I've had the car a few months and don't have much history on it. It's meant to be a cheap runabout for me to hone my light maintainence skills and learn a bit more from unfortunately...

I now seem stuck with an electrical problem that seems almost overwhelming.

The car has on occasion started to misfire - bounced around like I was a learner driver - accross the rev range.

This may be unrelated, but I'm sure it was damp whenever this has happened.

Then on Thursday night - she shuddered, died - and wouldn't even turn over.

Cause, fuse 13 (20A) is blown - the fuse box shows an engine diagram.

By replacing this fuse, I got the car to start again, but the misfiring persists.

Digging into my Haines manual - I see that this fuse is for the "cold start valve, engine management system and fuel shut off"

Assuming fuel shut off and inertia switch are the same thing. I thought I'd test this system - I reset it. The problem persists. So disconnected it - at which point it might have been stupid to try and crank the engine to make sure starter works. The starter did turn... once and the fuse went again. I removed and short circuited the inertia switch - and blew another fuse. My conclusion - the inertia switch is fine (and I shouldn't waste fuses being a dumbass).

In any event now the car will not start - I've decided stop popping fuses like <insert inappropriate idiom>.

From digging into the wiring diagram (or newly aquired Haines manual) I have the follow conclusions.

- I have a post-95 fuse box and PTE engine system, but an old wiring look - fuses (and I think relays) match, but wiring colours do not. This should make thing interesting from here on.

- car wiring diagram terms don't correlate to normal language terms - e.g. wiring diagram refers to "power hold relay" a.k.a. R2 / Fuel Injection, ECU relay. e.g. Electronic DIS module a.k.a. Ingnition module.

- Fuse 13 supplies 12V (pullup power) to ECU, ingnition module, "injector resistor", "Canister purge solanoid", Fuel injectror and speed sensor. This is done through the output of R2 (the dubiously named 'power hold relay')

- The output of R2 is also used to pull up the fuel pump relay (R3). This would seem to explain my fuel starvation symptoms . While fault/short has been developing it's been pulling current and away from R3 and de-activating the fuel pump.

- I currently have a short either in cables or systems mentioned above down circuit of F13. Unless, someone can explain how current could flow the other way into a shorted relay - I'd be keen to hear. I need to isolate the offending part to conclude my diagnosis - and that is going to be a pig of a problem. I have the following problems:

= wiring loom isn't as to manual - so I need to figure this out from first principles (and hope it's consistant)

= no pin outs for the various modules/components - so how do I if they are shorted out - is there a convention for numbering?

= I'm not sure where/what some of these things are - ECU and ignition module are easy the others?

= I suspect this is a wiring problem - the fact that it was eratic before, moving the car helped when it cut out, etc.
Is second hand loom the best option here (as apposed to trying to find (isolate the offending bits) and rewire?

Needless to say, any additional tips/tricks/help or info that could assist at this stage would be greatly appreciated.