Ferrari Mailing List: Re: 328 reluctant dead cold start

[Paul Bennett (pbennett]

> ... the Thermal Time Switch sensor on the manifold senses the block temp, and 
> injects fuel into the
> cylinders until the car warms up. If it isn't working probably, it's a real
> bitch starting when cold and will run rough for a while until the block
> heats up. I guess this is also referring to the cold start sensor/injector
> set-up.
>    
You may be on the right track.  But, the thermo-time switch doesn't 
sense temperature, it uses block heat to warm a bimetalic strip, opening 
up the circuit, disabling the circuit when engine has warmed.  The 
function of the TTS is to completing the circuit to the cold start 
injector ONLY during cranking.  When the TTS goes bad in their normal 
fashion, it stays closed, you have 'warm start issues' i.e. flooding a 
hot engine with fuel through the cold start injector.  Using a test 
light or voltmeter on the cold start injector connector, easily 
accessible, can prove this circuit quickly but unless you are ingenious 
it requires 2 people, one turning key to 'Start' and other observing the 
test light.  If you have no voltage, know that some cars have a separate 
hard to find semi hidden fuse in this circuit.  You could even have a 
wire come off the TTS.

There should be a check valve between fuel pump and accumulator.  These 
hold fuel pressure for about a day.  Over that, it takes longer to build 
fuel pressure before a start.

Your situation of engine swap leaves a mystery of how the car is wired 
so a solution to 30 seconds of cranking is further complicated.  The 
cold start injector requires 2 relays, not found on pre injection cars 
(i.e. 1977 308)