My volvo 740 had the same problem. Once the temperature reached about freezing it started fine. Turns out that Volvo has a conversion-recall-whatever for these cars. One can find it on the internet. Here's a summary I found.

Regina System No Start or Re-Start on Cold Mornings. [Tip from Bruce Young] If your car has Regina fuel injection and you have difficulties with re-starting after the car has been sitting for half an hour or so, see the Volvo TSB 23-135 from January, 1990 regarding Cold Start Problems. Here's a summary:

Below 23°F (—5°C) cold start difficulties...rich fuel mixture during cold start crank and warm-up
Before chasing this down, you can tell if this TSP has been applied or not by checking the wires at the cold start injector plug. First, peel back the rubber boot. If the 2 connected wires are Gray-Black and Blue-Green, the TSP has NOT been applied. If the wires are Gray-Black and any other color (with Blue-Green cut off and taped back -- or removed --) the TSB HAS BEEN applied. NOTE: This TSB rewiring will cause a permanent 3-2-1 OBD code, but no CE Light.
Background: The CSI has voltage is applied from the Radio Suppression Relay, like the regular injectors do. And is controlled on the ground side by the ECU, based on temperature. The TSB changes the CSI's voltage source to an auxilliary terminal on the starter solenoid. So the CSI now gets activated only during cold cranking, rather than as soon as the key is turned on for that 1-2 second pump buzz — and all during warm-up, till warmed above the cold start temp criteria