Very disappointed, am I loosing time on my car? Options

[VINCE]

I feel very bad tonight. I bought my first 914 one month ago. I am working on it every evening since one month and sometimes until midnight (it is very cold in my garage)... (IMG:style_emoticons/default/sad.gif)

I think I am loosing time. The more I do, the worst it is. The L-jetronic make me crazy (the 914 is a stock 1.8L from 75).
For example, the engine was runnig two days ago (only on idle because if I tried to open throttle the engine was dying): my cold start valve was OK. And tonight, the cold start valve is not working anymore!!! What is wrong? I don't understand.
It seems I have fuel pressure because when I disconnect the fuel pressure regulator I see a fuel spray. I don't understand how this cold start valve is working. Wich sensor is related to the cold start valve?
It is the same thing for the 4 other injectors... I have no fuel spray.

I have tested (according the Haynes diagnostic method) the air intake sensor
and the throttle body and they are OK.
The only thing I am dubious is the temperature sensor II. Where is it? How I disconect it?

I really need to fix it quickly because it is my daily driver. Should I carb? With what carbs? I need the car run in winter but I don't need more hp. Is it possible to find and adapt 40 PDSI? Can I find manifold and throttle linkage for 40PDSI quickly?
Should I try to continue fix my L-Jetronic?
Should I buy an other car?

Please, help me. I am sure some of you have been in the same situation.

Thanks

Vince