Killed something in my electrics - 3 second cranking limit

[cliomtb]

My 182 has been running fine until today. When I tried to start it this morning, the starter didn't turn, followed by the sound of one or more relays switching at high frequency. I suspected a loose battery connection and sure enough, the earth cable was loose. I tightened up the cable and tried to start it again, but it will only crank for 3 seconds and then stops. There is not any hint that it is even trying to fire. I'm guessing when the earth cable was loose, some large current has taken a different route to ground and fried something.

Full symptoms, starting from being outside the car, doors shut and locked:

1. Immobiliser light flashing at 1 Hz
2. Press button on key
3. Car unlocks
4. Immobiliser light still flashing at 1 Hz
5. Open door, get in car, close door
6. Insert key
7. Immobiliser light still flashing at 1 Hz
8. Turn key all the way
9. Immobiliser light solid
10. Engine cranks healthily for 3 seconds
11. Release key
12. Immobiliser light out for approx 5 seconds
13. Immobiliser light resumes flashing at 1 Hz

The immobiliser light never flashes at a faster rate

So I'm thinking I killed something when the battery cable was loose, or the immobiliser has got into a weird state and I need to reset it, or I've a bad earth somewhere.

I've cleaned up all the fuses, relay contacts and the white plug under the bonnet. I've checked the 3 smaller relays by swapping them around.

What is enforcing the 3 second cranking limit? The immobiliser? The ECU? Why?

Any pointers will be very much appreciated

Thanks!

 

[Louis]

Ensure earths are tight.
Turn the key all the way and hold it for 5 mins there, without starting the car. Then off and on again

 

[cliomtb]

@Louis Thank you very much

Turning it on again didn't work first time, but turning the key a 2nd time (without another 5 minutes), and all is back to normal.

What did it actually do ?!?

 

[Louis]

@Louis Thank you very much

Turning it on again didn't work first time, but turning the key a 2nd time (without another 5 minutes), and all is back to normal.

What did it actually do ?!?

Immobiliser issue. Happens when you have the earth loose to the battery. Think it almost loses connection to the key so it doesnt recognise it.

I've had it before and had to walk to work, then tried that when I got home and fired right up 😂