Trouble starting a Mk1 (immobiliser?)

[berlin]

I've had problems for a while now, where the immobiliser won't properly turn off when I click the central locking, but I've always found it could be started by just revving it a bit as it was turning over.

But earlier today after I had it parked up in town, so it was starting from cold, it just wouldn't start up. The interior light was coming on and the flashing imobiliser light going out when I clicked the locking, so I don't know whether this is problem with the imobiliser or not.
The starter motor was working, but it just wouldn't come to life. I kept trying for a bit, then gave it a rest and walked to Tesco's to buy a Danish to cheer me up. Came back, same problem, but then it just kind of 'stumbled' into life. As in I was about to turn it off again when it just started turning over. Gave it a few revs and it comes to life.

Once it was warm there were no more problems, and it'd happily idle and everything else. But then a minute ago, I had the same problem with it sitting on my drive (which is worrying as I don't have homestart) again from cold.

So what's your thinking on this? Immobiliser or not? Oh can anyone recommend a good (read:cheap) garage in Wiltshire way?

Cheers!

 

[berlin]

Since then it's started perfectly a couple of times from cold, and again has done it's little act again. So I don't know what to think.

Surely someone must have even the wildest thought about this... or maybe even an interesting story about horses. Seriously I'd appreciate anything.

 

[Chris_H]

its not the immobiliser, that should have been fairly obvious by the fact it would start with a bit of throttle eh!

The fact it goes with throttle would point me to the coolant temp sender.

 

[fastwunz]

it may sound silly but have you checked your sprak plugs? I had a similar problem with my valver and it was down to oil on the sparks - this can stop them spraking and fireing the engine into life.

Like i said, it may sound a little obvious but have a check anyway. Appart from that, i would suggest looking at your coolant temp sensor which is a common problem with these. They often read the temp wrong and cause idling problems when cold - mine started just stalling my engine completely whenever the revs dropped to idle point which believe me - wasnt fun