Help!! I'm at my wits ends with this one!
So here goes. After owning a few gen 2 9-3's (all 1.9 TDi's) I've bought a really nice looking gen 2 convertible with same engine.
It was bought on fleaBay as Spares or Repair as had blocked DPF and was on limp mode. Not too far away, from old chap that only ever used it for short local trips. Being somewhat handy mechanically (depends who you ask I guess) I thought 'Just needs a good run down Motorway, and will be as good as new when bring her home to meet her sisters!'. But not being a pessimist, but an optimist with experience, I brought the tools with to loosen/disconnect flexi in case it's really bad and allow some gas-flow out. His local garage beat me to it and they undid the thing completely - a good start!
Oh no. Thing was SO bad I had to pull in 4 miles down the road and get RAC to tow me home after they couldn't get the thing to force regenerate. Following morning had the DPF off, blown with air, refitted and once could rev, took her up and down the road for over 60 miles, being able to rev it up 200-250 rpm gradually. It now reaches the red line no problem. It also went to London and back (from Somerset) no problems, albeit a lack of power and still with 'Limited Performance' on dash and with diesel cleaner in tank . Was much better after but still not right. Really bad MPG as well!
Got friend with Vaux/OpCOM to plug it in and it came up with 'P1125-08 Throttle Actuator Feedback Circuit'. So got another throttle (ahem, it's a diesel...) but no change. Also Injector Values were all over the place so replaced the x2 worst with a pair from a car (2005 1.9 saloon) in the local breakers. All that did was make things worse! Lots of black smoke and miss-fire! Took it to my local garage to be plugged in. They came back with DPF and MAF. Put a good MAF on it. Changed inlet manifold and blanked swirl flaps (throttle was SO gummed up i reckoned the rest of the inlet system would be too!). Cleaned MAP and blocked EGR with proper plate at its inlet. Since went back to original injectors. Better, but still miss-firing (at 1.5k-up rpm). When inlet manifold was refitted and car started for first time. within a minute of running the temp gauge shot up to 130 deg c and fans came on

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This is where the plot thickens! Read on! Fiddled with connector and temp gauge was good again.
Had my friend come over again with OpCOM, we took it for a spin to warm her up. all good (apart from horrid running). Plugged in, and 'Throttle Actuator...' again... went to motor to fiddle with connector in case it wasn't seated (new throttle unit) and temp gauge falls down to nothing. Reading -40 deg!!!
Had a squint at wires and the rubber sheathing were
COMPLETELY worn!!! on both throttle AND green Temp sensor. (New to forum and can't figure out how to upload pics!)
It looks like there was a chemical spill of some description in that area as I've [b]NEVER seem anything like it. Rubber covers have just crumbled in my hands leaving bare wires!![/b]

Shame i can't upload pics - It's a horror story! RESULT!! I thought. Just replace this bit of wiring and have a stonking, sorted car!
Made sure bad wires didn't go any further up my loom. Went to breakers this morning. Snipped nice long tailed two offending connectors, and drove home with a smug 'Gottcha' smile on my mug. Did a nice job of rewiring the piece (proper crimps, test strength and integrity of join, heatshrink and continuity test. I can't profess to be able to do much in life, but I know how to wire a loom).
New plugs connected. Engine started.
Temp gauge needle at nothing. my cheapo diagnostics reading -40 deg and P0115 Engine Coolant Temp Sensor 1 Circuit. Fans straight on!
Did some digging on line, and from what I can make out it shorted (no surprise) and frazzled the ECU
So. I can get another ECU from breakers (not sure if part numbers are identical though), BUT wanted to know, Is the original ECU ducked or can it be reflashed/rebooted? Battery is disconnected overnight (I'm stupid and desperate enough to try it...). Or if I get a replacement ECU does it need to be matched to the car? Seeing as it only controls the engine parameters (it will never be THAT simple I guess). If it needs wee. Will a Vauxhall (GM) garage be able to do it?
Any help would be appreciated. I have NEVER in my LIFE struggled SO much to get a car going right. And it STILL isn't. My next step is a BIG hammer, screaming at it or collapsing into a fetal position on the floor in hysteria

It will be as much use as everything I've done up to now.
HELP! PLEASE!!!
Can't PM people back as new member but please text or call me on 07932095874 if you can give any advice