Checking Air Flow Sensor - Porsche 928 Workshop Manual

24
Electronic Fuel Injection 928
4. Bridge terminals 30 and 87 with an extra wire.
Fuel pump should now run.
- '-'-
5. Shut off return line of one pressure regulator with
a standard hose clamp. Fuel pressure should rise
only slightly (approx. 0.05 bar).
If pressure rises, return line of opposite pressure
regulator is clogged or pressure regulator is
defective.
Check second pressure regulator in same manner.
CHECKING AIR FLOW SENSOR
1. Pull off plugs on air flow sensor.
2. Connect ohmmeter on connections 6 and 9
Specification: 200 -400 ohms
Connections 6 and B
Specification: 130 - 260 ohms
Connections 8 and 9
Specification: 70 - 140 ohms
Connections 6 and 7
Specification: 40 - 300 ohms
Connections 7 and 8
Specification: 100 - 500 ohms
Connections 27 and 6
Specification: 2 - 3 k-ohms at 20 "C/68 OF
Note
Beginning with manufacturing date 042 (stamped
in housing of air flow sensor).
1. Pull off plugs on air flow sensor.
2. Connect ohmmeter on connections 6 and 9.
Specification: 400 -BOO ohms
Connections 6 and 8
Specification: 160 - 520 ohms
Connections 8 and 9
Specification: 140 - 280 ohms
Connections 6 and 7
Specification. 80 - 600 ohms
Connections 7 and 8
Specification: 200 - 1000 ohms
Connections 27 and 6
Specification: 4 - 6 k-ohms at 20 "C/68 "F
l
24-20
Checking Pressure Regulator VI, 1982 - Printed in Germany
Checking Air Flow Sensor