After messing with the ECU last week the Z is dead. I have unplugged the ECU and tried turning the key but it's exactly the same - dash lights come on as normal but nothing fires/turns over when I turn the key.

I was told that even without the ECU the fans should come on and the engine will crank. It's not doing this. Any ideas?

Need to get it sorted this weekend.

 

Some ideas...Try checking all fuses. I assume the starter motor etc is working and the problem is just ignition related. Check your relays. Check all your connections. Do a diagnostics. Check the snap connector for the ecu is really connected properly. Check ECU powewr supply and ground circuit.I assume your battery is charged. Is an immobiliser fitted and OK? Check for a faulty earth somewhere.Check the power transistor unit on the front of the engine. Check sensors and connections e.g. TPS Hope it helps.

If it's not even cranking then it could be the starter inhibitor circuit - if an auto then it has to be in park, manual has a relay in the n/s wheel arch I *think*..

 

sorry, brain dead from looking at this loom for too long.. back off out now to cut some wires..

It's all happened since swapping the ECU so it must be:

A, ECU gone faulty - but should still crank without it and it doesn't so points to fault elsewhere.

B, A wire has come loose on the ECU harness - Can't see one but there are lots of taped up joints down there, possibly to the immobiliser.

C, A fuse has blown somewhere which is involved with the starter/immobiliser circuit. Checked under bonnet and a few which look likely in interior fuse box (what a pain that is!)

 

Anything else seems too much of a coincidence to have blown elsewhere on the car.

 

I'm checking all the taped up joints... fun.

 

The imobiliser seems to work OK.

It has a light on the dash which goes off as normal when deactivated but if the circuit it enables is broken I don't suppose it would show up.

 

MAC1 came over yesterday and we swapped ECU's. Many thanks.

Mine worked in his but his in my Z still dead.

Spent all day tracing wires and found a break in the starter inhibitor circuit for the auto box where my alarm/immobiliser had joined into it.

Thanks Aaron, I would never have thought of it.