Not getting fuel to the carbs!

[bravemushi260z]

Hey guys I was so excited to get the 260z running today for the first time after rebuilding the carbs, changing all fluids, belts and radiator hoses. I tried getting it running and it was cranking but not starting. Sprayed some starter fluid into the carbs and started for a second then died. Took a look at the inside of the carb and realized it’s not getting any fuel. Pulled the line from the mechanical fuel pump to the fuel rail and no gas there either. Pulled out the mechanical fuel pump to make sure that the arm is in the right position, and it is. Tried to manually pump it and didn’t produce any gas. Chased back down to the plastic fuel filter and didn’t have any gas in it or gunk either. Went to the back to check the electric fuel pump, it’s definitely not working since I’m not hearing it turn on, but I was going to bypass it for now to see if I can get the car started. I was also wondering if the fuel filter in the electrical fuel pump was clogged. The weird thing is when I pulled off the electric fuel pump inlet from the gas tank, no gas came out? I have about 6 gallons of fresh gas in there, I can’t imagine it’s low on gas ? Not sure what’s causing this problem. By the way car runs good for a few seconds if I put gas straight into the carbs. Any help would be really appreciated! My last step will be checking the lines themselves, but after draining the gas tank I had no particles or any debris in there so they should be clean. Right now my problem is at the pumps, please let me know your thoughts !

[bravemushi260z]

Okay so after further inspection, Ive tried to vacuum (suck it out with my mouth) the fuel from the input side of the mechanical pump but no luck. I also realized that i dont have a fuel return line, and that it is capped off with a bolt (circled in blue below), will probably go buy a handheld vacuum pump tomorrow and try to see what i can do, but not sure where to go after that. 

carb side engine bay.jfif passenger sdie.jfif

[SteveJ]

If the wiring to the electric fuel pump is stock, you won't hear it running unless the engine is running. The electric pump does not run with the key in the START position, either.

If you disconnect the line between the tank and the electric fuel pump, gas should flow out of the tank. I suggest that you drain the tank (using the drain plug) and look for debris (rust, etc.) coming out.

You may need to drop the tank and boil it out & re-seal it. There are plenty of threads on here about that.

[bravemushi260z]

1 minute ago, SteveJ said:

If the wiring to the electric fuel pump is stock, you won't hear it running unless the engine is running. The electric pump does not run with the key in the START position, either.

If you disconnect the line between the tank and the electric fuel pump, gas should flow out of the tank. I suggest that you drain the tank (using the drain plug) and look for debris (rust, etc.) coming out.

You may need to drop the tank and boil it out & re-seal it. There are plenty of threads on here about that.

Hey Steve thanks for your response! So i already drained the tank before pulling off the carbs, and thankfully I didnt find any rust or debris in the tank. But it doesn't make sense that I didnt get gas coming out there when I pulled it off. Not sure where to go from here other than try and vacuum it out, my thoughts are there are air pockets that the mechanical pump cant get past, esepcially because i drained all of the gas out. 

 That's good to know about the pump, I thought it ran on its own. 

[SteveJ]

I looked at your photos. I don't know what the IPO (idiot previous owner) was doing to regulate fuel pressure to the carburetors. 

The fuel flow from the tank to the electric fuel pump is gravity feed only. If you don't have fuel when you pull the hose off the inlet side of the electric fuel pump, you won't ever get fuel through the line. Gas should be pouring out of the tank with the hose removed from the inlet side of the electric fuel pump unless you have the hose clamped off. Air pockets are not relevant in this case. Until you know you are getting fuel to the electric fuel pump, you will not be getting any fuel to the mechanical fuel pump.

In addition to starting fluid, you may need to prime the line between the mechanical fuel pump and the carburetors. That should get the float bowls filled in the carbs and keep the car running long enough to pump fuel through the rest of the fuel line.

So fill in the blanks:

1. How long have you owned the car?
2. Did it ever run since it was in your possession?
3. If it did, what happened to make it stop running?
4. What parts have you changed out?

[bravemushi260z]

4 minutes ago, SteveJ said:

I looked at your photos. I don't know what the IPO (idiot previous owner) was doing to regulate fuel pressure to the carburetors. 

