GM Caprice 1990-1993 Repair Guide

Fuel Filter

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There are three different types of fuel filters that may be used on the Caprice: internal filter, in-line filter and an in-tank filter.

The internal filter is used on all carburetors and is located in the inlet fitting. A spring is installed behind the filter to hold the filter outward, sealing it against the inlet fitting. A check valve is also built into the fuel filter element to prevent fuel from draining back out of the carburetor when the engine is not running.

The in-line fuel filter is just that, installed in the fuel tank-to-engine fuel line, usually mounted near the rear crossmember of the Caprice. The lines are made of nylon and care must be taken not to kink the lines.

The in-tank fuel filter is located on the lower end of the fuel pick-up tube in the fuel tank. The filter is made of woven plastic and prevents dirt from entering the fuel line and also stops water unless the filter becomes completely submerged in water. This filter is self-cleaning and normally requires no maintenance.

REMOVAL & INSTALLATION




CAUTION
Never smoke when working around gasoline! Avoid all sources of sparks or ignition. Gasoline vapors are EXTREMELY volatile!

Carbureted Engine

See Figure 1



Click image to see an enlarged view

Fig. Fig. 1: Replacing carburetor fuel filter- 5.0L (VIN Y) engine

To avoid twisting or kinking a brake, oil or fuel line, always use a backup wrench when loosening and/or tightening the line.

  1. Disconnect the negative battery cable.
  2.  
  3. Remove the air cleaner assembly. Disconnect the fuel line connection at the fuel inlet filter nut using 2 wrenches.
  4.  
  5. Remove the fuel inlet nut from the carburetor.
  6.  
  7. Remove the fuel filter and spring.
  8.  
  9. To install, replace the fuel filter.
  10.  

The fuel filter has a built in check valve and must be installed with the check valve to meet with safety standards. Ensure the check valve is not sticking closed by lightly pushing the valve open.

  1. Install the filter spring, filter and check valve assembly in carburetor. The check valve end of filter should face toward the fuel line. The ribs on the closed end of the filter element will prevent the filter from being installed incorrectly unless it is forced.
  2.  
  3. Install the nut in the carburetor and tighten nut to 46 ft. lbs. (62 Nm).
  4.  
  5. Install the fuel line and tighten connection. Reconnect the negative battery cable.
  6.  
  7. Start the engine and check for leaks. Install the air cleaner.
  8.  

In-Line Filter

See Figures 2 and 3



Click image to see an enlarged view

Fig. Fig. 2: In-line fuel filter replacement- fuel injected engines



Click image to see an enlarged view

Fig. Fig. 3: Fuel filter location, right side forward of rear axle- fuel injected engines


CAUTION
Before removing any component of the fuel system, make sure the fuel system pressure is properly relieved as described in this section.

  1. Disconnect the negative battery cable. Disconnect the nylon fuel line fittings by squeezing the plastic tabs of the male connector together, twisting the lines a 1 / 4 turn and pulling the connection apart. Repeat the procedure for the remaining line.
  2.  
  3. Remove the fuel filter from the retainer or mounting bolt.
  4.  
  5. To install, reverse the removal procedures. Start the engine and check for leaks.
  6.  


NOTE
The filter has an arrow (fuel flow direction) on the side of the case, be sure to install it correctly in the system, with the arrow facing in the direction of flow toward the front of the vehicle.

In-Tank Filter

To service the in-tank fuel filter, refer to the Electric Fuel Pump Removal and Installation procedure in Fuel System .

FUEL PRESSURE RELEASE



Carbureted Engine

To release the fuel pressure on the carbureted system, remove and replace the fuel tank cap.

Fuel Injected Engine

The TBI unit used on the fuel injected engines contains a constant bleed feature in the pressure regulator that relieves pressure any time the engine is turned off. Therefore, no special relief procedure is required, however, a small amount of fuel may be released when the fuel line is disconnected.


CAUTION
To reduce the chance of personal injury, cover the fuel line with cloth to collect the fuel and then place the cloth in an approved container.

 
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