The immobiliser relay is behind the plastic bulkhead inside the cabin behind the pax seat - did he remove that big piece of plastic to gain access? If not, I don't know how he can know the immobiliser isn't there. It doesn't look like a normal automotive relay, though, just a box with about 20 (probably) black wires running into it.
[edited to add, at least this is where it was on the one S2 I ever saw it on - there might be a loom change that relocated it?]
The rough running is just the ECU and will go away once it's done enough miles and the battery hasn't gone flat in the meanwhile (the ECU remembers stuff and this gets forgotten when the battery is disconnected or goes flat).
Even if it doesn't go away, the rough running has nothing to do with the non start which is either an immobiliser problem or perhaps a bad earth issue.
If neither the starter nor the fuel pump priming works then it is an immobiliser issue pound to a penny. There is the possibility of a MFRU failure too, but less likely to cause both these symptoms together so reliably.
To be sure, turn the ignition off, remove key and wait for 30 seconds or so (until the red light starts to blink on the dash board). Now do this in the sequence I have written:
Press the fob to turn off the blinking alarm/immob light.
Insert key and turn to run position (i.e. just before the crank position).
You should hear a relay click and then 3-5 seconds later you should hear a second, quieter relay clonk. If the immobiliser is working OK you won't hear the relay clonks because the fuel pump priming will be too loud.
If you hear the fuel pump, the immobiliser is (partially) working.
If you don't hear the fuel pump but you do hear the relays clonk twice then the immobiliser is probably at fault.
If you don't hear the relays try to repeat the experiment with somebody else operating the immob fob and key whilst you have your ear close to (but not inside
) the engine bay. This is because the relay sounds might be too quiet to hear, depending on ambient noise.
If you really don't hear the relays clonk then the MFRU might be at fault or the two fuses next to the ECU.
If you do hear the relays clonk but no fuel pump prime or cranking then try this:
Car in neutral, handbrake on, ignition off (key can be in your pocket if you like).
Identify the starter and look at it from the back of the starter (i.e. with you standing on the kerb side looking into the engine bay).
Remove the wire from the spade terminal at the bottom of the starter back plate (6 o'clock if it were a clock face).
Get a length of wire and touch it from the spade terminal sticking out the back of the starter to the stud with a couple of fat wires on it at 3 o'clock. The starter should crank the engine over at this point, regardless of immobiliser setting.
Next repeat this with the ignition on and immob cleared. It probably won't start up because the fuel pump isn't running, but worth trying.
Now we can prove it's the immobiliser by removing the plastic cover behind the seats to reveal the immobiliser relay and temporarily bypass it with two bits of wire. If you want to do that, let me know ...
