I'd very similar symptoms on my 1999 UK Turbo. Car would run perfectly then just die.

Apparently the Sigma alarm fitted to UK cars of that era can fail. There are two immobilisers, one on the ignition and one on the fuel supply.

My car was sorted by running a direct ignition fed 12V supply to the fuel pump relay, through an in line fuse. Never had another issue in over 60k miles.

You may want to fit a hidden switch on the fuel pump supply to maintain the twin immobilisers.

 

Check the easy first pal
Pump itself (run a live too it)
If it powers up then look at relay and fuse.
Good it doesn’t it’s new pump and that’s your problem

 

This.

surely if you have power at the pump but no noise of it priming it sounds like the pump is dead.

 

I'm at the limits of my limited expertise when it comes to electrics! Can you give me a step-by-step guide - if that's the culprit great, if not I've ruled it out. Thanks.

 

If you google Impreza fuel pump not working there’s loads of people with same fault pal read through,
basically you need to run a live wire to your fuel pump and see if it works,

theres alao a old fashioned way of doing it get some easy start spray it into your intake turn it over. If car try’s to start then it’s your pump, don’t try and get it to run off it just see if it fires

 

Day off so back on the case. Have taken a live feed (single wire) off the wire going to the cigarette lighter, but where on the fuel pump does it go? Do I pull the multi-pin connector on the top of the cradle and touch it to one of the pins, if so which one? Or do I need to take the pump out of the tank and connect it directly to the pump?
Thanks

 

I’ll grab multimeter and check on mine what’s live pal I’m working on it anyway 5 mins

 

Mines got a big red n black and a black rest are smaller and coloured. I’ll assume the coloured ones are for your gauge etc
Mai if it was me I’d be running a live to the red and black and see what happens,

your have to plug it in for the earth the jump the red and black wire with a live.
I could be wrong,

if you go on YouTube there’s videos off how to check them pal

 

Progress. Ran a live feed to the pump (spliced into the black/red wire for info) and the pump now primes - but primes continuously not for the usual few seconds. Actually its probably the sound of the pump running, never heard it before over the sound of the running car.
Anyway, car tries to start, splutters but won't fire up. As the battery was flat I'm having to jump it from our other car so this may be an issue, also possibly flooded from all the times I've tried to start it. Leaving it for the time being, will try again tomorrow.

 

Has you running a live to pump made any difference ?
if it has check fuses and relays mate
pull plugs and clean them anyway.

 

Yes, I can now hear the pump working, it wasn't before connecting the live. I can also hear the relay click twice. Fuses in the engine bay fuse box look fine.

 

There’s a fuse box under steering wheel as well mate that contains a fuse that can stop it running.

if pump is already primed you won’t hear it. I took a fuel line off mine pointed it into a bottle and put ignition on. To see if pump was working.

took me 2 week and trying litterally everything to work out what was wrong with it pal and that was a good couple of hours a day.
Your only saving point being there a pretty basic engine electrics wise like said there’s only 2 sensors that will stop it running anything else is simple....... say simple took me 2 week to find a 50 pence o ring!

 

I've got it started. Fearing that the engine was flooded I took the plugs out, cleaned them and left them out overnight. Also go a new battery as the old one was over 4yrs old.
Reassembled it this morning and it fired up. This is with the separate live feed to the fuel pump, without this it won't start. Does this indicate that it's the Sigma immobiliser?

NB: I can't arm the system using the keyfob, neither will it activate the central locking. I get a single 'beep' when turning the ignition on.

Thanks for the help so far.

 

I wouldn’t say it’s a alarm issue mate I’d be looking at fuses and relays.

I don’t know a right lot about the alarms immobiliser ecu side of things.
But id have thought the immobiliser would have cut ignition and starter too.

Multimeter all fuses and swap relay over with another mate if not look at immobiliser.
Mid the red led going off?

 

Update: it was the Sigma M30 immobiliser.

 

Glad you found it. It did sound really similar to my problem. Maple Leaf Subaru in Daventry sorted mine once it had been recovered.

 

Thanks, had to get a local auto electrician out who removed the unit and rejoined the wires that had originally been cut. This is just a temporary measure, a new alarm/immobiliser is being installed next week.