Emission Testing, RPM Signal

[How-To Doc]

Emission Testing, RPM Signal

Author: Subaru

NUMBER: 11-42-93

DATE: 06-03-93

APPLICABILITY
ALL SVX, LEGACY AND IMPREZA MODELS

SUBJECT:
ENGINE REVOLUTION REFERENCE SIGNAL FOR EMISSIONS TESTING

THIS BULLETIN IS FOR INFORMATION ONLY

SVX Procedure:

Passenger vehicle emissions testing and certification require a tach or rpm signal from the secondary ignition system. The DIS type or distributorless ignition system used on the SVX does not use conventional ignition wires to link the coil to the spark plugs. It will be necessary to perform the following procedure to obtain the proper signal:

1) Locate one of the six individual ignition coils, remove the retaining bolt and disconnect the coil from the spark plug.
2) Temporarily install an original equipment Legacy spark plug wire between the coil and the spark plug.
3) Attach the emission machine tach sensing pickup.
Note: Some emission testing machines do not require this procedure. The Tach sensing pickup can be connected to the wires from the ignitor to the coil: Example: Allen model 42-100.

Legacy and Impreza Procedure:

The DIS system on both Legacy and Impreza models use conventional high tension ignition wires which can be used to obtain an rpm signal.

NOTE: The signal outputted by the coil on these models with DIS will be approximately twice the engine rpm because the spark plug is fired on both the compression and exhaust strokes. Most emission testing machines have a mode that will divide the rpm by two. Check with your emission machine manufacturer.


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