Went out for a drive yesterday and almost had to call a tow truck to get home. I drove for about 45 minutes, and stopped at a store for about half an hour, the car cranked a little bit longer than usual before getting started. About a minute into the return home the engine sputtered and died. I pumped the gas a few times tried to restart it and it fired up again. I had one more stop to make about a mile from home, so I took a chance. Car was shut down for about 15 minutes. The same thing happened again. This time I had no joy getting it restarted. I pulled the air cleaner off and pumped the gas a few times. No fuel was making it into the carburetor. I recently replaced the fuel pump and filter as well as all the hoses connected to it. I checked for kinks and then started disconnecting the hoses looking for a blockage, and it seemed that fuel was getting to the filter but not through it. At that point I thought maybe it was just residual fuel and the fuel pump wasn't pumping anymore, or that there was a blockage in the filter. I cranked the engine over to see if fuel was making it through the filter, and sure enough it was. Reconnected it to the carburetor and suddenly I had fuel in the carburetor again. As I'm writing this I realized I did not look into the gas tank to see if the outlet sock was clogged or had debris around it. The other three possibilities are bad fuel pump, clogged filter, or something going on in the carburetor itself. As I was inspecting things again when I got home, I realized there was a small split in the rubber hose right at the carburetor connection. I'm not sure if that was there before the problem started or if I created it when I was moving hoses around. Also not sure how that would have caused the issue without squirting fuel all over the engine bay.

The car is a 1972 with a non original 383 stroker. Brawler 670 carburetor on a Victor Jr intake and an replacement OEM style fuel pump.

I'm looking for any feedback before I start replacing parts.

 

You are a wise man.
Because you ordered & installed the mandatory, preformed, "S" fuel hose at the pump.

 

'I used the correct s hose.


These aren't the droids we're looking for..

 

So the Brawler should have sight glasses on both bowls. Did you look at the fuel level when this happened? I understand you opened the throttle by hand to check the accelerator squirt.

 

Sounds like a vapor lock type of issue.

 

Thanks for the feedback.

I am not sure what vapor lock means. Can you explain?

Some more information... Prior to this situation, the engine had been slow to return to idle from higher rpm. So when I would push in the clutch and come to a stop it would take 10-20 seconds for the idle to come down. Or it would come down if I tapped the gas pedal a little. It was not a sticky cable, so I used some sprayed carb cleaner and it seemed to fix the idle issue. DId I cause this other issue and create a blockage somehow?

 

If you got the time i had same issue here..
https://www.corvetteforum.com/forums...e-on-road.html

first verify flow and pressure of fuel pump, then verify rest of fuel system.

 

What happens is the carburetor and fuel line heats up and the fuel begins to boil. When you shut off the car the fuel in the fuel line becomes vapor and pushes back on the fuel in the line creating a bubble the fuel can't push past at 4 or 6 psi. That's why it doesn't happen in fuel injection at 60 psi. As for the slow return to idle, the heated fuel creates a pressure in the fuel bowl will push the fuel through the carburetor and into the engine.

If you add in a 1/4 inch phenolic spacers or a heat shield it helps a lot. Shielding the fuel lines help as well. If you have enough room thicker spacers are better for heat and more torque and hp, not much but it helps

 

Actually, Vapor Lock is just that. The fuel due to heat, turns to vapor. A mechanical fuel pump can not, will not, pump vapor. (It MUST be in liquid form)
Thereby "locking" the fuel line from pump to carb. The fuel bowls will be empty.

Another issue on hot engines is Fuel Percolation. That expansion of fuel in the bowls will actually percolate out of the bowl vents. Often spilling into the venturi and eventually flooding the engine.
These are two different scenarios, two different terms. But both can happen with excessive heat.

As far as a slow return to idle RPMs. That is usually just plain weak return springs.
Sometimes the ends of the spring (hooks) have been relocated at the throttle or somewhere on the Intake. Then the leverage is lacking to snap the throttle closed.
And sometimes it's just a bunch of crud bound up inside the cables sheath from firewall to the pedal. Clean & lube will fix that.

 

i would think the pump still pumps with a return line? eliminating vapor lock? maybe try different gas? no ethanol?

 

Sorry you are having troubles.
Call me if you want to chat.

First I would pull a line off the carb and verify fuel pump flow ~30 secs for 1 pt
If not pull the S-hose and check for flow from the tank ~ gravity
Next I would check psi - you will need a 15 or 30 psi gauge, not the 150psi supplied with most fuel testers these days.
Can be hooked up with rubber hoses and clamps if you do not drive it that way.
Should be 4-6psi into carb.

Fuel pumps are very suspect these days, even brand new ones.

 

Thanks Leigh.

I am pretty sure the pump is (was) ok. I ran the car in the driveway for 1/2 hour, shut it down, then restarted 1/2 hour later and it was fine. I originally thought that the issue had to due with using carb cleaner to fix the slow return to idle. Then I remembered...I had a leak in the pump supply fitting a few weeks ago and rerouted the rubber line a little closer to the engine. I think this was causing a vapor lock.

In any case I went to work on the fuel line yesterday and cracked the bottom of the pump. I was trying to tighten the L angle fitting (without removing the pump) and it bent the bottom of the pump and cracked.

I would rather get a better pump, but am having a hard time figuring out what is available, and will bolt on without too much customization. As it is, it seems that there are 2 more connections than necessary with the OEM style pumps - which are just more opportunities for leaks. - the stainless fuel line needs another step down fitting to thread into the L angle fitting, which threads into the pump.

Scott

 

You have a 72 so the pump from the factory would have 3 connections, inlet, outlet and return line. Hopefully you are using the return line.

 

Thanks. I am using all of the correct hoses and fittings. The S hose and return line, the hard line, and the L angle fitting. The issue is that the hard line threading is a little bit larger than the either the L angle or the pump female thread. I have an adapter to step the threads down from the hard line to the L angle fitting. But it's a taper fit instead of a flare fit, so I had to tighten the heck out of it to keep it from dripping.

Scott

 

Why not the factory hard line from pump to carburetor. You can modify the carburetor end.

 

The issue is with the a replacement OEM Hardline

 

Is this the pump you are using
Pump

 

Is this the fitting
Fitting

 

I used this fitting
https://www.summitracing.com/parts/SBC-9178K
and this pump
https://www.autozone.com/external-en...B&gclsrc=aw.ds


I just realized that the fuel line I have is for a 1976 to 1980. Not sure if the fittings are different, oir just the shape of the bends.