Car not igniting 20V Omex ECU

[Jezza_hr]

I've run into a problem this evening being unable to call on Omex for help I thought I'd call on you guys.

I've established one thing, it's the coil pack that is not getting a ground or 12v supply as I managed to get it started using some wire coming directly from the battery, but this only worked temporarily until the wires melted. Going back to the ECU I can't see any issues with the wire itself, what could I be missing?

If it helps I was changing the light switch when this problem started, is there anything around there that could cause issue with ignition? The ECU is working fine, so I'm really baffled.

[Ivan141]

Melting wires?? Might be a short circuit somewhere, make sure you check your fuses.
Your coil pack is supposed to get a constant 12v from the ignition switch, the ecu switches the other side of the coil to ground to fire it. Sounds like you are missing 12v, which is likely a wiring/fuse issue.

[jondee86]

ECU and ignition usually are both energised from the keyswitch, usually
with the ignition power coming from the battery via a relay. If you could
get it to run by taking battery power directly to the coil positive, then it
would seem that you have leakage to ground on the power supply side.
Either between the keyswitch and the relay, or between the relay and the
coil. Melting the wire indicates a high current, more than the coil would
draw on its own. So look for a hot wire (literally) when the key in ON.

Oh... and smoke

Cheers... jondee86

[Jezza_hr]

I've looked back down the wire and I can't see it grounding anywhere, I'll have a harder look in the morning to see what I can find. The ECU clicks on with the ignition and I'm getting a reading back to the laptop to say that that it's getting info from the crank sensor it's just not sending anything to the coil pack (which generally isn't fused).

Maybe, it's something near the barrel as I had to move some of the dash down to change that light switch, it sounds like the only likely area a culprit could form but I would have thought because the ECU is getting power then it should feed that power to the coil? since the 3 wires (ign1, ign2 and 12V) come off the ECU itself

[jondee86]

It would be unusual to have the ignition power supply coming from the
ECU. As said above, the power usually comes from a separate circuit, that
bypasses the ECU. In the factory wiring it comes from the keyswitch.

The ECU pulls the coils to ground to fire them, but if there is not 12V on
the positive side of the coils.... then there will be no spark. Check and
see if the 12V for the coil really does come from the ECU, or from some
place else.

Cheers... jondee86

[Jezza_hr]

To give you an idea, I'm using a wasted spark setup much like this



But I do believe the ECU supplies the feed directly as comes off the loom.

[Jezza_hr]

Aha, I've just had a thought, the STOP fuse has relation to ECU power and that could have tripped when I was changing the light switch and the only reason the ECU is working is because it's using the ignition switch power to keep everything else running but it's not using a constant battery feed. This could make sense

EDIT: I was right, I just went out and checked it (at 3am) to discover my brake lights don't work, upon checking the fuse it has blown simple fix ahoy

[jondee86]

There is probably a good reason for that fuse stopping the ignition from
working, but I'll leave that to you work out

Drive and enjoy....

Cheers... jondee86

[Jezza_hr]

I worked that part out, I never thought to check it though being as stupid as I am

[Jezza_hr]

I went ahead and replaced that fuse, however I seem to have a new problem in the ways of cylinders 2 and 3 not firing, as if the ECU is not grounding them or the (Sagem) coilpack is permitting a fault. Unfortunately I won't get a chance to know for sure until I speak with Omex on Monday as they're probably going to be able to diagnose it fully.