Longer weekend updates

 This weekend is a bit longer than normal, mainly because it's another change of contract. My last job finished on Thursday, and my new job starts Monday, so a bit longer on the car.

Or more specifically, more time on the wiring. It's like a never ending job. Today I went back over the rear of the car and sorted out all the ground points. This included the fuel tank earth, so for the back of the car it's all set. The only thing I need to do now is to use cable ties to fix it all in place.

Up front I've done one solid ground point near the fuse box, and got several wires terminated and fixed. On the way I picked up a few more wires, specifically the gauge wiring. I've just got the temp sensor now, just one last wire. But I also found a few more wires from the engine side that need wiring.

Now this is where it got complicated again, so I took a break. It was the crank angle sensor this time. The wires are cut short and I wanted to check where they were meant to go.

The CAS has a white red line that doesn't connect to the current white red. I need to use another white red to connect all these;

• CAS
• Main Relay
• Circuit opening relay
• ECU pin 1#B
• Fuel injectors

There's also;

• Black light green which is ground (done).
• White to ECU 2#E
• Yellow Blue to ECU 2#G

The ECU lines are easy enough, then I just need a length of white red to make up the line. 

I also found a few wires going from the ECU to the dash, but it turns out they were related to air conditioning so they came out. I also tidied up the OBD lines, I still don't think I'm keeping the port but at the moment the wires are still there. 

I do need to sort the switches though, I think they're the last three wires remaining from the dash. And the battery is charged and ready to be connected.

(Later that weekend)

Wiring up the white red wasn't too bad in the end, and actually it made the engine wiring look a lot simpler. Now everything is almost in it's correct place I can see a whole load of earths needed. So the plan will be the same as the other side, a nice fat bolt through the bodywork with all the earths hanging off it.

However, I did also find a pretty sorry-looking engine earth strap, so that's going to need replacing. And of course it's a pretty beefy lead so I need to get some decent size terminals to make up a new lead. Fortunately the MX5 battery is in the boot so I have a very long length of thick cable to use as earth and positive leads. Then I need to make up the earth leads for all the sensors, ECU etc. 

Update from the weekend

Not much new going on, but I thought I'd give an update on how things are going with current activities. The bonnet shaping is going well, the corners look a lot better and I've got a couple more sections to add before I can fit the bonnet properly. Then it just needs to be tied down on the ends with the rubber clips I have. I'm not going to fit anything in the holes for now, I don't think that's the way to go and it's clear they're not aligned. More filler I guess.

On the electrics side there's been a decent amount of progress. Today I got all the headlight wiring into the right place, although I've got maybe a handful of terminations to do tomorrow. There was seven pins listed on the diagram, but only six on the actual switch gear. It turns out that I wasn't going nuts, it genuinely was wrong. There was a positive line where there should be ground, and on the other side there was a main beam toggle switch and momentary switch that both do the same thing! I don't know whether part of it is because the light retractor motors have to be powered at the same time. 

Anyway, I've reduced it down to the right level. I have a low power side that energises the headlight relay on position two, and energises the TNS relay on position one and two. There's then a high power side that redirects the headlight relay output either to main or high beam as required. The headlight relay goes off to the headlights (obviously!), then the last lighting stage will be to wire in the TNS relay to the side and rear lights. 

Once the side and rears are lit, I just need to get the last few wires done for the dash lights, then the signal wires for the gauges. They're quite easy though, single wires that are already there and probably just need extending at best. 

Overall it has been a positive weekend. On this journey there's been a fair few setbacks, some have needed very quick solutions and others have been 'I will try this again next week'. The wiring has been the worst, and now I know why. It wasn't just me not getting it, it was genuinely wrong. There really isn't much more now, as soon as it's running and the last bits are bolted/screwed/rivetted in place it can go for IVA. I still need to make the decision on whether to make it perfect for IVA (paint, decoration etc), or get it IVA ready then continue the work after. Having it road legal would not be the end either way, that's simply not how kit cars work! 

(Update...) And of course just typing that I've remembered something. For IVA the edge of the bonnet needs the clip on trim, but the bonnet bumpers for positioning don't currently permit the edge trim. So if I go with what I have, each of the bumpers needs reprinting with a notch missing. Fortunately I've got to reprint four anyway so I'll get the notch in those straight off. 

Bonnet reshaping

 After I'd cut the rear wheel studs and got everything sat straight, I decided to have a go at the bonnet. It still doesn't line up properly. Well, it doesn't line up properly for me! The trailing edge sits half an inch or so lower than the body. I had thought it just needed some padding, which is why I bought the extra foam strip. Turns out it needs a bit more than that.

What I've done is drill holes on the corners, one about three inches in from the top and one about three inches down, both sides. Then using a nut and bolt I was able to dial in good positioning for the corners. I could do with a bit more working space but actually it worked quite well. 

