'85 ur-q Cold Start Problem (long)

["Mike Hopton" <mike@genesis-microchip.on.ca>]

     Hoping someone may be able to shed some light on the following cold start 
     problem.
     
     If I leave the car and it gets too cold (~anywhere below 0C) the car 
     becomes very difficult to start and when it does start I need to open the 
     throttle completely to get the car to keep running. The throttle has to be 
     held wide open for a while, and the car usually dies four or five times and 
     has to be cranked over. The problem is temperature dependent getting worse 
     as the temperature gets colder, be interesting to see if it starts tonight, 
     I'd like to get home.... Once running it idles and accelerates well.
     
     So far I have checked all the fuses, cleaned up the contacts for the ECU, 
     and pulled the cold start injector and plugs. The cold start injector is 
     working okay (verified fuel squirt into jar test). The plugs were black 
     (carbon build up, all plugs the same) this is probably a symptom of the 
     problem? After cleaning the plugs and putting the cold start injector back 
     there was no improvement. 
     
     I also cleaned a ground contact at the back of the block and fixed a broken 
     ground contact at the front of the block. Hey presto, 9.00p.m. last night 
     the car started perfectly and idled as normal, so I assumed the problem was 
     fixed.... Well, it started fine this morning (quite a mild night/garaged) 
     and I got to work. After sitting in the car park for 4 hours I go out and 
     try and start it. It's back to it's usual, all the symptoms are the same as 
     before. Once it's running it's fine.
     
     Apart from hoping the wind dies down and the temperature doesn't drop too 
     much. Can anyone recommend things too look at. Does this sound like the 
     warm up regulator? Personnaly I think it's electrical. Any clues to where I 
     should look next would be apprecaited. Where is the fuel punp relay in an 
     '85 TQC (Glen?)? After cranking I hear the FP buzzing for a few seconds 
     then it switches off, but it doesn't buzz with the ignition is turned on - 
     Is this right?
     
     Sorry for the length, thanks and regards, Mike