9000 L4-1985cc 2.0L DOHC Turbo EFI (1987)
Air Flow Meter/Sensor: Adjustments
Checking and Adjusting the Pulse Ratio
This adjustment provides a reference point for the LH system and does not affect drivability.
Calibration should only be carried out when engine performance has changed as the result of major work carried out on it.
1 Connect pulse meter 83 97 597 to the test point in the TSI socket, located in the engine bay on the left-hand side. Use adapter cable 83 94 132.
Alternatively, an ISAT scan tool can be used in conjunction with test cable 86 10 784.
2 Start the engine and warm it up. When the basic setting is correct, the pointer needle will oscillate for an equally long time at both ends of the
scale.
Note: The pointer needle will move slowly and may occasionally stop. It moves much more slowly than when testing the CI system.
3 If adjustment proves necessary, turn the adjusting screw as follows:
a. If the pointer needle stops at full scale deflection or remains most of the time in the right- hand portion of the scale, turn the screw
anticlockwise until the it remains an equally long time at both ends of the scale.
b. If the pointer needle remains in the low end of the scale, turn the screw clockwise until it spends an equally long time at both ends of the scale.
4 If the pulse ratio is above 6% and cannot be adjusted, switch off the engine, unplug the mass air flow sensor connector and connect a multi- meter
to mass air flow sensor pins:
3 and 6 (-M1987 fuel injection engine, -M1988 turbo engine)
2 and 6 (M1988- fuel injection engine, M1989- turbo engine)
Turn the adjusting screw until 380 ohms is obtained.
If this reading cannot be obtained, change the mass air flow sensor.
When the right reading (380 ohms) is obtained, plug in the mass air flow sensor connector. Start the engine and warm it up.
Check and adjust additionally until the correct pulse ratio is obtained. If the pulse ratio still cannot be adjusted, check the mass air flow sensor
wiring and electrical connections.
