I have a 79 Corvette that had been stored for almost 10 years that I recently started to restore. After checking the fluid levels and replacing the battery it started right up but would only run for about a minute and die, but after sitting a while it would start and run again for a minute or so. It had plenty of spark so I took off the gas line to the carb and sometimes could get gas by turning it over and sometimes no gas. I decided to order a new fuel pump and a new steel line to the carb and the rubber hoses that attach from the fuel pump to the steel lines to the tank. While waiting on these I tore down the front suspension and steering and sandlblasted, painted and replaced all the bushings, ball joints and tie rods as well as replaced the brake calipers and brake lines. While I had it apart I went ahead and put in the new fuel pump and lines.

When I tried to start it there was no gas from the fuel pump. I thought maybe I had let the rod slip when I installed the fuel pump, so I took it off and reinstalled it and made sure the rod was retracted when I put the pump back on. Still not pumping gas so I need to know how I can check the pump. If I know the pump is working I can start looking at the gas tank and the rubber hoses on that end, but I would like to rule out a problem with the pump first.

My first thought is to sit a can of gas on the ground next to the car and run a rubber gas line to the fuel pump and see if it will pick up the gas from the can. Is this a workable test or is there a better way?

Thanks for all the info to an earlier post about what manuals I should buy. I ordered those suggested and they have been exactly what I needed. It has been over 30 years since I have worked on my cars to this degree and it has been a lot of fun. Back then it would have been great to have a resource like the internet.

 

if you disconnect the line from the pump that is coming from the tank, do you get gas flowing?

 

Its possible that you need some fuel in the line to get pump to work. Its also possible that you have built up vacum in tank and it wont let pump siphon fuel out. Try running it without gas cap on just to eliminate that possibility.

 

There was when I took off the original fuel pump, but none now. If the line is empty and the pump is not working would there still be gas in the line, or does it need the suction to get it started.

 

I added 5 gallons yesterday and left off the cap with the same results.

 

The main line should gravity flow gas to the pump. You might want to check the rubber hose to steel line connection under the tank. I would also look in the tank to see if something is clogging up the pickup.

 

I agree. The tank should empty by gravity if that pump inlet hose is off and not crimped or plugged. Something amiss at the gas tank end.

 

An easy way to test the pump alone is just to have a helper crank the engine while you have your finger over the pump suction port. You will feel a lot of suction.

The tank line won't drain by gravity alone, it needs some syphoning help.
On a 79, the pickup tube/sock/screen is at the bottom of the tank, but the outlet is at the top, so you have to get some syphoning action going first to put the fuel over the hump.
Make sure the car is level with the gas cap off, attach a 3/8" hose to the end of the metal fuel line on the frame rail by the pump and suck on it. After a few seconds you should get a lot of gas flow. It might be easier just to test for obructions to first put a couple of lbs of air pressure thru the line into the tank, only a little because you don't want to blow off or destroy the screen. You should hear it buuble in the tank. You could alternately put some air pressure into the tank fill neck closing it off as best as possible with a rag to put fuel over the hump.

The only other reason you won't get fuel if the metal line is clear would be from the hoses from the top of the tank to the metal fuel tube being cracked enough to prevent suction from the pump. Happens because the old lines get hard and brittle.

 

Thanks for all of the suggestions. I ran a gas line from a gas can to the fuel pump and cranked it over a few times and it is pumping gas, so the fuel pump is good. It does appear to be a problem in the tank or the rubber hose coming from the tank to the steel line. I tried blowing compressed air back to the tank, but their seems to be an obstruction.

I had planned to remove the tank and clean it out and replace the rubber hoses but just not at this time. This job just got moved up to this weekend. Thanks for all of the suggestions and any hints on removing the gas tank?