No fuel to carb

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dstan

dstan

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Put a fresh built 383 in my truck and couldn't get the efi happy. I got tired of messing with it and swapped it back to a carb. After installing new fuel lines, filter, and putting in a pushrod to actuate the mechanical pump I'm not getting any fuel to the carb. I primed the fuel line before connecting it the pump. I'm not feeling any pressure build in the line after the pump (disconnected from carb with my finger on the end). Any suggestions on getting this running? I don't really want to drop another $150 on a fuel pump, but if coconscious is that the pump is bad I'll do it.
 
Is the tank venting properly? The tank needs to breath in order for fuel to flow. Take the fill cap off and see if you get flow, that will tell you if its not venting.
 
dano said:
Is the tank venting properly? The tank needs to breath in order for fuel to flow. Take the fill cap off and see if you get flow, that will tell you if its not venting.
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No difference with the cap off.
 
Your fuel pickup sock in the tank could be plugged. Try clearing it using compressed air to back flush it. 65'
 
Plymouth 65 said:
Your fuel pickup sock in the tank could be plugged. Try clearing it using compressed air to back flush it. 65'
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I'll give it a try when the rain lets up. It had no problem drenching me in fuel when I unhooked the high pressure pump though. lol
 
dstan said:
Put a fresh built 383 in my truck and couldn't get the efi happy. I got tired of messing with it and swapped it back to a carb. After installing new fuel lines, filter, and putting in a pushrod to actuate the mechanical pump I'm not getting any fuel to the carb. I primed the fuel line before connecting it the pump. I'm not feeling any pressure build in the line after the pump (disconnected from carb with my finger on the end). Any suggestions on getting this running? I don't really want to drop another $150 on a fuel pump, but if coconscious is that the pump is bad I'll do it.
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Hey dstan,

If you can, eliminate the fuel line from the tank and the tank itself by using a piece of fuel hose into a fuel can and then into the inlet of the fuel pump. if still no flow, pump possibly bad ,or pushrod not engaging lever on pump properly.
 
AAndrews said:
Hey dstan,

If you can, eliminate the fuel line from the tank and the tank itself by using a piece of fuel hose into a fuel can and then into the inlet of the fuel pump. if still no flow, pump possibly bad ,or pushrod not engaging lever on pump properly.
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I'll pick up a can on 93 tomorrow and give it a try.
 
I guess if there is a problem with fuel flow from the tank that would explain why the efi leaned out under load as well.
 
dstan said:
I guess if there is a problem with fuel flow from the tank that would explain why the efi leaned out under load as well.
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Possibly, and EFI is going to require a higher stable psi to operate correctly. That's usually why these systems use electric fuel pumps.
 
AAndrews said:
Possibly, and EFI is going to require a higher stable psi to operate correctly. That's usually why these systems use electric fuel pumps.
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I was using a high pressure pump for the efi. I rerouted the fuel lines to bypass it when the carb went back on.
 
Is the pushrod moving when you crank the motor? Put the fuel pump in loosely and watch it to see of it moves when you bump the motor. Pumps can be bad. It's a suction so if there are any holes in the line to the tank it will pull air instead of heavier fuel.
 
You can continue to use your high pressure pump with a low pressure regulator to carb and a return line.
 
pishta said:
Is the pushrod moving when you crank the motor? Put the fuel pump in loosely and watch it to see of it moves when you bump the motor. Pumps can be bad. It's a suction so if there are any holes in the line to the tank it will pull air instead of heavier fuel.
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All lines are new, so is the cam and the fuel pump pushrod. I'll try loosening the bolts after I try running it out of a can (hard to get to them)
 
In and out ports of pump labeled? Hey. I've had dumber discoveries....
 
dstan said:
I was using a high pressure pump for the efi. I rerouted the fuel lines to bypass it when the carb went back on.
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Should be interesting result when you bypass the tank tomorrow . It may have been your problem all along.
 
No rollers for Bs unless it's aftermarket. No efi offered. B/RB pump eccentrics were integral to the cam blanks between the distributor gear and #1 cam lobe.
 
dstan said:
All lines are new, so is the cam and the fuel pump pushrod. I'll try loosening the bolts after I try running it out of a can (hard to get to them)
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This is interesting as well. You said you put in new fuel lines .Check to see if they are bent or crushed anywhere. Your truck probably ran ok before you installed the EFI and new fuel lines. You tried an electric fuel pump which eliminates the new cam and push rod as a problem, then you went back to the mechanical pump and still had a fuel delivery problem. I'm thinking tank lines or blocked line out from the sending unit.
 
AAndrews said:
This is interesting as well. You said you put in new fuel lines .Check to see if they are bent or crushed anywhere. Your truck probably ran ok before you installed the EFI and new fuel lines. You tried an electric fuel pump which eliminates the new cam and push rod as a problem, then you went back to the mechanical pump and still had a fuel delivery problem. I'm thinking tank lines or blocked line out from the sending unit.
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The truck had a 440 that spun 4 bearings. I built a 383 and put the efi in when the 383 went in. It was never ran with a carb, but the mechanical pump is from the 440.
 
dstan said:
That was the first thing I checked. Lol
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You can see if the pump moves when the engine is turned, but let tell you a little trick I use.
With the pump bolts 3 or so turns loose turn the motor until the pump body raises up because the pushrod pushed down on the lever of the pump inside the motor.
Then push down on the pump body with your hand a few times.
It makes the pump work if it’s a working pump.
That said, with the info given in this thread it sounds like a bad pump to me.

I also physically blow breath (not compressed air) through the line from the pump to the tank.
If I hear bubbles, good.
If I don’t hear bubbles I know the pump can’t reach fuel for some reason.
But you said the efi pump got fuel, so that says it’s a bad pump. :D
 
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dstan said:
The truck had a 440 that spun 4 bearings. I built a 383 and put the efi in when the 383 went in. It was never ran with a carb, but the mechanical pump is from the 440.
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Well dstan,

There's enough diagnostic info here to keep you busy tomorrow. Should be able to find the problem quickly with the suggestions given you. Good luck with it. Let us know how you make out!
 
I rerouted the fuel line today, because it had a spot that went up a little higher than the tank, and blew back through the line with not resistance. Ran a line into a can and it pumped gas to the carb no problem. Hooked the line to the tank back up and the carb being filled kept it running long enough to pull gas from the tank. Now I just need to recharge the battery and get the idle set correctly. And change clothes because I was covered in gas and may have caught on fire for a little bit... oops. Thank you everyone for your advice.
 
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