1979 Seville EFI system

[Gabeezlebub]

Dear Sirs:
     My father's Caddy is not getting fuel. We would like to check the fuel system fuse and relay before troubleshooting the fuel pump. We can't locate either. Could anyone tell us where these components are located? I have read in some of the literature that some cars do not have a relay switch, and also that some cars have two fuel pumps?! So any info on this would also be helpful. Thanks!!!

[TMoore - NTCLC]

If the car is still running the original EFI system with no modifications, then there is no separate relay for the fuel pumps.

There are two fuel pumps (one pick-up pump located inside the fuel tank, and the external, high-pressure pump mounted on the chassis just above the rear driver's side tire).  When you turn on the key, you should be able to hear these pumps run for approx. two seconds to pressurize the fuel system.

If you do not hear the pumps cycle, check the fuse.  Your ECU is located in the lower middle of the the dash, just above the "hump", and should have a black plastic cover.  If you remove this cover, you will see all of the connections (three plugs - black, blue, and red - several wires each) - in center connector (blue) you will see a brown wire that comes out, and has a glass fuse holder - check this fuse and make sure it is okay - replace if necessary.

One common issue is the that the terminals that connect the ECU to can become loose, and the fuel pump terminal is especially prone to failure.  Check that all of the connectors are securely connected to the ECU, and push slightly on the wires to help assure a good connection.

If after these items are checked, you still do not get the pumps to cycle, you should check the pump - it would be rare for both pumps to fail at the same time.  You can easily check the chassis pump by applying momentary power to see if it runs.

Bruce Roe is our resident expert on these cars, and I am sure that he will chime in shortly with more detailed and helpful info.  He has also documented and recommends installation of an external fuel pump relay.

Good luck - let us know what you find.

[bcroe]

My father's Caddy is not getting fuel. We would like to check the fuel system fuse and relay before troubleshooting the fuel pump. We can't locate either. Could anyone tell us where these components are located? I have read in some of the literature that some cars do not have a relay switch, and also that some cars have two fuel pumps?! So any info on this would also be helpful. Thanks!!! 

The ECU is located on the trans hump, below the dash.  12V Bat and Ign wires come
to it.  There is a fuse in the one to the blue conn pin H.  A relay inside connects pump
power to blue conn pin C.  EXAMINE THIS PIN CAREFULLY FOR DAMAGE, as it is
usually in some stage of burning out from pump current.  It should be powered
for a couple seconds when ign is turned on, or anytime the engine is turning. 
It powers a low pressure pump in the tank, and a high pressure pump in the
frame by the fuel filter.  Pressure should be in the range of 30-39psi, depending
on manifold vacuum. 

There is an external relay fix for the burned pin, I have a kit, also described on the
first album of my PHOTOBUCKET. 

     http://s93.photobucket.com/albums/L71/bcroe/

  click on an Album
  click on a picture to enlarge + description

To work on this cars EFI its best to get manuals; Blue & White 70s book often on
E*ay  253059002414 and I have a few used ones.  good luck, Bruce Roe    CLC # 14630