How to test Mechanical Fuel Pump using common gas can- Squarebody C-10

Testing the fuel system by hooking the pump up to an auxiliary tank. The fuel pressure is dipping below 2psi and im not sure if its the pump or a clogged fuel line.

[@leonardlacasse3730]

would imagine zipp trying a short leg on the end of the hose might be a good idea to keep the hose from bottoming out. Great set up! Thanks

[@christophermalone5563]

Going through the same issues now with my 82 Jeep wagoneer videos very helpful and following you cuz I need to do the same thing with my gas tank

[@KourtneyCarter]

Glad I found this! Will be doing this!

[@onrdetailingnews802]

On cars this old i rather just replace the fuel pump anyway only 2 bolts save more time good video tfs

[@mechanuts7191]

I agree 100% bud...thats why the pump was new. I was more checking to see if the lines were bad..... Obviously this wouldnt have worked with a bad pump right...but you knew that already,LoL

[@onrdetailingnews802]

@@mechanuts7191 yup tfs

[@cashlifefilms1059]

tried this on my 87 firebird but im still not getting fuel to my carb

[@gtrsteve]

Wait, what? What are the connections? Gas Can to fuel pump intake, then to carburetor? Is there a return line from the carb back to the gas can or something?

[@mechanuts7191]

yes and yes

[@keithbrooks5698]

Hi I have an 87 Camaro have taken the TPI engine out, now have carby. When you put the relive valve in at 5.5 psi do you also have to have a return to the tank. Hope you can help.

[@mechanuts7191]

So.... Most (not all)factory GM setups pre 1980-ish had no return on the pump. Once it was discovered that cavitation and fuel vaporization were a problem with unleaded fuel they changed over to a return line setup. That being said it really depends on the pump. If you have a new old stock GM pump they are pretty good about relieving pressure through internal means...however anything being produced now for under $200 is a crap chinesium pump with pva plastic diaphragms that DO NOT work well without an external regulator. My setup is a return style Carter pump( on my 3rd in 8 months...dont buy carter anymore) with a regulator in line with the carb post filter. I added the regulator ( @ 5.5psi) because even though its a return style pump it does not regulate pressure properly. I have not found a modern mechanical pump that regulates pressure precisely enough for an edelbrock to be happy and therefore have to add the in line regulator. The regulator I use is for a returnLESS pump but works well as I have it set up. SUMMARY: Buy a 3 port pump ( return style) from your local parts bin( $30 ) so that you have a local warranty...mate that to a static in line pressure regulator ( mr gasket $20 ) and YES run a return line off the pump to the tank. This will give you enough fuel to support at least 350hp and maintain 5.5-6psi

[@Handicap-able]

What size hoses did you use? I am about to try this but do not have any hose so have to go buy some....

[@mechanuts7191]

3/8 fuel line

[@davidrowland2354]

What issues were you having

[@fvrrljr]

HAHAHAHAHAHAHAHA you're a Mad Super Genius 👍been there done that 🤣😂🤣 other way is to connect a fuel pressure gauge, if you do not have fuel gauge try this method. if doing by yourself or with a second person to crank engine (other ways to crank engine alone) get a gallon jar (plastic preferred) disconnect hose from fuel pump or at carburetor (which ever is better access) put hose to gallon jar, crank engine 30 seconds, that should give you 6 oz, if not, time to replace fuel pump (this method is on mechanical fuel pumps) i don't know how many ounces would result. on my RV when i've run on empty i have to bleed the line from air. disconnect hose at carburetor, let the electric fuel pump gas into a small water bottle, reattach hose and i'm good to go.

[@mechanuts7191]

I do have a gauge but it didnt tell me anything other than ...Hey you have low pressure/no pressure. In this case I was trying to determine if I had pre-pump line blockage or a pump failure. Ive used the LPH method on electric fuel pumps but it isnt as useful anymore on the mechanicals due to the inconsistent flow and pressure ratings even on identical pumps. Modern Mech Pumps Suck so bad now it makes me angry. Well at least the pressed ones under $100 do. I suppose a billet pump may fare better. I.E.one pressed mech pump may flow at 70lph @5psi and one that came off the same assembly line may be a choocher and test to 90lph @ 7psi. however Pretty much all modern electric pumps are within +->2% of advertized flow/pressure so it works great with them. Speaking of mechanical pumps...Im about tired of replacing mine every few months or so. Ive been through 5...Yes actually 5 since aug 2020. They all seem to eventually weep where they press them together. Im gonna have be doing a sniper setup soon so thankfully ill be done with the mechanical pumps at that point. Anywho thanks for watching and be well!!!

[@fvrrljr]

@@mechanuts7191 i totally agree with you, besides this new gasoline messus up the rubber components. i have a '68 Slant Six with 330k original miles and started givine me the same problem. i admired the way you installed the gas can 👍 thanx for the reply

[@blackjesus1205]

I read online that u don't have to have the return line is that true

[@blackjesus1205]

And it's pretty hard to tell what's going on there

[@mechanuts7191]

Depends on the setup. WHat are you working on

[@curiousgeorge986]

I'm going to attempt this my with 7.3 Powerstroke diesel. Any tips?

[@mechanuts7191]

use fuel injection rated hose. The pump on a diesel may collapse a softer hose Also im sure its obvious but dont try this with the high pressure side,LOL

[@curiousgeorge986]

@@mechanuts7191 isn't the high pressure side the lower port on the fuel pump

[@mechanuts7191]

Dont know a thing about the 7.3

[@rufelestrada9791]

This very technique saved me on my Ford 7.3 powerstroke! I rebuilt the entire top half of the engine and replace the fuel tank, fuel pump, and lots more, before I tried this trick, only to find leaky fuel line that sucked air.