ZCar Forum banner

Status
Not open for further replies.
1 - 3 of 3 Posts

·
Registered
Joined
·
107,695 Posts
Discussion Starter #1
i just bought a 1977 280z. the fuel gauge does'nt work (been tracing that) so i used the trip odometer to tell when to fill up. my problem is, the book says it holds like 12 gallons or something, i can't remember. i ran it out of gas the other day, and when i got it to a gas station, it only took 8 gallons to fill!!!! why is my car hoarding 4 gallons of fuel from me? also the fuel pump has been making a little more noise than usual, do these things go out all at once, or is it telling me it's time for relacement? if i do have to buy a new one, i'm going holley or some other aftermarket pump cause i'm planning on nitrous later, so what psi do i need minimum? Thanks for any help, chris
 

·
Registered
Joined
·
1,760 Posts
If your fuel gauge dosent work, try to remove the sending unit from the tank. There should be a access hole cover in the rear deck area, behind the passener tail light. Remove the two screws, lift cover and you will see where the sending unit goes into the tank. Use a flat tip screwdriver and a hammer to loosen the retaining ring. Once loose, unplug the unit and remove from tank.
There are 3 wires on the sending unit connector (black-ground, yellow-to gauge, and yellow w/ blue stripe-to fuse box) Check the 4th fuse (on the row towards the firewall) and see if it is good.
Next, try to gound the yellow wire. (do not ground the yellow w/ blue stripe!), look at the gauge in the dash... does the gauge go to full? If so all is good. If not, make sure you have continuinty in the yellow wire coming from the tank area to the connector to the gauge. If that is good, then replace gauge.
To test the sending unit, hook the unit up to the wiring connector and place a 32 ohm resistor between the yellow wire and ground. Look at the gauge. It should read half level. If not, replace the sending unit.

The fuel tank holds 17 1/8 gals.

Make sure the fuel lines are not reversed on the tank. There are two fuel lines that leave the tank on the passenger side. The top one goes to the fuel pump inlet and the bottom line is the fuel return. Be sure to trace these line under the car and make sure they go to the proper places on the motor. The line that leaves the fuel pump should go to the fuel filter and leave the fuel filter and go to the top line on the fuel rail.
The bottom line on the fuel rail is the return line.

Your tank could have a busted pick up tube inside...

Fuel pressure that leaves the fuel pump is around 80 psi, but by the time it leave the fuel filter it is around 36 .psi
 

·
Registered
Joined
·
1,760 Posts
If your fuel gauge dosent work, try to remove the sending unit from the tank. There should be a access hole cover in the rear deck area, behind the passener tail light. Remove the two screws, lift cover and you will see where the sending unit goes into the tank. Use a flat tip screwdriver and a hammer to loosen the retaining ring. Once loose, unplug the unit and remove from tank.
There are 3 wires on the sending unit connector (black-ground, yellow-to gauge, and yellow w/ blue stripe-to fuse box) Check the 4th fuse (on the row towards the firewall) and see if it is good.
Next, try to gound the yellow wire. (do not ground the yellow w/ blue stripe!), look at the gauge in the dash... does the gauge go to full? If so all is good. If not, make sure you have continuinty in the yellow wire coming from the tank area to the connector to the gauge. If that is good, then replace gauge.
To test the sending unit, hook the unit up to the wiring connector and place a 32 ohm resistor between the yellow wire and ground. Look at the gauge. It should read half level. If not, replace the sending unit.

The fuel tank holds 17 1/8 gals.

Make sure the fuel lines are not reversed on the tank. There are two fuel lines that leave the tank on the passenger side. The top one goes to the fuel pump inlet and the bottom line is the fuel return. Be sure to trace these line under the car and make sure they go to the proper places on the motor. The line that leaves the fuel pump should go to the fuel filter and leave the fuel filter and go to the top line on the fuel rail.
The bottom line on the fuel rail is the return line.

Your tank could have a busted pick up tube inside...

Fuel pressure that leaves the fuel pump is around 80 psi, but by the time it leave the fuel filter it is around 36 .psi
 
1 - 3 of 3 Posts
Status
Not open for further replies.
Top