Carburetor fuel hose feed connection?

petex19

petex19

True Classic
I've had my X for 32years and my fuel hose has always came from the bottom of the tank to the fuel pump, fuel filter, pressure regulator and then the carbs.

I was just scrolling through many pictures of other members engine bays and they all run the fuel hose to the carbs from the top of the fuel tank. Is that the correct way?
 
Your car must have an FI tank. The carb tanks have no provision for fuel in or out. The tubes are integral to the carb specific fuel sender unit that bolts onto the top of the tank. So in short, yes, the stock carb fuel lines connect at the top.


FI sender unit is pictures above the carb unit. Note the sender itself is mounted on the output tube on the carb unit, the return is the rubber line. The FI unit only uses the tube to mount the sender, it does not extend low into the tank.
IM002961.JPG


carb tank bottom
carb_tank_2.JPG


FI tank bottom
tank_swap_2.JPG
 
Last edited:
JimD said:
Your car must have an FI tank. The carb tanks have no provision for fuel in or out. The tubes are integral to the carb specific fuel sender unit that bolts onto the top of the tank. So in short, yes, the stock carb fuel lines connect at the top.
Click to expand...
Yes '84X was a F.I car originally. So it's connected correctly from the bottom?
 
petex19 said:
Yes '84X was a F.I car originally. So it's connected correctly from the bottom?
Click to expand...
It depends on the pump you are using. If you are using the original high pressure FI pump, then "from the bottom" is appropriate. Those pumps wanted more head pressure from the fuel in the tank and pushed the fuel more than it pulled. The FI pump pushes at much higher PSI. IIRC its around 50 PSI? Maybe?? And the FI regulator holds the system to 30-ish PSI.

The mechanical pump for the carbs had the pulling power to bring the fuel up from the bottom of the tank, but then only put out about 4-5PSI to the carb.
 
JimD said:
It depends on the pump you are using. If you are using the original high pressure FI pump, then "from the bottom" is appropriate. Those pumps wanted more head pressure from the fuel in the tank and pushed the fuel more than it pulled. The FI pump pushes at much higher PSI. IIRC its around 50 PSI? Maybe?? And the FI regulator holds the system to 30-ish PSI.

The mechanical pump for the carbs had the pulling power to bring the fuel up from the bottom of the tank, but then only put out about 4-5PSI to the carb.
Click to expand...
My fuel pump is a Holley fuel pump with 7psi max. My fuel pressure regulator maintains 3.5psi for my carbs. I have never had fuel pressure issues. I was just curious as all the pictures I found draw fuel from the top of the tank. I understand now.
 
Last edited:
JimD said:
Your car must have an FI tank. The carb tanks have no provision for fuel in or out. The tubes are integral to the carb specific fuel sender unit that bolts onto the top of the tank. So in short, yes, the stock carb fuel lines connect at the top.


FI sender unit is pictures above the carb unit. Note the sender itself is mounted on the output tube on the carb unit, the return is the rubber line. The FI unit only uses the tube to mount the sender, it does not extend low into the tank.
View attachment 83833

carb tank bottom
View attachment 83835

FI tank bottom
View attachment 83834
Click to expand...
Now I have to look at the bottom of my fuel tank. I'm almost positive that I only have the one output connection. What is the second one for?
 
petex19 said:
Now I have to look at the bottom of my fuel tank. I'm almost positive that I only have the one output connection. What is the second one for?
Click to expand...
You do have only one output connection, the second is for the return line. Maybe you don't use the return in your carb setup?
 
JimD said:
You do have only one output connection, the second is for the return line. Maybe you don't use the return in your carb setup?
Click to expand...
I don't use a return so would that second one be plugged off? I really need to look at my setup under the car.
 
You must log in or register to reply here.
Back
Top