Category Archives: wiring

Wiring, wiring, wiring

35+400  =  435

Well, what have I been doing on the car of recent? Wiring, and a lot of it. It’s gone from completely insurmountable to feeling like I’m breaking the back of it and 90% there – however, it’s felt like it’s been 90% for some time now, feel like I actually could be…

Bits of note? Removing wire, lots of it, tracing back and tracking, relying on the wiring diagrams (which have been pretty damn accurate).

A few fun bits, getting the headlights working – a specific cause of pain was the main beam indicator light – the reason for the pain was the Venom headlights, and their solenoid that actuates the dipped/main beam – what it turns out is that switching a solenoid on and off causes a spike back of voltage – how do I know this? because it caused me to blow £10 worth of main beam LED indicator light – argh. With a lot of help from my pals Rob and Amit they pointed me to a “flyback” diode – quite a common solution apparently, and it’s done the job brilliantly.

Other fun? an ECU light, it turns out all UK cars didn’t have an ECU light on the dash – but I quite fancied one, however after a lot of research, it looks like I can take a feed from the diagnostic port on the car (not OBD II). Downside is that I have an ECU light that is permanently on unless I join some jumpers in the diag port – upside is I can disconnect it for most things, and run it depending on how I feel, not sure on it yet.

Final bit of oddity is the battery charge light – this would be really easy if I were using bulbs, bulbs you see accept current in either direction – I’m using an LED for my dash lights – they accept current in only one direction. I toyed with the idea of using a bridge rectifier to allow the battery dead, alternator ok OR battery ok, alternator dead to trigger the light, but after much fiddling and testing I’ve decided to just emulate the MX5 usage, just feeds off the alternator. Another thing I learnt is about exciting current of alternators – as I remove the bulb (and resistor) from the mx5 cluster there is no device to draw some current while the alternator starts doing its thing. So I’ve got the LED, but also a resistor in there to for some current to kick the alternator off. I have to thank WSCC and Mark Wendon again for some thinking and nudging along the plan!

Another nice Segway was the flasher unit indicator mod, well documented out there (did I even mention it already!?) needed to up the resistor to ensure the system can use LED indicators.

Right now…

I’ve the speedo to fit – thinking is to attach the hall effect sensor to the diff arm and read off magnets I’ll stick to a driveshaft. So need to fit this (bracket is done already), line up the wiring.

Then need to route the wiring for the heated screen – when this is done I should be about done with adding and fiddling with wiring.

Dare I say pretty much everything else seems to work, gauges, lights, switches, warning lights and so on.

then need to bundle up the wires up, locate all the oddies like fuseboxes and indicator switchboxes etc. Then tidy the wiring up under the bonnet.

Getting there – must say I’ll be pleased to see the back of the wiring – especially as I’ve a rollbar sat in the spareroom I’d love to fit!

Laura helped lots by the way… she likes a call out…WP_20150915_19_45_01_Pro WP_20150920_20_26_56_Pro WP_20151001_19_23_05_Pro WP_20151014_19_23_55_Pro WP_20151014_19_24_32_Pro WP_20151019_20_42_28_Pro WP_20151019_20_42_37_Pro WP_20151022_19_46_17_Pro WP_20151022_19_49_47_Pro WP_20151022_20_31_28_Pro WP_20151027_20_03_18_Pro WP_20151027_21_25_07_Pro WP_20151113_14_50_51_Pro WP_20151113_15_43_08_Pro WP_20151208_17_52_25_Pro WP_20151210_17_47_07_Pro WP_20151213_20_14_05_Pro 1

some piccies…

Everything from May 2015 to Oct 2015!

43+357 = 400!

Yes, both hit my 400th hour (an accurate approximation) and here goes an update covering many  months of build…

I will let the pictures speak all 26 of them, but a few areas of note:

Since I’ve had fluid in the rad I’ve had little puddles of water and drips on the rad fins – odd given it’s a car that’s done zero miles. After more drying, testing etc I bit the bullet that it was leaking on one of the cores – a call to WF to learn it was an out of warranty part (a reflection on build time I guess!?) – so a new rad 😦 refitted and lo and behold there are no more leaks – I can only imagine one time it had not enough antifreeze and expanded over a winter – hard to guess -either way, dry garage.

