Cold Start Lean

[markoc85]

Hi, my car has a 1994 3sfe, and it doesn't like starting when cold.

To start it, I have to pop off the air filter pipe and jam a drink bottle in beside the butterfly to act as a choke, then it starts fine and I pull the bottle out and drive away - no worries!

The idle speed control valve works, so does the aircon idle valve, but whether they work properly I'm not sure. I'm not aware of any other mechanisms acting as a choke? Fuel filter and injectors are fine I think because motor runs fine once its started. No engine warning lights on dash have come on.

If I block the throttle butterfly completely with the drink bottle, the engine struggles but doesn't stop, still runs at about 500rpm. Is this normal or do you think theres an air leak causing it to run too lean for starting? Where should I look? Any other reasons for this cold start problem?

Ps I've tried the usual expletives and beating my wife, they didn't work, any other suggestions or expletives to try much appreciated. Just kidding :)