The bonnet sides now need to be curved to match the body sides. The middle part needs to come out, and the bottom needs to be pulled in. That will work well with the bonnet catches I have, I just need to make sure there are suitable fixing points all the way round. I'm not convinced foam is the best way to go, although it will stop the squeaking that currently happens when I roll it in and out of the garage! I think I'm back to 3D printed brackets, not as big and bulky as the ones I did before but probably more curved to allow the bonnet to drop into place. And they will reuse the holes I've made doing the bolt adjusters, so they should be very secure. 

What to do when you lose some wires...

 This weekend hasn't got off to a good start. I had hoped that with the sunny weather I'd get the wiring done, then potentially get the car running. Of course, something had to go wrong. 

That something turned out to be an absence of relays. As anyone who does car wiring knows, there are various circuits that are a little too high powered to run through the switch, and therefore need a relay in attendance to keep things from melting. Just going through the component locator on the wiring diagram, there is;

• A/C relay (not needed)
• Blower motor relay (not needed)
• Circuit opening relay (needed, page 2 C4)
• Cooling fan relay (needed, page 3 E10)
• Headlight relay (needed, page 4 D14)
• Horn relay (needed, page 5 C17)
• Main relay (needed, page 2 E4)
• Retractor relay (not needed)
• TNS relay (needed, page 4 E14)

So that's nine relays, of which I need six. 

• The circuit opening relay is not a standard one. It's got VIO and BLK for energising the relay, blu-red to the fuel tank unit, wht-red which is similar to the main relay, and lt grn which goes to the air flow meter for some reason? This sits on it's own and is already wired up, I remember doing this one yesterday for the fuel pump;

• The cooling fan relay is a regular 4 pin, with blk-wht and blk-grn to energise the relay, blk-red from the cooling fan fuse and yel off to the cooling fan motor. This is inside the fuse box, you can just see the yellow wire exiting stage left;

• The headlight relay is a regular 4 pin, red-blu and blu-yel to energise the relay, red-blu to the headlight switch and wht-blk also to the headlight switch. This is gone, I can't see any sign of it.
• The horn relay is a regular 4 pin, grn-org and wht-grn to energise the relay, wht-grn to the stop fuse and grn-red to the horn. For some reason I still have this one, it was on it's own and I think it must have been kept as part of the horn circuit;

• The main relay is a regular 4 pin, blk-wht and blak to energise the relay, wht-red off to various points on the engine and wht-grn to the injector fuse. I say this is a 'regular' relay, it's a bit beefy compared to the ones above. This also lives in the fuse box and is the largest box in there;

• The TNS relay is a regular 4 pin, lt-grn and wht-red to energise the relay, wht-red from the btn fuse and wht-blu to the tail fuse. And this is gone, it'll be with the headlight relay no doubt but no idea where either of them are.

So this leaves me with a decision to make. Overall I'm going to go visit AliExpress and buy a small relay board for the missing relays. But that's now a third box on my ever decreasing electrical platform;

Even this screenshot is missing the circuit opening relay and indicator flasher, so there is precious little space left. However, the box on the bottom is just a fuse box, it does nothing clever. I am wondering whether I should buy a combined relay/fuse box, and do away with the unit at the bottom. It shouldn't be too bad to rewire, the unit I'm considering from AliExpress comes prewired so I just need to buzz them out and make sure I still have wires going where I need them. 

That fuse box is made up of 17 holes, of which 7 are already empty. From the remainder I need;

• 15A engine
• 10A tail
• 10A meter
• 10A stop
• 10A Hazard

There's also a 15A Fog fuse that I'd like to move out of the larger unit. I can't take anything else out of there because they're all the larger fuses (30A to 80A) and I'm not trusting an AliExpress special to carry that sort of current! 

So that's six fuses needed, I might add a couple spares just in case. For the above relays I have Cooling, Headlight, Horn and TNS to add/replace, all 4 pin. Again I might add one or two spare slots. 

(Five minutes later). So it looks like the prewired ones are no good, they went cheap and put common rails on the fuses and relays. So for the various combinations needed for the car, a common rail is not an option. Shame really, the one I found has six relays and 10 fuses which would have been perfect. I do have one that will work well though, 4 relay and six fuses. It'll be compact, and no spare slots, but that's probably a good thing. Once it arrives I'll get it in place for the fuses, then carry on with the relays. Then hopefully that's the electrics finally done.

In other news, I trimmed the studs on the passenger side rear hub yesterday, so now that wheel sits flush on the spacer. I need to do drivers side shortly, then that's another job ticked off. I could try fitting the rear calipers and the handbrake cables, that may be an easy-ish job to do.