Well its been a really busy few days, lots of bits arriving & due to the cold weather, I have moved from the man cave to the kitchen. I am lucky that my wife is really easy going.
Wiring loom
So to start off I thought that I would put the wiring loom including ecu on the scales, & it came in at 20kgs.
So to start working on the harness I thought that I would simplify things by splitting the loom in to 5 sections. The first section was the main power leads from the battery to the starter etc.
Then the ignition coil & fuel injector loom.
The centre console & handbrake switch
The rear loom, lights & fuel tank etc
Then the main loom.
By splitting the loom into these 5 separate sections, it made things so much easier to sort through. I had the Haynes manual by my side, a mug of coffee, snips & cable ties. I started off stripping all of the insulation tape & flexible conduit off the wiring loom, then put a cable tie loosely around junctions in the wiring so that the loom keeps its shape. this took a few hours to get done properly, due to peoples stupid wiring adaptions that were really dangerous. Basically someone had wrapped bare wires around each other with a bit of insulation tape to secure it, this happened quite a lot throughout the loom. I tried wherever possible to run fresh new cables to eliminate most of the joins, then the ones that had to stay & the factory splices, I soldered the joints up nicely using some flux to get a really nice finish, before sliding heat shrink sleeving over the new repair, to keep the joint secure & water tight.
These are the circuits that I have fully eliminated:
Heater box circuit
Electric windows
Electric mirrors
Interior & console lights
Stereo wiring
Wiper circuits & wiper stalk
Windscreen washers
ABS system
There may be a few others, but I cant remember. The abs wiring was incredibly satisfying to remove ! Pretty much half of the main loom had vanished. I removed the cables from the factory wiring loom connectors aswell, rather than snip the cables & cause a hazard. When I have a bit of time, I am going to work out how small a battery I can use on the car now, as a lot of the main current drawing circuits have been removed. I have kept all of the long runs of cable, as you never know when it may come in handy down the road. Funnily enough, I figured out why the abs light was on, some bright spark cut the cables going to the sensors. If anyone wants a mk1 1.8 abs master cylinder, give me a shout & pay just the postage.
Next up on the electrical side was testing the ignition coils. This is a pretty easy job to do, as long as you have a good multi meter & the specs. First of all, I marked the order that the ht leads go, looking at them from the front of the car. From left to right, it goes cylinder 1 (front plug), cylinder 4 (rear plug), cylinder 3 & finally cylinder 2.
To test the coils, you need to remove them from the engine like so..
Completely remove all wiring & the ht leads from the coils
Sorry about the picture, but basically you have 2 coil types, a primary coil & a secondary coil. Unfortunatley you can only test the primary coil on 1.6 cars pre 1997. So you can only give it a general inspection from cracks & corrosion really, however, you can test the secondary windings on post 97 1.6 engines & all 1.8 engines. If you hold the coil packs in the orientation in the photo below, the primary coil is at the bottom (where the plug leads go for cylinder 1 & 4) & the secondary coil is at the top (where the ht leads go for cylinders 3 & 2).
To test the coils, you must set your multi meter to 20k ohms as in the picture below. (obviously do a continuity test on your test leads to make sure that they are working first).
Then you put the test probes into where the ht leads plug into on the secondary coil (where the ht leads plug into for cylinders 3 & 2). You may find that if your leads are not long enough to touch the bottom of the terminals, you may need to drop a long screw or something like that into the coil terminals, then touch your test leads onto them. It makes no difference which way around the test leads go, you are only measuring resistance.
While doing this, I noticed that one of the coil terminals suffered in the past with a bit of water ingress, so I had to clean it up with a bit of sand paper over a screwdriver, so it could make good contact in future.
As you can see from the picture above, my test result was 9.69k ohms, which was well within spec, meaning its a good coil pack. Double click on the image below to enlarge the picture to see what the specs are. For my mk1 1.8, the minimum resistance was 8.7 k ohm & maximum is 12.9 k ohms.
Now onto the ht leads. I bought a service pack from MX5 heaven which included filters, plugs, leads & spark plugs etc for £53 delivered. But I have made my own leads in the past. If you service your own car & you fancy making your own leads, this is how you do it.
Please excuse me using the old knackered ht terminals & old ht leads, I had no new stuff to hand, but you will get the idea.
So all of the plastic shrouds and rubber boots around the ht leads will just pull off or wriggle loose. Keep them all in order of how they came off.
Then your new ht leads will look something like this. My leads on my MX5 1.8 measured 6mm, so an upgrade was on the cards & I went up to 7mm on the set that I bought.
Then get a very sharp Stanley knife & cut very carefully about 8mm from the end, & cut down to the core, not completely through ! The centre of ht leads very, some have a copper core, some have a carbon type core & others are surpressed, which means that they have a very tightly wound coil around the outside of the ht lead core. Once you cut to the middle of the core, turn the angle of the knife 90 degrees & cut from your first cut to the end of the cable, & peel the insulation off. Do not just pull the waste insulation off ! if the ht lead is surpressed, it will unwind, making a mess & wrecking the lead.
You then fold the core back on itself like so.....
Then place the folded over core face down on your new ht lead terminal.
Use a long nose pliers to wrap the insulation tabs over....
Then use a standard ratchet crimp tool to crimp it up nice & tight.
Then you are done. Obviously you need to feed your insulation and ht lead boots on before you crimp both ends of the cable. HT terminals can be re used if they are in a real nice condition, meaning that all you need to buy is some HT cable. It is really cheap to buy, you will need 2m, you wont use the full 2m, but it only comes in 1m lengths. Below is the kind of HT cable that you need, its a very good sport spec & if your insulation & terminals are good, you can have a brand new set of leads for £5. If your terminals are corroded, or if you fancy using new terminals, car builder solutions sell them in packs of 10 for around £2. There is cheaper HT cable available on ebay etc, this is just the stuff that I like to use.
The ebay uk item number is in the pic above. I have done this loads of times before, but the service kit was so cheap from MX5 heaven, it was not worth me making my own.
I hope this helps, I will put up an injector rebuild guide & a brake master cylinder guide in a bit.
