As above. Last week I got my 'vette to start up after fighting with her a little, she didn't want to turn over but eventually ran. Before that she hadn't been started in maybe 3 weeks so I expected as much.
Today I wanted to get to a car show but no matter how hard I tried she refused to start. Battery was good, starting was cranking strong the whole time, spent about 20 mins trying. I manually pulled the accelerator line to give the carb fuel, and pumped the accelerator before and while trying to start it and she tried turning over 3 times but never turned on.
My fuel gauge read that I still some gas in the tank, and last time I drove it there was no fears of being low on gas. But when actually put light in the carb and looked straight into it as I pulled the accelerator cable, it stayed dry.
What are the chances it could actually be the fuel pump? Would a quarter tank evaporate in a week in the sun? I'm kind of at a loss right now but am willing to make repairs as needed, I just don't want to waste money on things I don't need.

 

At the front of your carb there is a TUBE, pour about an ounce and a half of gas into that tube, pump the throttle once or twice and see if it will start.

 

If the fuel tank is full and the fuel pump is bad, gas can't get to the carb. As Peterbuilt said, pour some gas into the tube with a turkey baster or a syringe and see if the car starts. Pull the oil dip stick and smell it for gas. Jerry

 

Pull the air filter, and look to see if the accelerator pump is squirting fuel as you cycle the throttle linkage. If you don't see fuel being squirted - as you move the throttle linkage from idle position to Wide Open - then the odds are about 95% that your float bowl is dry (the accelerator pump diaphragm could also be ripped).

What can cause a dry float bowl - well an empty fuel tank (not necessarily completely empty - but low enough that the fuel pump pickup isn't submerged) will do it, as will a bad fuel pump, as will a leak in the gaskets on the carb float bowl (primarily on a Holley Carb). A sticky float or sticky float valve is also a real possibility. If no acceleartor pump squirt - the next thing to do (at least the next thing I'd do) would be to disconnect the fuel line to the carb, and have someone crank the engine - while you look to see if fuel is being pumped to the carb by the fuel pump. .


GOOD LUCK

 

Ok yea I figured as much and just to make sure I didn't have a "well there's your problem, it aint got no gas in it" I went and got a gas can and put a gallon in the tank even though she read 1/4 tank.
I did remove the air cleaner like before and once again there wasn't any gas getting to the carb when I manually squirted gas with the accelerator.
As I was checking everything out I did follow the fuel lines across the car just to put eyes on it because I've never needed to do fuel work yet, but I do still need to work backwards and check where the fuel stops flowing, and I'll start with the connection to the carb like you said.

 

Seems like everybody is missing the other obvious starting issue, spark.

I didn't see you mention that you verified spark. I hope you aren’t just dumping fuel in it and washing the cylinder walls.

 

ok so I removed the fuel line going to the carb, where the fuel filter is, and some fuel came out that was left over but when I cranked the starter, no fuel came out if the line.

 

So - if you do indeed have a 1/4 of a tank of fuel - the odds are that you have a bad fuel pump.

Yes - there are other possibilities - for example its possible that you have a kinked or rusted through fuel line - or that the in tank fuel pick-up "sock" is totally clogged. But - did you ever hear the expression - "If you see hoof prints - think Horses not Zebras".

So - if I were in your shoes - I'd change the fuel pump - and be very thankful that the fuel pump failure left me stranded in my driveway - as opposed to the middle of Interstate 80.

 

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yea ill order one this week and get it replaced sometime soon. I'm just confused on why it started the previous week then suddenly decided to die. What are the chances the battery doesn't have enough juice to power the pump while starting the engine? Seems like a longshot but idk why a working car would decide to just *stop working*

 

Hello. If you still have a stock type mechanical pump you don't have to have any "juice" to make the pump work. The engine turning over is what makes the pump do it's job. The pumps have a diaphragm that can rip and case the pump not to work. You may want to check your engine oil as Tampa Jerry said for gas. Smell test should work. That can happen under some circumstances of pump failure. If so change the oil before running. Good luck.

 

Did you try to dribble some fuel into the carb, as suggested above?

A running engine may make a marginal fuel pump work well enough to stay running, even if the starter won't.

When you get the pump off, take a look at the pushrod, too.

 

As mbp said C1's, C2's & C3's came with mechanically driven fuel pumps. If the engine is running - the pump is pumping. Mechanical fuel pumps are pretty simple things - there are several ways a mechanical fuel pump can fail - the diaphragm in the pump can tear, the inlet or the outlet valve can stick or the spring in the pump can fail. Most of these failures will not cause the pump to completely stop pumping fuel - in some (many) cases the pump will still pump fuel - just not as much as it should be pumping (typically the fuel pump delivers a given amount of fuel every engine revolution) - but if the pump is failing - it may operate far better at higher engine speeds than at idle / low speed.

