Hi all,

 

Wife's superb failed to start couple of days ago. I had spent some time today digging into it. First scan showed  P00c600 low fuel pressure. I took supply fuel line off before filter and cranked it - no fuel. Dug into tank fuel pump. Could not hear it coming on with ignition, so applied 12v straight to pins 1 and 5 on tank pump- it worked. Then checked voltage on pumps plug- no voltage. Traced positive wire to fuel pump relay (type 646) behind storage box(drivers knee area), wire runs uninterrupted, no shorts. Voltage at relays socket as follows:

pin 1-3v

pin 2- 12v
3- no voltage(not sure where it's running to)
4- not used
5-no voltage(wire running to pumps plug-tank)

 

Any idea what else to check? 

I can remove pumps relay from socket, short pins 2&5 at relays socket, that turns tank pump on for a bit, then relay back in- car starts/runs no probs. Until it's turned off and left for a bit. Then it won't start until I short the tank pump again.

All fuses checked both on side of dash and under bonnet. Swapping relays does not help. Anything else I should be checking ? Cant find electrical diagram anywhere to see where pin 3 wire from relay is running to ? And what else activates tank fuel pump?

Many thanks

Andre  

 

 

Position 3 of the relay socket should have a permanent 12V supply from cabin fuse 27. Check that fuse.

thanks Wino, will look at it again in the morning- weather permitting and will update soonafter 

Solved. Poor contact at fuse f27 hence not supplying 12v to pump relay. Thanks again to Wino.

Nice one.