Air Conditioning (Alfa 33 907 Series)
Fast Idle Valve Installation
April 20, 2020
20
The fast idle function is somthing of significant importance in any A/C setup. A/C operation drains around 10 to 15 HP from the engine with a noticeable power loss. Such power loss is more obvious when the engine idles and the power loss often leads to engine stalling. This idle valve keeps the idle rpm at the correct level (around 950 rpm) regadless the A/C being on or off.
The fast idle valve makes a bypass to the Auxiliary Air Valve (AAV) by allowing extra air to the intake manifold thus keeping the idle at specified rpm. It should be noted that this valve is electrically triggered and is set to operation whenever A/C compressor is turned on.
The location of installation is under the ECU bracket.
Remove three (3) screws securing ECU to bracket and corrugated sleeve
Do the same for the nuts securing bracket to chassis; there are two on the front side of the bulkhead.
Another two on the rear side of the bulkhead.
This is the fast idle connector which is integrated to the engine harness of the vehicle.
Measure the distance of the mounting bracket holes on the valve body.
Drill two holes on the ECU bracket.
The air bypass will now be created upstream the AAV. Be sure to get hold of T connectors like the one shown in the picture (2 X 16 mm & 1 X 8 mm ports).
Cut the existing hose as shown on the photo.
Restore the hose to it's original position.
We will cut the hose downstream the AAV.
This is the spot for the T connector.
Restore the hose to it's original position.
A more comprehensive view of the bypass spots upstream and downstream the AAV.
Install fast idle valve on ECU bracket.
Install 8mm vacuum hose downstream the AAV as seen on the picture (about 25 cm length).
Install 8mm vacuum hose upstream the AAV as seen on the picture (about 50 cm length).
Don?t forget to plug in the fast idle connector.
The final setup should look like that.
The factory workshop manuals show an exploded view of the fast idle valve installation.
The factory workshop manuals show an exploded view of the fast idle valve installation.