Well, if it ain't one thing... it's 6 more with two in the wings...
out for a ride today to see if all my ignition changes made a different in the stalling situation
aaaannnnd the mechanical fuel pump died a hasty death. after waiting 5 hours and going thru
3 towing co.s I got it back home... now I'm wondering if this was my problem all along starting to happen

anyway
got to replace it... my question mechanical or electric ?? pros/cons ??

it's a 460 carbureted with an dead eldebrock mechanical pump... changing to electric will require some major plumbing changes
but if it's more reliable... it's worth it

educate me on fuel delivery ???

john

 

For what it is worth, my fleet uses stock mechanical. I would want to know WHY the fuel pump conked out before deciding direction because your next pump (regardless of selection) may be headed down the same path if the root cause is not determined and addressed.

• Is there a leak in the fuel line causing it to draw air?
• Did the diaphragm tear due to new gas or old age?
• Did the valves/seals dry out or get contaminated with grit/rust?
• Did you simply run out of gas?
• Is the tank petcock closed or plugged?
• Vapor Lock?
• Bad gas cap?

 

For simplicity I vote for the mechanical pump. Mine went out while at CTC a few years back. Easy fix under a big oak tree and nice Gulf breeze!! Thank goodness most all auto parts stores carry the pump I needed. Good luck Buddy. Hate I won't see you next week at CTC 2022. Steve

 

Mechanical pumps have been very reliable on millions of engines for many years. I wouldn't hesitate to replace your dead Edelbrock with a stocker from your local parts house. You just have to get the right one for your application. There's a lot of choices for the 460. I just went through some of that on my 87 F250. Electric pumps have their place, but also come with their own issues to deal with, safety being one of them.

 

Edelbrocks are rebuildable aren't they? Getting an over-the-partscounter fuel pump seems to be getting as questionable as rebuilt starters and alternators. I would take it apart and rebuild it.

 

I don't understand the love for mechanical pumps, particularly with gasohol in the picture. I'd bet all of us on here own a modern vehicle with an electric pump that typically lasts 100K+ miles with no troubles. I've been running an Airtex electric pump for 17 years and have not had a single fuel-related problem with it. I did have a regulator diaphragm develop a leak, which was an easy and cheap fix.

With an electric pump you can (should) mount it back near the tank, away from all the heat of the engine. You also have flexibility on how you route the fuel line, away from hot components. If your tank has a return fitting, even better. There is no chance of a ruptured diaphragm filling your crankcase with fuel like with a mechanical pump.

Carter and Holley both make good quality pumps. You likely want a regulator, although some electric pumps have them built in.

 

All my modern DD have in tank return style electric pumps, many happy miles. 1 failure 15 years ago was $700, towing involved. 95 truck 2 fails but dual tanks so no wrecker but did involve trading in to be done with it. Both style pumps have pluses. Mechanical is easy roadside repair with a few wrenches if you have a spare. If you go electric, do it safe. Inertia switch and oil pressure trigger switch.

 

I have used Holley red pumps on all my projects for decades...don't ever see a mechanical pump in my future.

 

ok I went with mechanical...because it was easier than changing all the plumbing... all installed... now

how long should it take for the pump to prime and get some gas to the carb..it seems to be taking longer than I thought it would

j

 

You could put a slight amount of pressure in the tank to help it, just a few pounds. Or prime the carb a little.

 

a stump the dummy question... hint I'm already stumped.

in regards to my fuel delivery problem... engine 460, mechanical Edlebrock 1726 mechanical pumps.. my old thinking was that mechanical pumps were gravity fed (my guru taught me this) BUT My tank outlet is 8"
lower than the fuel pump inlet... so no gravity assist. do mechanical pumps have enough vacuum to pull fuel out of a lower tank ?? crude sketch shows my system

rubbedr 3/8" line leaves mustang tank and turns up to frame rail... 3/8 hard line from there and it runs pretty flat along inside of rail and raises slightly to top of rail at engine
SS braided line from hard line to the fuel pump

don't know why this problem started now...been doing fine for over a year. I've checked all lines for blockage..filter is clean. no blockages, kinks, or bends in the lines...help the dummy
will this mech pump pull fuel and if so, why did it stop

 

With the Flathead V8's, the stock location of the mechanical pump is just about the same height as the top of the fuel tank. Your rise of 8-9" should be no problem. The mechanical pump does indeed operate by drawing a vacuum. There were many things to check to ensure that it can draw the necessary vacuum:

 

• Thanks Bmoran for all the suggestions and gives me things to ponder and check out for sure..
• Is there a leak in the fuel line causing it to draw air? nothing physical that I can see... but might seal off the line and pull a vacuum on it to see
• Did the diaphragm tear due to new gas or old age? took pump apart and found so sign of break or hole in the diaphragm.. It's a Edelbrock pump with a seriously thick diaphragm
• Did the valves/seals dry out or get contaminated with grit/rust? On inspection, diaphragm was still very flexible and all the internals in the pump were clean and rust free..
• Did you simply run out of gas? nope, had 3/4 tank when problem started...never less than 1/3 tank
• Is the tank petcock closed or plugged? none at tank .... but will be as soon as UPS arrives...tired of draining the tank
• Vapor Lock? engine cold when testing
• Bad gas cap? might look at that... I've done the testing with gas cap both on and off the filler... so it's doesn't seem to be a vacuum problem at that point

AFA a vacuum or pressure test... have not done but holding my thumb over inlet and pushing down the actuator I feel suction that does not fade until I remove my thumb

I'll hook up a vacuum gauge on it next and pressure gauge on output . That should either show the failure in the pump or pass it as good. How much vacuum should I see ?? haven't been able to find this info anywhere...
It was too late to get Edelbrock tech on the phone Friday evening...I'll try Monday am This pump is only a couple of years old and less than 1500 miles on it
and I understand about quality control even on new parts...things just fail sometimes. I've had a Ford pump that had over 300K miles thru three different engines
and it was still working when I sold the truck but had another OEM pump that failed out of the box too.

I've got a good friend that is a guru and he is adamant that you have to have a gravity flow from the tank to the pump...to feed the pump or it will never work and I understand
his thinking... but this truck has been set up this way since the start and hasn't had a problem till now... AND if it stays that way I'll never have gravity flow due to the
way the hose is routed up to the frame from the tank.

 

Gravity flow: I'd have to measure height from ground on my truck but 53-55 trucks have the tank between the left frame rail and the driver's running board and the top is level with the frame rail. So I'm thinking the bottom of the tank would be lower than the mechanical fuel pump.

 

John, I'm not disparaging your guru but my truck is set up basically like yours and I have had no problem feeding fuel through mechanical fuel pump for 10+ years now. Of course I'm only feeding a "little" 351W and not a big honking big block!! Over the counter 1996 Bronco pump bolts right up to mine. Good luck Buddy, Steve