Starving 454

I have a 454 in my 55' Chevy truck with the gas tank relocated in the rear between the frame rails. I have had a problem with the engine starving for gas and dying at anything over about 30mph. I changed the fuel pump and the problem was still there. I added a small electric transfer pump to try and help with the volume and the problem is still there. Runs ok at slow speeds but starves out at higher speeds. Any ideas would be great. Thanks

 

Have you made sure that the lines are clear and that the tank has no obstructions?

 

Check filters, sounds like a flow problem, has it got the inline filter at the fitting on the carb?

 

If its a quadrajet, it does. Has the carb been apart in a while, the primary jets or shooters may be obstructed. Accelerator pump good?

 

Does the tank have a big enough vent?Try driving with the cap off the tank to see if there is a change

 

I have two inline filters, one glass at the carb and one paper type at the rear after the electric pump. I tried running with the gas cap cracked, no change. I have not checked the lines yet. I thought about changing to stainless lines from front to back.

 

Mainjets clogged

 

You have a filter after the fuel pump...... first place to look is any blockage between tank and pump.

 

Sock in tank or fuel filter inside carb inlets are clogged.

 

Take the paper filter that is after the pump out and replace with a piece of tubing and test. The filter should then be installed before the electric pump to keep crap from entering the pump. Replace the paper element first even if it's new.

You unfortunately didn't say what carb or carbs you are running but chances are there is a small filter where the fuel line enters the carb body, replace this as well, TR

 

What are you using for fuel line? I ran into a similar problem on a C10 and the rubber fuel line looked good on the outside , but had collapsed on the inside. I discovered this after replacing the fuel pump. Pull the fuel line off at the carburetor and run it into a container. Have someone crank the engine and see what kind of volume you have.

 

You may have a rubber line with a "flap" torn on the inside.
I'd cobble up some sort of fresh hard line (roll copper or aluminum, etc) to run the whole way from the rear pump to the engine. Make it safe, but it doesn't have to be pretty.

If you drive it and the problem goes away, replace the entire fuel line.

 

There is some great tec there Guy's !!!!!

 

Mechanical pumps "pull" the fuel. If there's a break in the line it's like drinking through a straw with a hole in it.

Where is your electric pump? Electric pumps must be located near the tank because they "push" the fuel.

 

Bypass the electic pump with temp hose, probably the quickest trial and error, I am sure you don't need 2 fuel pumps ? Just my .02 worth hope it works out

 

You might also check the pickup inside the tank and make sure it isnt loose and sucking air too .and if its a fuel cell type check the end of the pickup hose make sure it isnt sucking up to the bottom or sides of the cell and being closed . i cut notches in the end to prevent that

 

You should not need 2 pumps.
you have a blockage or you have a rubber line collapsing.

Start at the tank check the pickup/sock, install new line from the tank to the mechanical pump, blow out the new line before you hook it up, use a new metal line from the pump to the carb, change the internal carb filter.

If this does not fix the problem, you need to rebuild your carb.

Godspeed
MrC.

 

When did you install the filters, any problem before that? Glass filters are pretty but worthless, I'd get rid of that one. Fuel filters orientated in the right direction? Checked the carb internal filter? extra fuel pump added to the system will only flow what the mechanical pump allows.

 

I had a 427 in a 69 Chevelle wagon with the same problem.
Turn out it was the little cintered bronze filter inside the carb right at the inlet fitting.

 

I'd do a fuel pressure and volume test at the line close to the carb to see if the "back half" of the system needs attention before replacing any more parts.

carb friendly fuel pump test gages are also vacuum gages so are very useful

 

Maybe check the float level.

 

My mechanic friend told a story about someone putting zigzag papers in a tank for a prank. They would float over to the pickup and eventually restrick the flow. When shut off, they would float freely.

 

Holley carb - check float level, on a Street Avenger there are sintered bronze filters.
These can not be cleaned, only replaced.

 

Thanks for all the great tips. I found the problem when I inspected the fuel line. I had the rubber fuel line straped to the frame with a metal strap with a rubber protective lining. When I dumped the airbags a tab from the fourlink smashed the strap and pinched the fuel line. repaired the line, moved the strap and now it's fine. Thans again.

 

Good Job! Thanks for updating.

 

i was gonna say try runnin a jerry can up front but you found the problem good deal