Wiring Diagrams

Well, I’m sure you have all read the fun we have been having taking the wiring loom apart. We took quite a long time methodically chasing wires, tagging them, understanding them etc. So far this appears to have paid off as we now have a few sections of loom that we are confident about wiring back up. As an example the wipers have their own control unit, which is the only one we will be keeping from the original car. We have the unit off, know what all the cut wires are for, have plugged it back in to the switch on the steering column and Bob would on the face of it be the preverbial.

The one exception to all this is the Heater Blower. Haynes shows a relay, but we have two. The wire colours are close, but only in an annoying way. I have found another wiring diagram which has helped, but I still seem to have a few wires that are the wrong colour, and also ones that are Green on one side of a plug, and Blue on the other. The other small issue is that the new diagram shows the plugs and sockets, which is great. Slight issue is that whilst I am looking at a four pin connector, the diagram shows five, and uses five. Gives me something to do. One issue we may have is that when the gas bottle fell over, one of the things it hit was the heater. The plastic box has taken a fair whack, but also has one or two connectors. We will have to see if these are salvageable.

I have been drawing Pretty pictures of what the loom may look like. Early versions, but I thought I would put them up anyway, at least it proves I have done something. I have seen the wiring on some competition cars, and am not surprised that some of them simply stop working randomly. I was once servicing for someone and the main lead to the starter snapped, vibration I think as it was quite a tight bend in the cable. Anyway, we switched off the isolator, pulled the handle out, went to strip the cable and got an almighty shower of sparks. The main lead clearly did not go through the isolator. This wasn’t an entry level car either.

Now before people start sending mails about fuse sizes being wrong, inconsistencies with wire colour coding (Hopefully only the blower diagram) etc I re-iterate that these are only provisional. There is also the ECU diagram, but the manual for this has a good diagram, so it should only be a matter of adding connectors, wire colours etc.

Update 1

We have been making good progress with the Electrical system now. I sourced some plugs and sockets for getting through the bulkheads. This will allow the whole front loom to be unplugged and removed if required, and also gives a nice place to join wires. We spent some time measuring from both sides before drilling the holes (No Photo yet), only about 2mm out which is good as there are no straight edges to measure from in cars. The fuse box came from Pole Volt (link on Links page). You buy the frame in either 4 or 5 module versions, and then insert the modules you need. The finished thing looks neat and should be more reliable than some of the home made things you see. Given that electrical failure will put you out of an event just as much as a blown engine I never understand the bodge approach generally taken by some people. We will probably retire on the first event with electrical failure now. I will take some more pics of the bits that have arrived. We spent an evening this week working on the loom for the boot. We even had lights working !, although it was off a 12V supply and not the car. We just needed to confirm wire colours. Got some great multi joiners from Vehicle Wiring Products. You know when you need to join three wires and you normally twist two together and then use a butt joiner, but your never sure and there are normally loose strands, just asking to short out, well these devices have spring loaded terminals, and come in various ways upto about 8. You just strip the last few mm, twist the wires and push in. They look very neat and seem to function well.

Update 2

The boot wiring is now complete, and it’s nice to be able to work forward knowing at least one bit is complete. When we stripped the car there was a sensor on the diff, which I had assumed was level or temperature. It turns out to be the speed sensor, and has a proximity sensor and toothed wheel. If the Trip can use this then happy days, so I have installed the wiring just in case.

We were trying to decide where to mount the Battery Isolator. An upright panel in front of the gear stick is traditional, but the panel has to move towards the gear stick a fair way to get enough clearance at the back, and I was worried about hitting it instead of changing gear in the heat of competition. We finally decided on a suitable method by making a wooden mock-up, and then one thing led to another and we thought, make one from carbon. Bit of fun you understand. If it doesn’t work too well then we can go back to making one form steel and covering it. There is more bracing on the back now to help prevent movement, and the overall shape is  coming together. If it goes well you can expect more photos, if it looks like a  dogs dinner then I’m too busy to photograph it.

I was considering how to get suitable cable from the Battery Isolator to the fuse boards, and came across the fuse distribution box you can see in the photos. Looks like a really nice neat solution. You will note that I put the fuses in to prevent them getting lost in the garage, which seems to happen often. Anyway, only 1 of  the 50A fuses is the right way up, which is why it looks like I have installed 05A fuses.

Update 3

Had the regs sent through for an event at Portreath, which is a great venue and one I would love to be at, so put some hours in this week. I know we cannot make it as it’s only six weeks away, but it had the desired effect. The wiring work needs to be done in a good batch so that you can remember all the little details, and why that wire is not connected, and why that one is hanging over the steering column etc. Using the diagrams makes life really easy now, although wire colours constantly change. I simply find the colour I need, find where it goes crimp on the the pin and highlight the diagram to indicate complete. Don’t need to think if it is correct, as that has all been done. Of all the companies I have dealt with only one has ever rung to make sure I knew what I was doing and has ordered the correct part (This was Balance Motorsport for the front Anti Roll bar). So whilst wiring into the relays I realised the contacts for the switched load were much larger, and would need a different contact. So I had to order these, which means a delay and more postage. Given that I had ordered the box, modules, relays, connectors, fuses etc you do think it may have occured to them that I had not got the correct connectors for the relays. Console is looking something like. All the carbon bits arrived yesterday, so looking forward to getting covered in resin. Whilst rubbing down the plug I even flatted some of the paint on the car ready for painting. Just a token effort really.

 Update 4

I navigated for a friend last weekend on the Fat Albert Stages, or as they are often called, Fatal Bert. This renewed vigour and hence updates. Commitment has not wained, and we have worked on the car all year, but it has been the kind of work that is hardly worth mentioning. The wiring is all complete and everything works, even the blower, although I did have to get a replacement connector from the scrapyard. The gauges took ages. There are plenty of electronics on the back  of the dashboard, so we though we would start with a simple warning light, the handbrake. We were not having a warning of this, and it seemed very simple. But we couldn’t get it to work. Checked the bulb, OK. Rechecked that we had enough feeds and returns (4 supplies and 3 returns I think). Lost interest and did something else, came back to it still no luck. Did something else and eventually found the bulb had a bad connection. After this the other warning lights were easy. I also found that the dashboard generates the speed signal that goes to the wipers, radio, computer etc. We wired it up and had the engine turning on the starter in 5th gear (On axle stands), but no speedo. This could be because a/ It is wired incorrectly. b/ The wheels do not turn more than 10mph, which is the minimum speed on the speedo. c/ After turning the engine over there were not enough volts left to make the dash work properly. For the trip you normally count the back of the wheel studs, but there are none sticking through so we used the bolts on the back of the prop. This works OK, although I wonder if the trip can cope with the number of pulses generated. Time will tell.

I have ordered the ECU a DTA S80. This can control the VANOS whereas most cannot. I will have to book a session with Wayne the brain once it is running to get the map sorted. I am hopefull of making noise this year. The list of jobs is now less than 30, but it goes up and down as you cross some off and think of new ones. Some of these are “Engine Oil”, “Diff Oil” etc so not too many big jobs left.

The link below is the dashboard in test mode. Doesn’t really prove anything, just lets you see something working.

Dashboard