Has anyone tried this?

I made a small jumper wire to bypass mine also,Here in FL you really don't need it in the summer.I do let the car idle a little longer to come up to temp before heading out.

 

The cold start valve, when working correctly, only injects fuel during CRANKING. Not during idling, not during warm-up. Disconnecting it will have no effect on the idle speed.

Just to make sure we're talking about the same thing... I'm referring to the "9th injector." The one on the intake plenum that is electrically operated (as opposed to the mechanical fuel injectors).

The cold start valve/injector on my 328 has been disconnected more than 10 years. No problems. Perhaps in a REALLY cold climate it might be needed.

If your idle speed is too high and you have no vacuum leaks then you can insert a metal object in the air line from the AAV to lower the amount of air getting to the engine. Say, some type of round object with a hole in the middle. If the idle speed becomes too low then drill the hole bigger.

I have a Euro spec. 328 and you have a 308 (U.S. spec. I assume) so there may be some factors I'm over looking here (added stuff/parts on the U.S. versions).

Unfortunately, I think that a cold idle that is really quite high (even when everything is working correctly-no faults) is designed to get the catalytic converter(s) up to temperature as quickly as possible and "mechanical sympathy" for the cold engine with cold oil takes a back seat to this.

 

He's talking about the "cold start air valve" (a US version only item), not the "cold start valve" (AKA cold start injector).

Tom -- Do a search on "cold start air valve RPM" for prior discussion. Many do disable it completely, but (as you'll see in those prior threads) you can also add a simple restriction to reduce the RPM increase to a more reasonable value and keep the system looking "stock".

 

Is that something different from the AAV?

 

Yes, it's a device that works in parallel to the AAV in the same fashion (it routes extra air around the throttle plate, raising the cold-running RPM, when the coolant thermoswitch is cold/open) -- be thankful you don't have one
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The "simple" pipe at the bottom of this jpeg is what conveys the air flowing thru the AAV on a euro version. For the US system, they "T'ed" in the cold start air valve so the same pipe carries the air flowing thru the AAV and the cold start air valve:
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Now I'm confused... why would there be a second device in parallel with the AAV to route additional air into the engine? Do they function differently or at different times?

 

It's primary function is to raise the cold-running RPM (even more than just the AAV) to heat up the cats more quickly and reduce emissions. They operate at roughly the same time, but in slightly different manners -- the AAV closes slowly as it absorbs heat from its internal heater and/or the engine, The cold start air valve is fully open when the coolant thermoswitch is open (cold), and fully closed when the coolant thermoswitch closes (maybe ~150 deg F coolant temp).

 

Yuck. Yes! I'm glad I don't have one. If I had a car like that I would do my utmost to reduce excessive "plumbing." Though, I suppose that might be an emissions/inspection issue in some locations.

 

In the interest of losing some plumbing under the hood I lost the AAV and kept the cold start valve. I did put a restrictor in the line to keep the intended 3000+ rpm warmup to something closer to 1800. And then I moved off the side of the engine and out of the way. All that extra stuff hides the beautiful engine!