1985 jag no fuel

1985 JAGUAR XJ6

MATT5566

MEMBER
1 POST

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

Aug 10, 2007 at 2:27 PM

JAMES W.

✓Experienced Mechanic
2,394 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.

Oct 5, 2008 at 11:15 AM

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