Alfa Pages

bobbber

I've noticed this little gem on the Jetronic Injection diagrams (marked as Number 2):

The key says 'Extra Air Solenoid Valve' - does anyone know what this is, and/or what it does?!?!?!

Thanks!

Bob
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Fiat Bravo 165 Sport

Ben_nz · Posted: Thu Jul 29, 2004 12:29 pm Post subject:

Ah, the Extra Air Solenoid Valve. As you can see, it connects to the intake manifold after the airflow meter, and allows extra air to be drawn in from the engine bay. With the valve open, some of the airflow into the engine bypasses the airflow meter, fooling the ECU into delivering less fuel than required.
Alfa Romeo were struggling financially in the early 90s, so they designed this valve to open in the event that your car was running too well. This would bring in more money by keeping the service departments busy repairing engine damage caused by detonation or overheating.. Wink

bobbber · Posted: Thu Jul 29, 2004 12:39 pm Post subject:

What really causes the valve to open/close?!
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Fiat Bravo 165 Sport

Lon · Alfasud Joined: 28 Mar 2003 Posts: 29

If i'm right it's only open when the engine is idle
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Registro Trentatre: http://www.alfaromeo33.nl

Alfa 33 1.7 S 16v QV '92

Matt Stolton · Posted: Thu Jul 29, 2004 4:48 pm Post subject: Idle control valve surely....

It looks to me like it is the idle control valve, which is physically located on the front of the plenum, between it and the radiator. At least that is what it is on the 16V.

On the 16V, because the butterflies in the throttle bodies are closed after the AFM, at idle, no air can get into the chambers to burn the fuel. To get around this the ECU opens this valve which flows air from the plenum to a plastic splitter device under the plenum, which has four pipes routing the air into the throttle bodies after the butterflies, to mix with the fuel from the injectors. The ECU can regulate this valve to help play (piss about with) with idle speed /mixture etc.

However, that diagram appears to be of an 8V i.e. engine/plenum, but I would expect it does a similar job, but due to the lack of 4 butterflies, flows air into the plenum, rather than out, and then straight onto the injectors and combustion chamber.

It must just be some device to add extra air, as dictated by ECU, and I presume it is a magneticly driven valve, commonly known as a solenoid valve. As per ronseal man, it does exactly what it says on the tin.
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Regards

Matt

Ex Alfa 33 'GTA' (P4 with Knobs On)
Now cruising in a 166 3.2 Ti!!