Help...intermittent spark...sometimes runs, other times not!
 

We've been having trouble getting the car to run, here's a quick rundown of whats were running, nothing special, will only mention what I think could be relevant as fueling side of it is fine. Car is an FC, Ecu is microtech running Bosch HEC coils, microtech igniters, battery relocated to the boot, independent power supply to coils, ecu from battery, magnecor r100 wires.

Something weird going on with this car. It intermittently doesn’t have spark on either Leading 1 or Trailing 1 spark plugs when cranking. Sometimes it has spark on all 4 coils and will fire straight up, you switch the car off, the spark disappears from the front rotor and the car won’t start. Sometimes you crank it over once warmed up and it fires straight away. Sometimes the problem is there cold too.

Doesn’t seem to be temperature dependant, does it when the engine is hot and cold, doesn’t seem voltage dependant, will do it with 13 volts or 10 volts. Mixture and timing adjustments have no effect either. It would appear the coils are being triggered by the ecu and the ignitor, as a test light will “pulse” if you put it across the coil +ve and –ve terminals on all 4 coils and crank the engine over, but there is nothing showing on the timing lights when you put the timing lights onto the plug leads on the front rotor, but there is on the rear rotor.

I have run a new earth wire from the block to the ignitor, thinking that was the problem, fitted additional earth cables from the battery to the chassis, and from the engine to the chassis, thinking poor earths were the problem. I have tried different coils, leads, plugs and ignitors, and CAS, but the problem is still there. I’m at a loss to explain why there is a problem, maybe an ecu fault? It is very random, and I haven’t experienced a problem like this with a Microtech, or any other brand of ecu like this before.

If anyone out has an idea of what it could be, I'd be keen to hear about it...