Engine & Battery Loom

 I decided that I was going to run an Emerald K6+ ECU and throttle bodies, so it made sense (at least for ease) to use the GBS wiring loom. I was hoping the £600+ price tag meant it would be super easy..... To be fair it does make it much easier, but there is still a fair bit to do.

I received the loom and battery lead kit from KitSpares. The loom is well marked and looks good quality. The battery lead kit came missing the terminal covers, and as soon as I picked up one of the cables the crimp came off one end. Quick call to GBS and it was sorted very quickly indeed.

First job was battery lead from battery to starter. I decided to run this low past the RHS engine mount in some split conduit p clipped and cable tie mounted at IVA compliant intervals. I would use that same conduit to run the cable to the crankshaft sensor on the bottom front left of the engine. Since GBS provide a plug to take both the cam and crank sensor wiring, I had to make up this bit of the loom. I sourced some wire from my existing Mazda loom, bought a new camshaft plug & pins (BOFI racing) and also managed to source the crankshaft loom side connector from eBay albeit from China. Some crimping and swearing later, I had a mini loom! My wire colours have changed from standard, so here is a record of them....... 

Cam & Crank Sensor

Sensor    GBS Pin    GBS Wire Colour    Mazda Wire Colour    Rob's Wire Colour

Crank 12v      1           Black                  White / Red            Orange

Crank Sig       2           White                 Purple                   Purple / Red Stripe

Crank Grd      3            Blue                  Black / Blue           Yellow / Green Stripe

Cam 12v        1            Black                White / Red            Yellow / Red Stripe

Cam Sig         4           White                 Grey / Blue            Purple / Blue Stripe

Cam Grd        5            Blue                   Black / Blue           Yellow / Black Stripe

The battery cable and crankshaft loom run in the split conduit past the engine mount

The battery lead p clips to the battery earth point. Battery earth cable is attached ready for the battery

Crank shaft sensor wiring comes out of the split conduit. Needs securing with some cable ties.

Should not forget the engine earth on the exhaust side of the engine

Engine Earth

Next was the VVT sensor. Loom tail far to short so I bought a new connector and made up a new loom myself.

Next the the coil pack loom needed to be sorted.

Function    GBS Wire Colour    Mazda Wire Colour

Cyl 1&4     White                    Brown / White

Cyl 2&3     Yellow                   Black / Yellow

Ground      Brown                   Black

12v            Black                    Black / White

Coil Pack Loom

Now for the main loom, the first job was to position the ECU as a monument for the loom. I copied an idea from a well known blog and use a piece of aluminium to extend the fuse box mounting plate to place the ECU beside it. The loom from the ECU plug was then routed to the left into the tunnel.

Emerald ECU attached to aluminium plate

Loom routed to the left of the ECU to leave access to the brake pipe union. The tied to the brake pipe before entering the tunnel

By my reckoning, the loom had too much of a tail on it and so would need to be routed to effectively shorten it. Therefore, I took the loom cable to the left of the fusebox and into the area above the gearbox to give myself room to lose some length. I then figured the best place for all the engine loom connectors was on the RHS (intake) side of the engine and try to hide them underneath throttle bodies. 

I also ran the fuse box to starter motor battery cable into the tunnel at the same location.

Engine loom and battery link into tunnel to the left

Losing some length in the space above the gear box. Whilst it's not that pretty, it is very secure and out of sight. To relieve congestion, I ran the battery cable out of the tunnel on the LHS and take it across the engine bay slightly ahead of the chassis cross member.

Losing length on the engine loom

Using a piece of aluminium L section attached to the two circular chassis members through P-Clips I run the battery cable across the engine bay and will also run the cable for the lambda sensor to be secure and out of sight.

Aluminium L Section To hide some more cables

The engine loom exits the tunnel on the rear RHS of the engine. Because of the loom design all the connectors are close together, but I didn't wanted something a bit neater than just tieing them to the tubular chassis member. So I made an aluminium bracket to secure a bridge across the chassis for all the engine connectors bar the lambda connector. I rivetted some Deutsch connector clips to the bracket so they are securely held and can't drop onto the steering column whilst also not able to chafe with fuel pipes or other bits. They can also be released quite quickly in case removal is needed. The cables are mostly hidden underneath the air filter so whilst not invisible are not unsightly. May tidy a bit more in future.

Engine Connector bracket