Toyota Celica/Supra 1971-1985 Repair Guide

Mechanical Fuel Pump

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All 1971-74 and 1980-83 Celicas (carbureted) are equipped with a mechanically operated fuel pump of diaphragm construction (1980-83 cars use two different types of pump). A separate fuel filter is incorporated into the fuel line. See General Information & Maintenance for its required service. On 1971-74 models, the fuel pump is located on the right side of the engine block. On 1980-83 models, it is located on the right side of the cylinder head.

REMOVAL & INSTALLATION



1971-74 Models

See Figures 1 and 2



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Fig. Fig. 1: The fuel pump on 1971-72 models can be disassembled for repair



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Fig. Fig. 2: The fuel pump on the 1973-74 models is slightly different from that on the earlier models

  1. Disconnect the negative battery cable.
  2.  
  3. Disconnect and plug both of the fuel lines from the fuel pump.
  4.  
  5. Unscrew and remove the two fuel pump mounting bolts.
  6.  
  7. Withdraw the fuel pump assembly from the engine block.
  8.  
  9. Installation is in the reverse order of removal.
  10.  

Always use a new gasket when installing the fuel pump.

  1. Start the engine and check the pump for any leaks.
  2.  

1980-83 Models

See Figure 3



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Fig. Fig. 3: The mechanical fuel pump was reintroduced in the 1980-83 models, but was not repairable

  1. Disconnect the negative battery cable.
  2.  
  3. Drain the radiator coolant.
  4.  

When draining the radiator, use a clean container so that the coolant may be reused.

  1. Disconnect the upper radiator hose and wire it out of the way.
  2.  
  3. Disconnect and plug the three fuel lines from the fuel pump.
  4.  
  5. Unscrew the two fuel pump retaining bolts and remove the fuel pump and gasket.
  6.  
  7. Installation is in the reverse order of removal.
  8.  

Always use a new gasket when installing the fuel pump.

  1. Start the engine and check for any leaks.
  2.  

TESTING



Fuel pumps should always be tested on the vehicle. The larger line between the pump and tank is the suction side of the system and the smaller line, between the pump and carburetor or fuel injection pump is the pressure side. A leak in the pressure side would be apparent because of dripping fuel. A leak in the suction side is usually only apparent because of a reduced volume of fuel delivered to the pressure side.

  1. Tighten any loose line connections and look for any kinks or restrictions.
  2.  
  3. Disconnect the fuel line at the carburetor or fuel injection pump. Disconnect the distributor-to-coil primary wire (gasoline engines). Place a container at the end of the fuel line and crank the engine a few revolutions. If little or no fuel flows from the line, either the fuel pump is inoperative or the line is plugged. Blow through the lines with compressed air and try the test again. Reconnect the line.
  4.  
  5. If fuel flows in good volume, check the fuel pump pressure to be sure (pressure tests are possible only on gasoline engines).
  6.  
  7. Attach a pressure gauge to the pressure side of the fuel line. On cars equipped with a vapor return system, squeeze off the return hose.
  8.  
  9. Run the engine at idle and note the reading on the gauge. Stop the engine and compare the reading with the specifications listed in the "Tune-Up Specifications" chart. If the pump is operating properly, the pressure will be as specified and will be constant at idle speed. If pressure varies sporadically or is too high or low, the pump should be replaced.
  10.  
  11. Remove the pressure gauge.
  12.  

The following flow test can also be performed:

  1. Disconnect the fuel line from the carburetor or the fuel injection pump. Run the fuel line into a suitable measuring container.
  2.  
  3. Run the engine at idle until there is one pint of fuel in the container. One pint should be pumped in 30 seconds or less.
  4.  
  5. If the flow is below minimum, check for a restriction in the line.
  6.  

The only way to check fuel pump pressure is by connecting an accurate pressure gauge to the fuel line at the carburetor level. Never replace a fuel pump without performing this simple test. If the engine seems to be starving out, check the ignition system first. Also check for a plugged fuel filter or a restricted fuel line before replacing the pump.

 
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