4 replies to this topic

[croc7]

I'm planning to replace the mechanical fuel pump with an electric one and could use some ideas on the best way to route the wiring through the passenger compartment from the switch panel on the dash to the rear of the car.  My thought was to run the wire over the  heater, down the firewall, then aft through one of the ribs in the floor and under the crossmember but the floor is flush to the beam.  The car is an MKIII and I don't like the idea of removing the headliner to access the wire bundle nor do I like the idea of drilling a couple of holes/grommets in the crossmember. I will if I have to but am looking for a cleaner way.  Any ideas out there?? 

[Icey]

Ours is a Mrk5 shell and I ran all the wiring for the rear under the centre cross-member and through the rear seat. Partially because I just didn't want to route it through the roof but also because I expected to have to make changes...and I did, to add a fuel pump.

We're not running a reverse light so I had a spare wire to the rear of the car, I just re-used it as a trigger for a relay (and fuse) I fitted in the boot.

 

Not a useful solution if you don't have any spare capacity in your existing wiring but I'd suggest if you do run a single wire to the rear of the car that it's properly fused whether it's just a relay trigger or the main pump connection. And if you're not already planning it, I'd also suggest the addition of an inertia switch (I used one from....err....a Volvo I think? Or was it a Maestro? I forget).

 

[coopertaz]

drill a hole at bottom of crosmember lay into ribs and secure with gaffer tape, drill and gromet rear bin out of sight below rear seat then either through into boot that is how it was on girlfriens 92 so copied it when fitting leccy fuel pump to my 82. this was years ago and stilll running fine now. if you do hole low enough on crosmember it will not be any weaker and hidden by carpet

[croc7]

drill a hole at bottom of crosmember lay into ribs and secure with gaffer tape, drill and gromet rear bin out of sight below rear seat then either through into boot that is how it was on girlfriens 92 so copied it when fitting leccy fuel pump to my 82. this was years ago and stilll running fine now. if you do hole low enough on crosmember it will not be any weaker and hidden by carpet

Thanks for the advice, that was my original plan, I’m about 2/3 of the way through the wiring. Just have a couple of holes to drill and grommet. Then confirm continuity. Should be fine.

[croc7]

Ours is a Mrk5 shell and I ran all the wiring for the rear under the centre cross-member and through the rear seat. Partially because I just didn't want to route it through the roof but also because I expected to have to make changes...and I did, to add a fuel pump.

We're not running a reverse light so I had a spare wire to the rear of the car, I just re-used it as a trigger for a relay (and fuse) I fitted in the boot.

Not a useful solution if you don't have any spare capacity in your existing wiring but I'd suggest if you do run a single wire to the rear of the car that it's properly fused whether it's just a relay trigger or the main pump connection. And if you're not already planning it, I'd also suggest the addition of an inertia switch (I used one from....err....a Volvo I think? Or was it a Maestro? I forget).

Yep, ran a single wire from the ignition switch through an on/off switch (theft deterrent) to a 10 amp fuse then to the pump. Velcro’d the fuse housing to the bulkhead underneath the rear seat. Did a continuity check-have battery voltage at the business end-thumbs up.

Edited by croc7, 26 December 2021 - 01:53 AM.