that reason.


When you say yours pours out fuel like an artery, are you saying it has a leak somewhere? The fuel system is supposed to be closed and pressurized. Where is it pouring fuel from?
And can you share a picture of your current pump? Is it as electric or mechanical one? And is there any sort of pressure regulator between the pump and carb?
 
It's a mechanical pump, no upgrades there. And by pumping like an artery, I mean really pumping. I'm pretty sure it's a Carter M6588 that's on it now, straight connection with no regulator, and from where the aluminum meets the brass (or whatever metal the bottom half is made of) it's sending a spurt of fuel 3+ inches and hitting the bottom of the motor with each cycle. I'm thinking that it may be cracked on the backside, we had an really cold weekend a few weeks back, into the negative temperatures which for South Louisiana is crazy unusual, and maybe that caused it to crack. I haven't been able to get under it and confirm that's the issue but that's my best guess.

Thanks for the recommendations. I was getting so much conflicting info from the few people I know who still work on cars this old and none of the research clarified. I think the M4009 would be a great option. Just enough of an upgrade to make life easier down the road and I won't have to get crazy with the replacement.
 
I am another Mustang/Shelby lover who is in favor of using the regular mechanical fuel pump unless you have a specialized fuel delivery system that requires a lot of pressure (fuel injection). I have only used replacement pumps from AutoZone, and in my case they have worked fine. But, the Carter M4009 having received the Jason and HemiKiller approval tells me it is a fine choice. The fuel pumps are not usually hard to replace, but if you have the fuel pump eccentric on the front of the camshaft timing gear in its "high" position you will be fighting with the pressure on the pump's actuating lever all the way. It is better to bump the engine a little at a time until the pump eccentric inside the timing case is in a "low" position, which takes all pressure off the actuating arm.

As for the pump's diaphragm having a leak, here is something I feel you should be aware of. When the fuel pump's diaphragm begins to leak there are two places the fuel can go, and in both cases it no longer goes where it should be going (carburetor fuel bowl after passing through the fuel filter before the carburetor). Either wrong place where fuel can go is bad, both is worse. One bad place for it to go is when it begins to pour liquid gasoline onto the ground. First, it is a fire risk, and when the external leak is "minimal" it wastes fuel.

The 2nd place it can go is into the engine crankcase. This is rather insidious as unless you know how to ascertain there is gasoline being leaked into the crankcase a person can be blissfully unaware the gasoline is contaminating the engine oil, and preventing the oil from properly protecting the inside normally lubricated surfaces of the many engine parts. The way I test to see if gasoline has invaded the crankcase is to pull the engine oil dipstick and simply sniff. If I detect even a hint of gasoline I know I better be changing the oil and filter. In my case personally I only sniff to see if it is evident there has been fuel contamination. Despite what I do or don't smell I always opt to change the oil and filter anyway just in case any occurred but I was not able to detect it. Call it cheap insurance.

It is also possible a leaking fuel pump can both leak externally, and into the crankcase. This is no time to make assumptions and overlook the potential for fuel contamination inside the engine. Fuel contaminated oil is capable of letting an engine become needlessly destroyed if the oil and filter are not changed.

Personally, I feel with these older cars the rubber fuel hoses at the fuel pump and fuel tank ought to be changed when the pump is changed, as it is likely what you have are the original fuel hose. And, unless you KNOW the fuel filter and rubber fuel filter hose are fairly new the fuel filter rubber hose ought to be replaced also. I change fuel filters and its rubber hose with every tuneup, every 2-3 years. Too often I have seen under-hood fires caused by a fuel filter's rubber hose becoming cracked and leaking liquid fuel really close the ignition distributor. When that happens those folks who are insured are the ones where the car it totaled. The less fortunate ones are those with no such insurance, or those with insurance where the car is not totaled. I have done a lot of those under-hood fire jobs in the past, and it is never pretty. The insurance adjusters would ask me to installed used parts from a wrecking yard, or to just "clean up" items scorched by the fire, then use graphite spray to over any discoloration, etc. More than once I had to tell an adjuster that a threat of never future under-hood fires to our dealership would be fine as I am paid "straight time," which costs me opportunity income as compared to be pad on a flat-rate basis, and I would also be relieved of having to deal with "someone" (adjuster) who is pressuring me to do a job on the cheap, as opposed to doing it correctly. I would also let the adjusters who pressured me know their little threats of moving the job at hand to a different shop was not going to intimidate me as in California the customer was able to select the shop doing the repairs, and if they persuaded a customer to have the job moved elsewhere I would be happy to let them know why it is their insurance company wanted to move it somewhere else. For the record, when I cleaned up an under-hood fire I did it right. Using new parts, and anything that was scorched got hot enough to require replacement even it is was apparently working at the time (alternators, for instance).

If you have not yet begun to replace the fuel pump, and the rubber fuel lines at the pump and fuel tank, Lynda and I made a YouTube video showing how to do it, kind of. I say "kind of" because there is a section, the actual pump replacement itself, where I thought the iPhone was in record mode, and it was off. But, there is enough content with the rest of the work to make watching it worth the time - IMHO. The engine in the Mustang where the fuel pump was replaced is a 302, which is essentially the same as a 351W. But, the 351C has a slightly different pump mount bolt orientation/pattern - otherwise everything else is the same. Here are the YouTube video links:

Rubber fuel line replacement at the fuel pump and fuel tank:


Preparing the new pump and gasket for installation:


Removing the fuel pump:


As explained above, the video showing how the new fuel pump was installed is missing due to an OFU (Operator Error) with the iPhone.

The complete set of the above videos in a single file:
 
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Holy...crap! I can't tell you enough how much I appreciate this post. I was planning on changing the oil anyway but never thought about fuel contaminating the crankcase and very well may have put off the oil change until it warms up a little and I had more time. Now I'll make sure that its done as soon as I swap the pump regardless of whether I smell gas or not (which I'm doing first thing when I get home). The lines from the current pump to the carb are new, were replaced when the new carb went on last spring, and I thought it was a good idea to swap the lines from the tank to the pump so your videos are a life saver there.

I've looked into the Carter they recommended, per CJPony parts it's not compatible with a '72 302 but I'm sure that's just manufacturer specs, is there any modification I should be prepared for? At least eyeballing the pump it looks like the same mount and fit but I haven't seen any specifics on retrofitting to a later engine.
 
Holy...crap! I can't tell you enough how much I appreciate this post. I was planning on changing the oil anyway but never thought about fuel contaminating the crankcase and very well may have put off the oil change until it warms up a little and I had more time. Now I'll make sure that its done as soon as I swap the pump regardless of whether I smell gas or not (which I'm doing first thing when I get home). The lines from the current pump to the carb are new, were replaced when the new carb went on last spring, and I thought it was a good idea to swap the lines from the tank to the pump so your videos are a life saver there.

I've looked into the Carter they recommended, per CJPony parts it's not compatible with a '72 302 but I'm sure that's just manufacturer specs, is there any modification I should be prepared for? At least eyeballing the pump it looks like the same mount and fit but I haven't seen any specifics on retrofitting to a later engine.
I am certain the other members of this forum are appreciative as both you and I for the information that is shared. I have learned a lot from our fellow enthusiasts on this forum, and deeply appreciate how it is we get along so nicely as a group - with only a few exceptions that I "almost" recall..
 
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