Remember - the carb has a float bowl that contains a small reservoir of gas - probably enough fuel to run the car at idle for the better part of a minute. Under "normal" conditions - there is enough fuel in the float bowl to get the car started, and to run for a seconds - while the pump starts to replenish the float bowl.

Your car may have stopped working in the garage - because the pump was failing, and at low speed it was hardly moving any fuel at all, and the car went through most (all) of the fuel in the float bowl as you brought it in and parked it in the garage.

 

Alright guys so I forgot to squirt some fuel in the carb to test that part, but I did get the fuel pump off, I also pulled the dipstick for the oil pan and it smelled like there was a hint of gas.

So as I was pulling the pump, the rubber hoses going from the steel fuel lines to the pump were bone dry inside, still malleable though but I think I should replace them anyways.
When I got the pump off some fuel was dripping from the inlet and outlet sides, and when I checked the actuation by hand, it barely got any fuel out the line that goes to the carb (I had to pull the pump with the line to the carb still attached to it), but when I turned it on it's side and actuated it again it started gushing, obviously from not having to work as hard.
As I was getting the fuel out I covered the inlet/return holes for the pump and for one of them it's VERY hard to actuate the pump, and then when covering the other one it's much easier to actuate the pump by hand. I'm pretty sure the way diaphragms work is that if either side is sealed it's not supposed to move at all, right?

It also appears that this pump is either original or just REALLY old. It has an "AC" stamped on the upper half, where the pump lever is housed, and the lever itself has like a dent on the tip's edge like it's caved in a bit.

Also, I still have everything else installed in the engine bay and did this removal without a lift or jacks, so I wasn't able to look directly inside the engine where the pump mounts to, to see how the rod looks, but I watched a video on replacing the pump and they said to use one of the longer bolts that mounts the pump, to hold the rod in place and not fall out. And, well, nothing fell out so I guess I did that right.

 

If it were my car id remove the fuel inlet hose to the pump with a pan under it and make sure you get a good steady flow of fuel since the filter sock in your tank could be plugged. the ac delco pump is the correct part for your car and the dent in the arm is also normal. I didnt read the whole thread but I assume you already checked the obvious stuff like the small fuel filter in the carb (if its a rochester qjet) before removing the fuel pump.

 

When you replace those hoses, be sure to use the proper "S" shape molded hose, or you'll get a pinch and bad fuel flow. The Corvette vendors carry it.

There are two parts to the fuel pump mount. The pump itself, and then a larger "panel" that will trap the pushrod. You should be able to feel the pushrod. Perhaps the bolt trick worked, and it stayed in position. The reason to take a look at it is to see if it is mushroomed, or has eaten the fuel pump cam.

But hopefully a new fuel pump solves your problem, and you don't have to worry about any of that!

I'd still pick up a set of low-approach-angle ramps, like these Race Ramps. When the car is running, it's a lot easier to get under the car to do this job.

 

Hey guys ummmmm
What's the fuel rate and psi of an original fuel pump?
I'm doing my shopping now and idk which replacement pump I need to get.
I've never done carb work either so idk what my carb would take

I looked around my old pump and found a stamp that says 090T41240

 

Try the part number SP1060MP

Good for small block Chevy engines from the 50’s to late 70’s

 

Alright guys, so I finally got the new pump installed, aaaaaaaaand no dice.
When the new pump came in I compared how it felt versus the old pump, and the old pump definitely felt like it was easier to manipulate by hand. The old pump also had an audible sound as if you were groaning while breathing in.

I installed the new pump. Put it in place with new gasket, set it with one screw, aligned the other, making sure the arm was up against the push rod (I could hear the distinct sound of the diaphragm moving), tightened the first screw of the pump to the engine, removed the screw holding the push rod in place, inserted and tightened the second screw to the pump.

I routed the fuel hoses so there were nice big bends, no kinks, the ends of the hoses go aaaaallll the way to the back of the in/out ends of the pump, and on the fuel line side they go about an inch deep.
Starter was cranking, even with less battery than full, and I heard no funny sounds from the driver seat.

After a few attempts, I removed the fuel line to the carburetor and there was no fuel coming out.
I also took the battery out to charge it for the next time I attempt to start the car.

What else could it be that's preventing fuel from flowing through the system? How would I know if a clog in the fuel tank is the culprit? I'm really trying to avoid removing the tank because I'm not exactly in an ideal location to be doing that.

 

Have you tried dribbling fuel into the carb (post #2) just to confirm that your problem is fuel flow?

Someone will correct me, but I think a stuck needle valve, or reversed check valve fuel filter (take it right out) will prevent fuel from flowing to the carb.