The rear end – built up over time, rear clusters first – as you can see I’ve chosen the traditional “trailer lights”. Appreciate they are a bit of a personal choice – but I  quite like them. They’re up and running. The only error here was wiring the Side and Brake light the wrong way around – it transpires brake should be brighter than Stop – makes sense, but still managed to get the wrong way, a quick fix -thanks WSCC!

Fog and Reverse light are courtesy of playschool and some black moulded plastic housing – they are probably  bigger than I thought but I quite like the look.

For what it’s worth the number plate light is a beast – a black sprayed aluminium LED unit. It was £26 when alternatives were far less, but it really caught my eye – don’t tell laura…

And the number plate – P138 LOA, that’s the donor car – for illustrative purposes only… after a few thoughts from WSCC I won’t give the plate a bracket etc – mount direct to tub.

Since I’ve trial fitted the bodywork I;ve done a bit of reading on fitting the nose cone, the default is bolts into the rivnuts in chassis – it was just a bit cumbersome IMO. I’ve since added Dzus slide latches to the two top nose cone mounts – another idea I’d steal from the forum!

Another little change is a bracket to allow the steering column around a bit – this should allow access to the ignition from just under the padded dash. Little mod, and easy when the drill penetrated the bracket I’ve used – hopefully will do the job.

Also an extra hole in the bodywork – a bit one for the exhaust manifold – there is no easy way (I’ve found) for getting this in the right place as you’re essentially measuring in 3 dimensions – ended up with a little cardboard template and a deep breathe. Optomistically I measured the square made by the 4 exhaust manifold branches(?) this was around 100mm x 100mm – so that’s the hole I drilled and opened. Then trying to manipulate the manifold into this it was clear that was never going to work – not with the engine in and the bodywork fixed(oh yes, I fixed the bodywork). Essentially I opened up the manifold up – mainly in the horizontal plane. The result is that it goes in and out, just. The result is also that when the manifold is in there is a little space either side, this just seems to be the way (unless you take the engine out, don’t fix the bodywork, or fit a surround).

What you may recognise in some of the pics is a padded dash. This may look familiar to those that follow other blogs, it’s KugaWesties previous padded dash. The plan is to switch to a flatter carbon dash post IVA, but with my option of VDO gauges they need recessing to meet radiusing.

Final work in the recent months is wiring. What can I say, it takes an age. A piece of the build I was really fearing but tobe honest I’ve rather enjoyed it- it’s made electronics knowledge from design tech A level worth it. So far I have removed 95% of the wires leaving the car. A few elusive ones, I’ve included a pic of the air conditioning connector, that was a mystery for a while (thanks WSCC – kugawestie again!). The dials are now on order and I guess the fun will begin adding headlights (going for all in ones(Venoms)) and wiring the dash.

That’s all for now!

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Tunnel top panels and starting main loom

25hrs + 302hrs = 327 hours

The easy and quite satisfying part here was the aluminium transmission tunnel panels, they needed a little fettling – but nothing much, and with rivnuts inserted some nice flush hex heads hold down the panels – some foam to stop any rattling, and the grommets in the big holes to neaten things up a bit and stop any chaffing :S

The beastly bit in the last couple of months has been starting with the main loom, hard to really be able to say much of value here. It’s taken an age, I’ve not a lot to show for it, and I’ve a long way to go with the wiring!

It’s gone from a box (or two) and is now somewhere laid out in the chassis. I have at least fitted the ECU, it’s plate etc, another nice rewarding little job.

Oh and made a blanking plate for the EGR system on the inlet manifold.

I’m now at the stage where I think everything that needs to be plugged in is. A few queries, answered in other posts and I don’t doubt there will be a load more head scratching.

Not long and fuel, water and electric can be added and it can be turned over 🙂 Need a garage door fitting first (on order)! and have the bodywork for collection early Jan.

While I can’t fire it up, nor fit any bodywork I will be doing the bits of main loom I’m confident with and I won’t live to regret when/if the thing doesn’t start!

