If You Are Missing Fuel

This procedure applies to a USDM 1992 turbo model. If your vehicle is a different year, or especially if it's naturally aspirated, consult your factory service manual, as the pinouts and presence of certain elements may be different.

At this point, we've determined that you are not getting sufficient fuel at your fuel rail, whether that is none at all, or just a trickle. This could be due to a few faulty items, including:

• Clogged Fuel Filter (Little or No Fuel)

  If you are not getting fuel at the fuel rail, there is a possibility that the fuel pump is working properly, but the flow is being obstructed before the fuel can get to the rail. The most likely place for this to happen is the fuel filter.

  To rule out a clogged fuel filter, all one needs to do is disconnect the inlet of the fuel filter (located on the passenger side of the firewall, in the engine bay), and perform the same test as was done to check for fuel pressence at the fuel rail. If adequate fuel is present before the fuel filter, but is not making it to the fuel rail, the fuel filter is likely obstructed. Try replacing it and perform the fuel rail test again.

  It may also be a good idea to position a helper beside the fuel sending unit (above the fuel tank, behind an access panel in the rear passenger side of the trunk) and listen for the fuel pump activating when jumped, in order to rule out an electrical short if there is no fuel at the fuel filter inlet.

• Initial Fuel Pump Test (Little or No Fuel)

  If your helper did not hear the fuel pump activate, there is an additional step we can take to rule out a short. To rule out a short between the jumper and the fuel pump, try applying 12V directly to the fuel pump. This can be done by unplugging the fuel sending unit and running (+) to the pump's 12V power terminal from a spare battery, and (-) to both of the pump's ground terminals.

  If the pump comes to life and you now get fuel at the rail, you pump is functional and you likely have a short in the 12V power supply to the unit, or the ground connections are both broken.

  If the pump does not come to life, you either have damage to connections in the sender unit, or the pump itself is dead.

• Electrical Short in the Connection (No Fuel)

  Electrical shorts are tedious to test for and discover, and require some basic electrical knowledge. Please read our introduction to vehicle electrical systems before continuing.

  Firstly, before we start testing electrical values, confirm that all of the connectors in the system are snuggly fitted and not damaged. I'll be referencing the electrical diagram for 1992 to determine what connectors are involved. My comments are in blue.

  

  

  

  

  

  

  Looking at this diagram, we can see there are 5 connectors in this wire. They are (in order of occurance starting at the jumper) A-17, C-30, C-34, F14, F-16. For your convenience, I have attached the pin diagrams for each of these connectors above.