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Upgrading wiring to 944 fuel pump

Posted: Mon Apr 22, 2024 5:15 pm
by Tom
This is a re-post from my days on Rennlist, but wanted to capture it here in case helpful to anyone. I did this after mysteriously burning up a couple of 044 pumps. Not at all sure this was the source of that problem, but not a bad idea either way for 044 pump users.

10g pic.webp
10g pic.webp (297.73 KiB) Viewed 959 times
I attached a 10g wire to the positive battery post via a 30 amp inline fuse. I put a tight-fitting piece of curved hose in the grommet, ran the wire(s) through that, and then used heat shrink to seal it all. Had to remove the glove box to get to the other side, and routed the cable down the passenger side of the car...


10g pic2.webp
10g pic2.webp (379.47 KiB) Viewed 959 times
The factory wires to the fuel pump come up through this hole in the hatch floor. I had to remove the grommet that was there, strip away some of the harness sleeve to free the fuel pump harness from the bundle of wires and pull it up into the cabin, so I could use it to trigger the relay...


10g pic3.webp
10g pic3.webp (281.51 KiB) Viewed 959 times
Here's the harness I made. The factory fuel pump harness has a connector under the car. I discovered this is the same connector used on the brake wear sensors, so i found an old brake wear sensor and soldered its connector to the control wires on the relay so that I could connect it all without cutting the factory harness. Sheathing is just what I had handy, with dual wall adhesive-lined heat shrink where needed.


10g pic4.webp
10g pic4.webp (601.21 KiB) Viewed 959 times
Here's the harness in place. I routed the new 10 gauge wires down to the pump using the factory routing/positioning.


10g pic5.webp
10g pic5.webp (362.06 KiB) Viewed 959 times
Rather than try to pull the entire cable, I cut a grommet and worked it into place in lieu of the factory snorkel-style grommet. It's reasonably well sealed as is, but I'll likely cover it all in duck tape or silicon...

Re: Upgrading wiring to 944 fuel pump

Posted: Mon May 06, 2024 12:18 pm
by blade7
Easier on a Euro turbo, with the battery mounted in the rear of the car?

Re: Upgrading wiring to 944 fuel pump

Posted: Wed May 08, 2024 6:45 am
by adonay
blade7 wrote: Mon May 06, 2024 12:18 pm Easier on a Euro turbo, with the battery mounted in the rear of the car?
Only right side driver cars has that that feature

Re: Upgrading wiring to 944 fuel pump

Posted: Wed May 08, 2024 9:11 am
by blade7
Makes more sense to me.