OK, that does tend to imply that the ECU is sending a signal to the low voltage side of the coil(s). Does it seem to be roughly in time with the rate the engine is cranking?

I assume that the fuel pump is turning: can you hear it while you are cranking (not just while the ignition is on)?

Can you smell petrol while cranking? Sniff the exhaust when you stop cranking for a few seconds.

The supressor cap (depending on manufacture) could be either a shiny cylinder an inch long with a wire coming out, with the case screwed to the chassis and the wire connecting to the coil (I am still not sure if you are can or transformer type). Alternatively, it might be a black plastic oblong about the size of a small box of matches, again bolted to chassis and the lead going to either the frame or the low tension side of the coil. I would guess since you are ECU with injection and no points (I assume???) that you will not have a points supressor (shiney can either in the distributor or outside on the LT wire) but will have an interference supressor (black plastic block).

If the supressor cap goes short, then the signal from the ECU will simply run to earth and not reach the LT side of the coil. Hence, examine the coil, and find the power lead (if it's can) or the ECU input line (transformer) and make sure that only these leads are connected. You will probably need to check the ignition circuit cct diagram in the manual (hope you have one) as I can only generalise here. If you are sure that only the input lead to the coil is connected, and the frame is earthed, then try to start it again. Bear in mind that you have probably been doing a lot of cranking and there may be petrol in the system, in the heads, etc. so ventilate and dry out first. Do NOT be tempted to try starting the car with your foot on the accelerator.

Let me know what coil type you have.