Speeduino – Rover SD1, A New Loom Begins

I havent been updating this much, but progress has been steady. Over the past few days I have been working on making the new loom, wire  by wire.

Every day it’s been a case of coming home, having dinner and then spending the rest of the evening out in the garage working on the Rover. It is finally coming together though.

I started work on the new loom on Monday. The basis for the loom is a Megasquirt wiring bundle from DIYAutoTune (although if I were to do it again I would use the MS3X loom as its labelling is more relevant), two 7M rolls of 3mm yellow wire, and a roll each of 10M 4mm red and black wire. I used the yellow wire as my power feed from the resistor to the injectors, as it’s not overly important which injector it goes to, and its also a heavier gauge wire than the DIYAT wire.

The first wires I laid down were the ground triggers for the two banks of injectors. On the standard Lucas system the injectors are banked left and right (odd and even), but these days it’s better practice to group them based on the firing order. In my case I grouped 1467 together, and 2358 together. This is apparently the same as some Chevy engines.

This made actually running the wires a little more complex, but it’s not hard when you get your head around where it’s all going.

In hindsight I should have left it on the engine and built the rest of the loom around it, but hey, live and learn. I have also decided that zip ties are only good for guiding the cables into bundles (guiding the wires where you want them), but not actually for bundling the wires together, good quality insulation tape is better for that (although use it sparingly and temporarily).

This is the basic plan I was working to

Next up was the power wires for the injectors, from the resistor pack on the LH inner guard.

From there I just kept adding more and more wires to the loom. TPS, Coil triggers, power feeds, grounds, etc etc. This was also the point where I was sick of looking at the ugly old ignition leads, so off they came.

Coil wiring. Power feed, ground and trigger wires.

Crank position sensor shielded wire and bracket (which still needs some tweaking so it won’t eat the insulation)

I had a rest yesterday as I was waiting on an order of some more yellow wire, and instead fixed the fuel leak on Project Mustang, and mowed the lawn. Started first pull when cold, which is amazing for an early 70s mower I picked up from the junkyard.

Today I had my wire arrive so I got stuck in and ran the rest of the wires for the loom. I haven’t put them through into the car or trimmed them to length yet, so it’s huge.

With all the wires going where I needed them, I did some temporary taping to hold the wires together, and then removed it from the car ready for final tweaking and then having the loom tape and braided sleeve fitted.

I did some basic future proofing too, but running a third wire to the Extra Air Valve, so if  i choose to change to a proper Idle Air Valve to control idle, the wire will already be in the loom. Same with me running a trigger wire for an electric radiator fan. Although I’m not running one now, I may in the future and it saves me running the wire from the ECU later.

Once its all looking nice the loom will go back on the engine, the wires cut to length and then plugs added. I still need to do the end of the loom that goes in the car, and the relays, but I’ll get there soon. Some brave pills will be needed to cut the loom in half so I can install the connectors that make the loom two sections.