Oh also, check the ignition computer is hooked up correctly (it's over by the windscreen washer tank). If that's unplugged, or the lead going from that to the distributor is compromised, it may also lead to a no spark scenario.
Again thanks, I've had the distributor cap off, twiddled all the leads and basically checked that it is functional in terms of condition but the $64,000 question is that I've replaced three sets of leads with brand new quality remakes from the Netherlands during all this and now I don't have ignition. this is the lead I replaced from dizzy to computer http://www.elbertbos.nl/index.php/en/wire-harnesses/ignition-harnesses/product/76-240-1975-85-distributor-cable
and like most/all of the new wiring the connectors are made in such a way to only install or orientate correctly. I've checked it against the original and it is exactly the same. I provided my VIN to make sure that everything would go painlessly but I'm still a bit paranoid that something is amiss...
Nice cable, I didn't know you could get new ones.

I think the simplest next step is to get another ignition computer and test it. Might also be worth checking the other wires for the ignition computer (I believe there's one going to the alternator?)
Did it go before you played with it?
So you are getting spark from the coil lead but nothing from the plug wires, have a gander up inside the cap and make sure the carbon is still in the center, also that the rotor hasn't sheared the lug that holds the rotor to the dissy shaft.
Will do, these are the other two harnesses:




tbro;99450 wroteDid it go before you played with it?
So you are getting spark from the coil lead but nothing from the plug wires, have a gander up inside the cap and make sure the carbon is still in the center, also that the rotor hasn't sheared the lug that holds the rotor to the dissy shaft.
It did indeed go before I played with it, as far as the rewiring goes I was forced to do something after knocking the connector on the firewall and having the insulation crumble away - it's not a good look! I'm pretty sure a good auto electrician could sort this fairly quickly but being a tightarse I want to give it a go myself, there's also the fact that it's now basically immobile at the top of a winding gravel drive otherwise I could get a tow as I'm an "Ultimate" RACT member but I don't like their chances of getting back down in one piece....

Sorry, just realised I didn't answer your question, apparently there is spark at the coil lead according to the roadside assist guy and certainly nothing from the spark leads. Everything else checks out fine, no damage to the rotor or cap etc. I'm just in the process of comparing the original plug's wiring coding to the replacement to see if there is an issue with transposed/missing wires, the replacement varied in minuscule ways to the original e.g. had an extra green wire for oil gauge and so on...
Both those harnesses are the correct parts as far as I can tell.

Okay so let's continue the troubleshooting. Do you have a multimeter?
Here is the relevant wiring:



Relevant components legend
  • P is coil
  • M is ignition computer
  • N is distributor
Prereqs
  1. Ignition to reds
  2. Confirm 12V between battery positive and negative (give or take a volt)
Confirm coil wired correctly
  1. Verify +12V on coil terminal 15
Verify computer wired correctly
  1. +12V on blue wire
  2. Continuity to coil terminal 1 on white wire
  3. Continuity to battery negative on black wire
If you want to test the signal from the distributor, you might need a logic probe. I've never tested it so not 100% sure. It's worth checking, if you haven't already, that the hall sensor inside the distributor is securely attached to the plug you replaced (the one that comes out the side of the distributor body).
OK, James you've done an amazing job but......here's the breakdown:

I am so grateful I kept the original wiring harness and didn't bin it!! I went back and pulled the boot off the new plug going to the computer and noted down the wire colours.

I then went and did the same to the original one (I didn't have to replace this component in the first place but thought what the hell I'll do all three for piece of mind). The blue and white wires were reversed on the new lead! Substituted the old lead and bloody 'eck the old girl turned over and purred like a dream - from cold!

I'll get back to Elbert who makes the looms and let him know but basically I think I've managed to stumble through this pretty darn well for a rank amateur, many thanks to all who've helped especially James and Tezza who've taught me stuff I would never have known....I'm a happy camper tonight.
Nice! You can probably swap the leads around somewhere in the harness though, so sending it back may not be necessary.
Thanks James, I'm kinda wrapt that I figured out the issue as it's been driving me round the bend! I'll use the old wiring for the time being but I'm guessing it may be possible to pull the terminals out of the new one and swap them over, curious to hear what the manufacturer says but it's probably inevitable that there will be some anomalies from territory to territory (I doubt that it's necessarily an error) but take your point....
4 days later
The car is fully sorted as far as I can tell, I fitted the relay that Tezza sent to me (amazingly generous gesture) and I barely have to form the thought and the car starts! Jumped in and took it for a spin and it's driving better than it has for a long time, the screeching has gone altogether so I must have done something right but I'll never know which component affected the outcome as I swapped out so many....