Elevrovalves removed

My '82 308 GTSi
One solenoid works the egr
One solenoid works the air injection
One solenoid works the fast idle air valve

I have the first two disconnected and removed. The third one I have in service. I limit the air valve by a tab I made by the actuation arm so the idle does not race.

 

I can understand the cold light not working. The alt light on and running rough could be low voltage to the system causing low spark or havoc with the digiplex. Put a volt meter on it.

 

Yes. When cold, the water thermoswitch is open = the voltage on the SN (pink-black) wire goes to +12V (by being connected to the R, red, wires on the electrovalves via the coils inside the electrovalves) = "tells" the DigiPlexes "I'm cold - use the cold map"' and turns "on" the cold-running light in the dash. When the coolant heats up and the water thermoswitch closes = the SN wires goes to ground (two of the electrovalves energize), the dash light goes "off", and the DigiPlexes know to use the "warm" map.

When you unplug both electrovalves that have a R and SN wire = you remove the +12V source to the SN wire = DigiPlexes always think "warm".

That said, I've got to agree with Wayne's point -- although you need to be careful with the unplugged harness ends to not let the terminals touch anything.

 

Correct, you can't use a direct short (nor a fuse) as the current would be way too high when the water thermoswitch closes. Measure the resistance of the coil inside the electrovalve (IIRC, it might be something like 150 Ohms) and then buy a similar value resistor that can handle the power (maybe 2W?) and use it to connect the R wire to the SN wire of one of the electrovalve harness connectors. The calculations would be something like:

V = I * R (for 12V and 150 Ohms, I = .080A)

Power = V * I (for 12V and .08A = .96W -- therefore, use maybe 2W capacity for margin)

Of course, if the resistance of the electrovalve coil is something other than ~150 Ohms, just redo the calculations to get the power rating needed for the resistor.

 

maybe you can post some pictures ?

 

One other thought here is that the wire in the electrovalve coil may heat up slightly when in use with a real current and have a higher functional resistance (when you measure the resistance of the coil with the multimeter, it is done at a very low current). Just mentioning this as it would be best to use as large a resistance value as possible to minimize the power wasted (and the power rating/size of the resistor). If you place 12V on the electrovalve coil and measure the current, the functional resistance could be calculated -- just a thought...

 

this would be the easiest way to disable the fast-idle-system (and is what most people do)
in this case you would loose the yellow cold-light function in the dash

so instead of jumping the switch, you can leave it connected and just swap the vacuum hose on the cold air valve from the electrovalve directly to manifold vacuum -
this way you maintain the yellow cold-light function in the dash

no, not needed at all
I have thrown out the catalytic converters and de-activated this fast-idle-system 10 years and 40K miles ago ...
and I can tell you from first hand experience that there is absolute no disadvantage by doing this

if you keep the fast idle sytem and you think environmental, yes (heating up the cats faster, less emission etc.)

if you remove the fast idle system, no

the cold-start air valve concept was only added for U.S. emissions compliance
to disable it, will not harm your engine - no other Ferraris of this era had this modification in any other world markets
.
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