Chevrolet 350 Mechanical Fuel Pump Replacement

So I finally get the 1979 Monte Carlo running and take it out for a spin.  I pull up to a stop sign and the car just putters out and dies.  I am able to start it again and get it to move but it’s under powered and when I get to the next stop it dies again.  At first I’m thinking that the carburetor is just misadjusted so I limp it home and go through the initial setup procedures as posted on Edelbrock’s website.  Turns the idle air screws all the way in, then back them out 3.5 turns, and adjust from there.  I get the car started again and it just dies.  After a couple of more attempts, I notice that the fuel filter (It’s a clear one) is sputtering with fuel as the car starts to putter and die.  Easy enough, the car is not getting any fuel, must be the fuel pump!

The engine in this car is a Chevy 350 with a mechanical fuel pump.  The pump I purchased is an Airtex unit that was for a 1979 Chevrolet Camaro.  Since I have no idea what motor is actually in the car, I just looked at the pictures and picked the one that was as close a match as I could.  This particular pump had two bolts holding it onto the engine, a fuel inlet (which was clamped on), and an fuel outlet which was a ¼” fitting.

The first step to pulling this off is to disconnect the fuel lines.  I took a 5/8” wrench and disconnected the ¼” fitting.  I then used a pair of needle nose pliers to squeeze the clamp and remove the fuel inlet hose.  There may be a little bit of fuel that spills, but in my case the pump was bad and there was very little fuel in the pump.

Remove The Lines From The Fuel Pump

Remove The Lines From The Fuel Pump

Using a 5/8" wrench remove the fuel outlet line. The other line is clamped on. The Other circles are the locations of the bolts that hold it to the motor.

Using a 5/8″ wrench remove the fuel outlet line. The other line is clamped on. The Other circles are the locations of the bolts that hold it to the motor.

I then unbolted the fuel pump from the engine.  There are two 5/8” bolts that are holding it in.  Just unbolt them and the fuel pump will come off.

Removed Pump!

Removed Pump!

You will want to clean any of the old gasket that is remaining on the engine off and make the mating surface as clean as possible for the new pump.

I followed the instructions that came with the Airtex pump and packed the inside of the lever portion of the pump with grease to lubricate it.

I then sprayed some copper gasket sealer on both sides of the gasket to get a good seal to the engine.

You can see the gasket on the floor, it's already been covered.

You can see the gasket on the floor, it’s already been covered.

I put the bolts through the holes of the new fuel pump and mounted the copper sprayed gasket.

New Pump Ready For Install!

New Pump Ready For Install!

The next part is the trickiest part of the whole procedure.  There is a small rod that rides on the camshaft that pushes on the fuel pump lever to create the suction to pull the fuel from the gas tank.  You will need to turn the motor to a point where you can slide this rod up and out of the way so you can get the fuel pump lever to be underneath it.  I was able to turn the motor and push the rod up, I was very gentle with it and it stayed up.  I then maneuvered the lever into the hole and bolted the pump to the motor.  It is very important that the fuel pump lever be underneath this rod, that is how it works!

The fuel pump lever slides underneath this rod. The rod slides up into the motor.

The fuel pump lever slides underneath this rod. The rod slides up into the motor.

Once the pump was bolted up, just re-connect the fuel lines and test.  It may take a couple of tries to get the car to start because the new pump will need to pull fuel from the gas tank.  If it was installed correctly, your car should be running much better!

New Pump Installed!

New Pump Installed!

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