I had a mechanic replace the fuel pump on my 79 c3 today. No fuel is reaching the carbuerator after a lot of primimg. Is it possible to put the pump on wrong or is it just a faulty pump as he suggests.

 

Both are possible.

 

 

I do not mean in anyway for this to sound harsh, but this is a prime example of why sometimes owners need to do things themselves.

Of course I realize everyone doesn't have the same skill/comfort level or time, but barring any physical impairments that might keep someone from doing an intermediate skill job as this one, YOU would know for sure if you had the pushrod oriented correctly with the fuel pump arm or not, or if it was the pump that was bad.... instead of having to take someone else's word for it.

I don't want to make assumptions, but perhaps in the future, ask here first before paying anyone to do anything.

 

No offence taken...my back won't allow me to go low.

 

Which pump? It should be an ACDelco (likely Airtex) 41240 (GM 6441240).

There's also a very slight chance that your cam has wiped the fuel pump lobe, but that is unlikely.

Why did you replace the old pump?

 

Maybe the filter sock is clogged, and the issue is just still there.
Any hole in a hose and it sucks air................
He dropped the push rod, and it's on the a arm.
Wrong pump hoses.
He is "not so good."

 

I hear ya... none of us are as young as we once were.

 

Also very plausible

 

There is a fuel delivery mechanism that goes from a pickup in the fuel tank to an inlet to the carburetor. If you asked the mechanic to change the fuel pump without understanding whether that was what was needed, you got what you paid for. If you asked the mechanic to diagnose why no fuel was getting to the carb you might have gotten a different result. We don't know here what was wrong in the first place and why you thought you needed the pump.

 

Let's start here...

 

The most likely issue is that your mechanic replaced the rubber hose going from the metal line from the fuel tank to the pump with a piece of 'regular' fuel hose. That hose NEEDS to be a properly molded hose, so that it will not 'kink' and block fuel flow. Take a look at the fuel pump area and look for a short hose with a double curve in it. If it looks to be kinked in one or two spots, there is your problem. Order the correct MOLDED hose for your car and replace it.

If that is not your problem, the mechanic has messed up something that is a relatively simple job. You may need another set of 'skilled' eyes on your car to diagnose the problem (since you can't drive it to another mechanic).

 

How about a clearly faulty pump that was replaced by an NOS service replacement, worked immediately, again the next morning, drove 40 miles perfectly, parked and a couple days later come back and it will not start at all, very obviously not getting any fuel.

The push rod slip off the arm?

 

no. infant mortality. part lived just long enough to screw the car owner AND the mechanic. and we need to keep in mind. ALL pieces of machinery we use are trying to figure out how to screw us and fail on us every time we use them. they sometimes succeed...

 

The push rod can’t slip off the rod unless the swage holding the pivot rod came apart. I’ve had multiple Carter pumps all fail in the same spot and they may or may not run depending on whether or not the lever moves of it’s spot.

 

DT, how long is it sitting when this happens? I had my pump replaced some years ago by a mechanic. For the last couple years when the car sits overnight or longer I need to crank it a long time, maybe 30 seconds or more to finally get fuel. Changed fuel filter, had and still has the long one with built in check valve. This happens regardless of outside temps. I have even started it and ran it just a minute or so to insure I had flow from the pump but not enough time to generate any heat to verify that I have or not have an evaporation problem. Next day it takes a long time to start. I am thinking that despite the check valve in the filter the fuel is drain ing back to the tank.i think a ACDelco fuel pump has a built in check and I may have a knockoff without one. What I have resorted to do for now is pour an ounce ot two down the vent. Car starts right up. I am thinking that I now have enough fuel to run the engine and fuel pump to fully prime the lines. All theory on my part and feel free to correct me.
So, maybe try putting some gas in the fuel bowls and see if you get same results. Pump will flow more fuel with a running engine than just pump in of starter speed. This might prove that the pump is pumping but the fuel lines have a lot of emptiness to fill first. Would like to know if you have the same results.

Also, somewhere in this forum Lars offers a great write up on fuel siphon evaporation and such.

 

It is very possible to flatten the fuel pump lobe. That is a hard one to come to grips with. Lots of places to look suggested here.

 

The hose 7T1vette is speaking of is this one...


Fuel Line - Molded S
A lot of folks have attempted to replace it with a standard fuel hose only to find that the engine will still not start because the hose will kink. I once saw one where in order to keep the fuel line from kinking, the owner replaced his S-Hose with about 18" of fuel line in a big loop. It worked for a while but eventually kinked as well and almost always gets in the way of something else down there.

It's not a hose that most auto parts stores keep in stock, which is why I keep one on hand just in case. Most good ones (NAPA?) should be able to get it for you in a few days, or you can get it (and a spare ) from one of the Forum vendors.

Molded "S" Hose Kit
Paragon Number: 2050K
GM Part Number: 3994298
Molded “S” hose kit, fuel pump inlet from long line to pump (w/long fuel pump) w/clamps 6154.
Years 1970 - 1981
https://www.paragoncorvette.com/p-35...-hose-kit.aspx

Good luck and welcome to the Corvette Forum, I think you'll soon find it one of the handiest tools in your tool box.

GUSTO

 

Thanks for the details, GUSTO.....

 

And last but not least, guessing at the issue is:
Its likely a 3-Port pump. If O.P. is using rubber fuel lines instead of steel, perhaps the wrong fuel line went to the wrong port.