351C Fuel Delivery Problem

[Rumblefish]

Was driving my 1971 mustang yesterday and it started acting like it was running out of gas. I had full tank.  It was sputtering so I pulled of to side of road and looked under hood at my glass see thru fuel filter and saw it was dry. I replaced the fuel filter with a new one and on the way home, it sputtered again. Today, I replaced the mechanical fuel pump. Took it for a test drive and the fuel filter ran dry again. I limped the car home and now I'm kinda stumped. My motor is 351C, .30 over with mild cam and 2v heads. Edelbrock intake and 600 CFM carb. I installed a new fuel tank and sending unit with new hoses before I fired the motor up last year. Any ideas?

 

[Don C]

Rust in the fuel line, did you see any in the filter?

Bad (dirty) tank of gas clogged the sock on the fuel inlet in the tank.

Rubber hose in the fuel line disintegrating.

Hole in the metal or rubber fuel line letting air in.

 

[Rumblefish]

Don: Yes there was some debris in the fuel filter, it kinda looked like rust. I was thinking maybe the steel fuel line from rear of car to engine compartment may be plugged. I'm gonna check it out this weekend.

 

[Carolina_Mountain_Mustangs]

Take your fuel line loose at the tank and at the fuel pump. Put white paper towels in a glass jar and put the end that connects to the fuel pump in the jar and towels. Blow compressed air from the rear of the car and see what comes out. Also where the fuel line come through the inner fender under the master cylinder that line can kink and stop fuel.

Did you use ethanol resistant hose and replace all pieces from tank to carburetor with it?

Before installing fuel pump you should check with a vacuum pump like used to bleed brakes. I have had brand new pump have bad diaphragm in last year.

Also check you oil and if it is higher than it should be the fuel pump probably pumped the gas into the engine oil pan if it had a bad diaphragm. Of course that means new oil, filter and check out the fuel pump.

 

[Rumblefish]

I used fuel hose for the tank connection to the steel lines and everything else up to the carb. I'm gonna try the compressed air to clear the lines. Thanks.

 

[Don C]

If you didn't use ethanol rated/resistant rubber hose, and you filled up with gas with ethanol in it, the ethanol disintegrates and swells it inside the hose, plugging it up.

 

[SVO2SCJ]

You said you were going to "clean the lines" ....IF THE OLD TANK WAS VERY GUMMED UP (and in the lines) AIR won't do it.

Get a spool of WEED WRACKER trim line remove, line from the tanks (Plug output tube) and sit and feed the trim line into the fuel line. Push and turn , and removed . See how far you went by comparing to length of tube. Continue from the rear.....then switch to the front. After removing the gas line to the pump -feed the trim line and repeat. Then put a clean oil pan under the back, I would then FLUSH the line (from the front) and NOW USE COMPRESSED AIR to clear the line. TAKE A PHOTO AND POST IT of the stuff in the oil pan!

Mark

 

[Rumblefish]

So I followed your advice and blew compressed air thru the line from the rear up to the front at the fuel pump connection. At first, there was blow back as the air didn't want to go thru the line, then suddenly it pushed thru and I got about 2/3 cup of fuel and a bunch of rusty black sediment and tiny rocks.  I think it's clear now. Hooked the lines back up and taking it for a road test. Thanks again for your help.

 

[Rumblefish]

Mark, here you go.

 

[Rumblefish]

 

[NOT A T5]

I might just want to add... see through glass fuel filters are a bad idea, they are unsafe, can leak and start a fire!

 

[Fabrice]

The jar says replace your fuel lines...

 

[Rumblefish]

Back to square 1. Car was sputtering today and I checked my glass fuel filter and it was empty again! Some light debris in it, but not that bad. Looks like I'm gonna I'm gonna buy the Weed Wacker trim line and go that route. TY for the information.

 

[SVO2SCJ]

Once done with "cleaning better" lets keep talking !! There is a thread on the FE forum right now, dealing with miss matched dowels/eccentrics and the same issues. Seeing you "rebuilt" the motor that maybe a question IF THIS persists.

DISCLAIMER (some know I sell the Nascar roller eccentric) ...so BEFORE people jump to "selling that $125 part" I just wanted to TALK about the issues people have from aftermarket companies "that supply one size fits all" parts or ASSUMING builders know to check sizes/changes to designs!

Mark

 

[Hemikiller]

What kind of carb do you have? If it's an Edelbrock, might want to pull the lid as some of that garbage you had in your lines is probably now in the carb.

 

[Rumblefish]

Edelbrock 600. I will check it out. TY

 

[Fabrice]

@Rumblefish

Do not waste time/energy cleaning that line, replace it! Cleaning a line is for cases a foreign liquids or rubber debris are in the line and when the line is relatively new.

Its not gonna remove the rust and magically make it shiny in the inside. You will be back to square one before you know it.

I've removed mine when I've moved to EFI, not giving out any rust to the fuel, nicely painted, they were "looking" strong.

But man it was a wrong assumption, if you've seen how fragile they were once out of the car, you would never want to let this 50yo piece of cheap equipment ruin your fuel system ever again. I will not even mention the hazardous situations you could get if you while cleaning remove a big chunk of rust where the metal is very thin already once under pressure again.

You can buy preformed lines if you are on a picky original restoration, but there are so many cheap alternatives and its so easy to install...

https://www.amazon.com/Allstar-ALL48328-Foot-Coiled-Tubing/dp/B006K8MC34

https://www.ebay.com/bhp/fuel-line

Anyway, my 2 cents. its your car.

 

[Rumblefish]

Fabrice: Thank you. I was thinking it over last night, Part of me wanted to pump vinegar thru the lines to remove rust/debris and the other part wanted to just replace old line with new flexible aluminum line. I will check out your suggested links. I'm leaning on replace with new line.

 

[Don C]

Do not use aluminum tubing for fuel lines, or anything else in a car. The same water that rusted your steel line will eat through the aluminum, plus aluminum tubing is prone to cracking from vibrations. Use copper-nickel for fuel lines and brake lines, very strong, vibration cracking resistant, and no corrosion/rust. Here is an example, another is NiCopp

https://www.thestopshop.com/collections/copper-nickel-cupronickel-tubing-kits