Car won't start sometimes..

[BlueDream]

Lately when I take the Dart out for a drive and park it it doesn't want to start when I get back in. The fuel filter will be full of gas when I park it but when I come back it'll be empty and when the car is running it doesn't always fill up the fuel filter. Could it be an air leak in the system somewhere? Right after the engine swap I could leave the car overnight and the filter would be full the next day but now it's empty after 15 minutes. I've replaced the pump and the filter and the hose is all new as are the clamps. Anybody know how to fix this? thanks

 

[67Dart273]

The fact is modern ethanol fuels raise what is called the RVP. Meaning, they vapor lock/ boil "worser."

Best things I did for my 67..........

Finally converted it to EFI

But BEFORE THAT

Abandoned mechanical pump, installed rear mount electric pump

Constructed vapor return system using an orifice fuel filter, AKA Wix 33040 / 33041

Added carb heat spacer. I used a 3/8" I think. Bought locally at O'Reallys

The vapor return systems were first used in the factory 440 and hemi cars, not sure just when, sometime in the 60's. First one I ever saw or had was on my 70 V code RR. IT WORKED

"The usual stuff"

Pay attention to fuel line routing, consider new hi tech sleeve insulation for the purpose

Some carbs, EG Ed AFB, are worse because the fuel bowls are in contact with the hot manifold surface

Consider blocking the carb heat crossover

Make sure the engine isn't overheating. Can the engine temp be improved?

It's ALWAYS possible you just plain have something wrong in the fuel system, IE plugged vent, weak fuel pump, pinhole leaks in the supply tube, or whatever. How old? again? are these girls?

 

[Brenda65]

Lately when I take the Dart out for a drive and park it it doesn't want to start when I get back in. The fuel filter will be full of gas when I park it but when I come back it'll be empty and when the car is running it doesn't always fill up the fuel filter. Could it be an air leak in the system somewhere? Right after the engine swap I could leave the car overnight and the filter would be full the next day but now it's empty after 15 minutes. I've replaced the pump and the filter and the hose is all new as are the clamps. Anybody know how to fix this? thanks

Sent you a PM

 

[BlueDream]

The fact is modern ethanol fuels raise what is called the RVP. Meaning, they vapor lock/ boil "worser."

Best things I did for my 67..........

Finally converted it to EFI

But BEFORE THAT

Abandoned mechanical pump, installed rear mount electric pump

Constructed vapor return system using an orifice fuel filter, AKA Wix 33040 / 33041

Added carb heat spacer. I used a 3/8" I think. Bought locally at O'Reallys

The vapor return systems were first used in the factory 440 and hemi cars, not sure just when, sometime in the 60's. First one I ever saw or had was on my 70 V code RR. IT WORKED

"The usual stuff"

Pay attention to fuel line routing, consider new hi tech sleeve insulation for the purpose

Some carbs, EG Ed AFB, are worse because the fuel bowls are in contact with the hot manifold surface

Consider blocking the carb heat crossover

Make sure the engine isn't overheating. Can the engine temp be improved?

It's ALWAYS possible you just plain have something wrong in the fuel system, IE plugged vent, weak fuel pump, pinhole leaks in the supply tube, or whatever. How old? again? are these girls?

I run non ethanol fuel and the fuel pump is a week old. It's an Edelbrock 1405 so I think i'm going to try a 160 degree thermostat and a carb spacer of some sort to see if that helps. The only line I haven't checked is the rubber line going from the tank to the hard line, if it was to leak there would it cause my fuel filter to drain down when the car is off? As far as I know it's original and ancient but it looked good when I pulled the tank in June..

 

[AJ/FormS]

Update? Problem solved, or.....?.If the connecting hose at the back is"cracked", the mechanical pump will begin drawing air with the fuel,eventually filling the upstream line with air. At low rpm it might work Ok, but as rpms rise it may start pulling more air than fuel. Also, hoses sometimes fail from the inside out.The pump only likes to pump liquid.Within a short time the fuel bowl(s) go dry, if running. At shutdown, there may still be fuel remaining between the carb and the pump.If the valves in the pump are not 100% some fuel may drain back towards the tank, partially draining the filter. I have also seen Gear clamps not work properly on the suction side, esp when the hose and pipe are mismatched. I try to reuse the spring clamps. But if going to gearclamps I usually put 2 clamps on;back-to-back and rotated 180* Also, If there is a restriction on the suction side of the pump, it will start to pull bubbles out of the fuel eventually starving itself. The restriction could be a failed rubber line, a pinched hardline,internal rust or a clogged in-tank sock. I have seen them all, sometimes on the same car.