More to follow… and happy Christmas all – especially those on WSCC who just keep helping


blanking plate car front on car top down loom in a box loom laid main loom tunnel top panels tunnel top panels2

Mystery wires solved

With thanks to the folks at WSCC (see post  )

So it turns out the female terminal near the coil pack is for the water temperature gauge (as opposed to the ECU feed now at the front of the engine).

And the male terminal sits just to the LH side of the coil pack cunningly hidden. A bit of multimeter action proved that this with continuity between the female and a terminal on the instrument cluster (I don’t recall which, 2J or 2L maybe!?)


The other wire… That comes from the gearbox electrics, so either a neutral or reverse switch. In this instance its a neutral switch.

Again multimeter and  continuity proved this. What has transpired is that it’s not required, it seems to earth in the gearbox – also the feed from the neutral switch gets OR’d with a feed from the clutch switch – so either youre in neutral OR the clutch is depressed to send this signal to the ECU, and the clutch switch is already earthed. Either way some testing with the multimeter shows I don’t seem to need the earth wire – nor did the mx5 I suspect.

A proper post to follow…!

Mystery wires…

Not really a post this one, but a placeholder for the immense knowledge of WSCC!

If anyone can advise on what these wires are…

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Rear wiring loom, moving house and turning the car sideways

30+272 = 302hours (blimey, over 300 hours now…)

Yes, I know, it’s been a LONG time since the last post, 5 months! Quite a hectic set of months though with some holiday, a house move, little ones first birthday to mention a few things. However a nudge from the forums has reminded me I have a blog to update too – you know who you are 🙂

Also a bit of another landmark of being over 300 hours – now well over double the time WF quote, maybe I read that in the, er, manual…

Main progress since the last update has been in wiring, in my case the rear loom, servicing the rear light clusters, fuel pump, sender, handbrake switch etc etc

I don’t profess to me much of an electrician but from A level electronics I have some idea – but it’s just shown me how rusty I am! Its also taken me a while to get my hear around a few principals that are isolated to auto electrics – like the car is a big negative earth terminal, no one ever spells that out.

And sill things like how do you choose the right wire size to add? As ever guidance on WSCC forum answered this, and it’s obvious, but a size bigger than the fuse in that circuit, again, makes sense, but not something ive ever seen spelt out – I guess clever people would rate the load on the circuit!

ps. learning ohms law was good all those years ago, turns out it applies here.

before I get onto the rear loom…

also moved house in this time frame – this is only of note because… old house had a standard size single garage. new house has a double length single width garage – great!


there is no garage door… the kind previous owners swapped this out for a 3ft wide pvc door 🙂

thanks to an excellent removal company, several burly men, my sister, piano moving wheels, ratchet straps etc the car was turned on it’s side, rested on it’s wheels and manhandled/wheeled through the narrow doors! when it’s road worthy I will have a nice garage door fitted – insert quip on when this may be.

rear loom… the manual is pretty good here, the first job is stripping off all the miles of insulation tape, excess crap etc. Unplugging from the main loom at the two connectors.

I then went on to label everything, which has since proven sensible.

add a handbrake switch cable, then work on the rear lights, starting to cut and route the cables.

lots of jiggery later and all the old, unnecessary cables removed. a couple of pics of the loom new and old wires – already quite a lot to go…

rear loom then trial fitted into place several times, with tape and convoluted piping in place

for the light clusters I’ve used some econoseal connectors, these seem pretty good – the ratchet crimper for these seems a must to get a decent connection.

for other crimping I’ve invested in a draper expert crimping tool and a lot of their connectors of various sorts – hopefully this should to 9/10 of what I  need.

I think that’s if, just need to get my earths fitted into the rear diff gusset (looking to use Grahams technique of getting a decent earth (rivet, wet and dry, washer, rubber etc))

fit the loom with some cable tie connectors


pics below…


oh, and forgot… added the fuel tank earth and vent pipe

car on trailer car outside car under wraps connectors between front and back loom econoseal connectors excess wire from rear loom fuel tank earth fuel vent pipe loom power loom rear loom finished rear wiring loom