OK update - the immobiliser cutting in uncontrollably/when not wanted was getting a bit much - from once or twice in the last week to almost every start up in the last couple of days, and it was somehow also causing the battery to go flat really fast.
The wife got caught out again yesterday on the school run - exactly the same spot, with exactly the same RAC bloke, so that was the last straw...
If you've only read about "taking the dash out" to do the spider bypass, then it's built up to be this huge job that takes hours and hours and I really wasn't looking forward to it. Back in reality, it took me 15 minutes to get it out and get to the spider! It was so fast in fact that I thought to myself 'that's obviously not the spider, because it takes another hour or so to get to it'...
I tried the bypass plug/cable and it fired up straight away without fail, so I took the spider/immob unit out and it smelled pretty burned out, so I wopped it out onto the desk and set to reflowing all the solder joints on the PCB.
Plugged it in and bosh - it fires up straight away
Now, the untold story here is that my Disco has
always been a slow and sluggish starter, especially in the mornings. A year or two back I replaced the battery (when it died) with a 1000CCA Enduroline CXV-X beast of a battery, and it had the engine roaring into life, but that sterling morning performance (oo er missus) gradually faded back to the norm of slow spinning over and catching/firing up after 10 seconds or so.
So back to the current situation where I've fitted an old (and pretty weedy) battery as a stop gap because the 1000CCA one is faulty, and the last 2 weeks have seen the engine
really struggling to start - more so than normal, and getting to the point where I would wonder if it was going to start before the battery went flat. Yesterday the battery wasn't easily starting the car at all - I thought I'd need to charge it overnight just to be able to get another start out of it this morning, so imagine my surprise when my old crappy and leaking 7-8 year old temporary battery started the 300tdi like it was brand new! It wasn't just a fast start, it was less than 1 second. Infact I'd say it was within the first turn of the engine!!
I knew the immobiliser was a common problem for starting, but I never expected that it would be the root cause of
all of the poor start up performance since I've had it.
While the middle of the dash was out I fixed a load of other niggles like the heater switch that had almost self destructed and melted into a solid blob and stopped working, I replaced the clock and instrument lights, lubed all the heater control cables, mechanism and mechanical dial controls, and lubed up all the slidey things in the lower dash which are all now nice to use again.
So the moral of the story is - Don't expect every job to be as bad as they say, and if your Disco is a poor start like mine - get the spider bypass or repair your immobiliser!
Thanks for all the help and advice chaps...
