1985 jag no fuel

MATT5566

MEMBER
1985 JAGUAR XJ6

I have a 1985 Jag XJ6 with 85000 miles and I can't seem to get power to the fuel pump. I have checked the fuse and the fuel relay, and replaced them, along with the fuel pump. The grounding is good. Is there any where I missed to solve this problem. Could it be in some sort of fuel control system, I.E. Throtle body, ECU. Any help would much appriciated thanks

1 Reply

JAMES W.

MECHANIC
2,395 POSTS

Question, do you have spark? If YES, The fuel pump relay is feed from the main relay, check this. Main relay sends + voltage to the FP relay coil which is grounded by the ECM to close the relay and start the F pump.
Relay terminals. (Bottom of relay).
#30 power in to fuel pump
#87 power out to fuel pump.
#85 power to coil. (From main relay)
#86 ground to coil. (From ECM)
If you have no power to #30, it should be a fuse.
If no power to #85 (key on) check the main relay.
If you DO have power to #85, probe term #86 with an "incandesant test light". This should ground and close the relay starting the F pump. If so, you have no output from the ECM. I use a spare relay with the plastic cap removed for tests. With this inserted you can physically see if the relay is closing and you can manuall close the to act as a jumper. You can also use this for the ign on and main relays. Hope this helps. If you also have no spark, check your ign on relay.