5.9 l runs out of fuel overnight, won't prime

mopar440

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1989 grand Wagoner 5.9

Just got this in, thought I'd pick " the brain" before I dig in

Issue: if you prime the carb, it will run all day, start fine etc

It sits overnight, and no matter what you do or crank, won't prime the carb. Once you hit it with starting fluid, it will prime, and go all day

1. 2 rebuilt carbs, 2 new fuel pumps, filters, new gas tank

I'm thinking these have a pushrod on the pump? I haven't dug into it yet
 
How's the fuel line? I once had a car that had pin-hole rust in the fuel line that was not enough to drip or cause a strong smell to make you think fuel leak... but caused all kinds of aggravation allowing air seepage.

Found it by seeing a wet spot on the line, but no dripping or strong fuel odour.
 
How many miles on it? The 5.9 uses an eccentric on the front of the camshaft to operate the fuel pump. You might have to open up the front of the engine to inspect, might also be time for a timing chain.
 
How's the fuel line? I once had a car that had pin-hole rust in the fuel line that was not enough to drip or cause a strong smell to make you think fuel leak... but caused all kinds of aggravation allowing air seepage.

Found it by seeing a wet spot on the line, but no dripping or strong fuel odour.
I'm gonna inspect that also, disconnected line and cranked. I've got fuel, gotta dig out my gauge
 
How many miles on it? The 5.9 uses an eccentric on the front of the camshaft to operate the fuel pump. You might have to open up the front of the engine to inspect, might also be time for a timing chain.
I'm a bigblock guy, is it common for those to wear and cause issues? Looks like 113,000
 
Got my gauge hooked up, really bounces. Not very accurate under 10, but it's looking like 2-5 ish. Low pressure

Looked at fuel lines, most rubber is new, and the lines look suprisingly clean.

I wonder if a hole in a pick-up line could do that?
 
How's the fuel line? I once had a car that had pin-hole rust in the fuel line that was not enough to drip or cause a strong smell to make you think fuel leak... but caused all kinds of aggravation allowing air seepage.

Found it by seeing a wet spot on the line, but no dripping or strong fuel odour.
Not familiar with those but fuel line would be my guess too. Sucking air from somewhere.
 
For a mechanical pump 5 psi is about right. Bouncing reading is not a good sign. Try running a fuel line into a gas can overnight to see if the pump is not holding the pressure. At 113,000 miles the chain is probably stretched, but the factory tensioner should be taking most of the slop out of it.
 
For a mechanical pump 5 psi is about right. Bouncing reading is not a good sign. Try running a fuel line into a gas can overnight to see if the pump is not holding the pressure. At 113,000 miles the chain is probably stretched, but the factory tensioner should be taking most of the slop out of it.
I was thinking of pulling a vacuum on the main fuel line, looking for a leak

Where you talking about pulling the line off and putting in a gas can? Off the carb? I wonder if the problem could be drying out the carb overnight?
 
They also have the filter on the pump out put, most I've seen are on the input line
 
The fuel filter should be between the pump and carb. I would disconnect the line from the tank to the pump, and install the line and gas can there. get the car running, and then put a dry container under the hose and let it sit overnight. If the container is wet in the morning the fuel is draining out of the pump.
 
I cranked on it again, no filter, and the needle barely moved. It started

Running, it doesn't even make it out of this low pressure box. I'm going to get a carb only gauge

IMG_20200620_132520795.jpg
 
Weird, hooked up new gauge, no start/no fuel...

Anyway to check that fuel pump eccentric?
 
The only way is to remove the timing cover, I think that is your problem. That is why I want you to hook up the outside fuel line. I have also seen the filter sock in the tank go bad, and make the car act like it has run out of fuel.
 
The only way is to remove the timing cover, I think that is your problem. That is why I want you to hook up the outside fuel line. I have also seen the filter sock in the tank go bad, and make the car act like it has run out of fuel.
Yeah, that's my next step. If ecentric is worn, probably going with a electric pump
 
Just cut to the chase and install a 7psi electric pump. As the fuel pump pipe (frame side) is usually lower than the tank's mounting level, I suspect there should be fuel THERE without the engine running? If you use shop air pressure to "blow out" the supply lines, you'll probably pressure-off the sock filter in the tank, possibly? It's alleged main function is to decrease moisture that might get from the tank into the fuel lines, pump, and carb? As a pre-filter of sorts.

The mechanical fuel pump has two check valves. One to allow fuel in, then shuts when the outlet valve opens under pressure. The inlet valve should hold fuel in the pump body until it might evaporate out, I believe. Any fuel in the motor oil?

Has somebody already been into the front cover area of the motor? Which might explain the issue with the eccentric either failed or not being there? Just curious . . . Which is why my '80 Newport 360 2bbl ended up with an electric pump, after a timing chain replacement. Work done by a friend's independent mechanic shop.

Just some thoughts,
CBODY67
 
Just cut to the chase and install a 7psi electric pump. As the fuel pump pipe (frame side) is usually lower than the tank's mounting level, I suspect there should be fuel THERE without the engine running? If you use shop air pressure to "blow out" the supply lines, you'll probably pressure-off the sock filter in the tank, possibly? It's alleged main function is to decrease moisture that might get from the tank into the fuel lines, pump, and carb? As a pre-filter of sorts.

The mechanical fuel pump has two check valves. One to allow fuel in, then shuts when the outlet valve opens under pressure. The inlet valve should hold fuel in the pump body until it might evaporate out, I believe. Any fuel in the motor oil?

Has somebody already been into the front cover area of the motor? Which might explain the issue with the eccentric either failed or not being there? Just curious . . . Which is why my '80 Newport 360 2bbl ended up with an electric pump, after a timing chain replacement. Work done by a friend's independent mechanic shop.

Just some thoughts,
CBODY67
Electric is the only way I think they will go, they like stock tho

No fuel in oil, and cover doesn't look disturbed

I like to figure it out for the learning experience
 
On a 360, goes the pump mount with the outlet "up" this one is. All my BB Mount outlet "down"
 
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