The fuel flow from the tank to the electric fuel pump is gravity feed only. If you don't have fuel when you pull the hose off the inlet side of the electric fuel pump, you won't ever get fuel through the line. Gas should be pouring out of the tank with the hose removed from the inlet side of the electric fuel pump unless you have the hose clamped off. Air pockets are not relevant in this case. Until you know you are getting fuel to the electric fuel pump, you will not be getting any fuel to the mechanical fuel pump.

In addition to starting fluid, you may need to prime the line between the mechanical fuel pump and the carburetors. That should get the float bowls filled in the carbs and keep the car running long enough to pump fuel through the rest of the fuel line.

So fill in the blanks:

1. How long have you owned the car?
2. Did it ever run since it was in your possession?
3. If it did, what happened to make it stop running?
4. What parts have you changed out?

I don't know what he was doing either, the bolt there isn't even tied down its completely loose. 

I understand about the electric fuel pump, I'll direct my focus to it tomorrow morning when I get back out to the car. Im bringing my handheld vacuum pump and hooking it up to try and suck out anything that is stuck there. 

I will bring a funnel and prime that line to get the the fuel pump going, thank you so much. 

1. Ive had the  car about a month but finally got to it a few days ago

2. Haven't had her run yet, I've changed radiator hoses, belt, rebuilt the carbs, drained gas(came out clear) , oil change, changed coolant, new battery, new spark plugs and wires. Nothing with the fuel system. I also added seafoam to the gas I added just incase there was anything in the lines

[Patcon]

Has the fuel tank been lined or restored? Sometimes tank liner can block up the lines. I would take a little piece of SS aircraft cable and route it into the tank line to make sure it's clear. I have even chucked long pieces up in a cordless drill for stopped up hardlines

[bravemushi260z]

43 minutes ago, Patcon said:

Has the fuel tank been lined or restored? Sometimes tank liner can block up the lines. I would take a little piece of SS aircraft cable and route it into the tank line to make sure it's clear. I have even chucked long pieces up in a cordless drill for stopped up hardlines

As far as I know, it hasn't been but I will be tying vacuuming the lines, blowing air though them, and the cable tomorrow. Hopefully I can figure it out and get this running!

[siteunseen]

Weedeater cord works too. That should be an easy figure out type thing but those can take a sharp turn.

In and out of the tank. You can get a low psi pump from a chain parts store for $20 and straight wire it WITH CLIPS for quick disconnect from the battery. Have a hose pipe or fire extinguisher close by. Best of luck.

[bravemushi260z]

21 hours ago, SteveJ said:

I looked at your photos. I don't know what the IPO (idiot previous owner) was doing to regulate fuel pressure to the carburetors. 

The fuel flow from the tank to the electric fuel pump is gravity feed only. If you don't have fuel when you pull the hose off the inlet side of the electric fuel pump, you won't ever get fuel through the line. Gas should be pouring out of the tank with the hose removed from the inlet side of the electric fuel pump unless you have the hose clamped off. Air pockets are not relevant in this case. Until you know you are getting fuel to the electric fuel pump, you will not be getting any fuel to the mechanical fuel pump.

In addition to starting fluid, you may need to prime the line between the mechanical fuel pump and the carburetors. That should get the float bowls filled in the carbs and keep the car running long enough to pump fuel through the rest of the fuel line.

So fill in the blanks:

1. How long have you owned the car?
2. Did it ever run since it was in your possession?
3. If it did, what happened to make it stop running?
4. What parts have you changed out?

Okay so I primed the fuel lines, starting fluid and cleared the line coming out of the gas tank! I’m getting fuel now up to the mechanical pump which I see in the fuel filter but still not getting enough to the carbs, I know I’m getting some because the car will sometimes just barely start and then die. I think the mechanical pump may be bad. Just ordered one that should be here at the end of the day!

[bravemushi260z]

Got it running!

[kunzma]

Having the same issue after replacing the same items.  New mechanical fuel pump still hasn't fixed the problem.  What worked for you?

Edited May 1, 2021 by kunzma