Cold Start Diagnosis For 1981-83 900, 900S, Turbo

COLD START COMPLAINT DIAGNOSIS (See p.7 for Driveaway Complaint)

Model Years: 1981-83 900, 900S, Turbo (see p. 3 for 1984-85 cars)

Symptoms: Extreme difficulty in starting a cold engine; stalls repeatedly after start up.

Diagnostic and Repair Details:

1. Check the following C.I components which, if out of adjustment, can cause difficulty in starting and driving. The engine must be cold.



- Check the rest position of the air flow sensor plate (ignition, fuel pump off). The upper edge of the sensor plate should be level with the bottom edge of the venturi. This is the highest permissible position of the sensor plate. A position slightly below the lower edge of the venturi (0.020", 0.5 mm) is also permissible (see drawing).

The measurements should be taken from the middle of the lever. The rest position can be adjusted by bending the clip (A, see drawing) for the
spring loaded arm on the underside of the air flow sensor. To adjust the sensor plate the air flow sensor assembly must be dismantled.

- Check for intake air leaks between the air flow sensor and the engine.

- Check that the auxiliary air valve is open (cold engine only).



2. Install Saab C.I.S. pressure test equipment (P/N 83-92-516).

- Measure and note ambient temperature.

- Remove fuel pump relay, unplug wire connector at control pressure regulator (warm-up regulator) and unplug wire connector at the auxiliary air valve.

- Connect a jumper wire from terminal
30 and 87 of the fuel pump relay socket.

Measure the line pressure. Adjust if out of specification.*






Line Pressure Checking Value, 1981 4.5-5.2 bar
Line Pressure Checking Value, 1982-83 4.7-5.4 bar

Line Pressure Setting Value, 1981 4.7-4.9 bar
Line Pressure Setting Value, 1982-83 4.9-5.2 bar
- Measure the cold control pressure and compare your readings with the graph at the right. If not within specification, replace the control pressure regulator (a more detailed chart is attached to the end of this S.I.).*

- Control Pressure Regulator P/N 75-15-554


3. Check the Cold Start Function

- Plug in the fuel pump relay and re-connect the wires at the control pressure regulator and auxiliary air valve.



- Verify cold start injector function by removing the injector and checking the spray pattern. Observe the following steps:

a. If practical, move the car outside away from sparks and flame and have a fire extinguisher handy. YOU ARE DEALING WITH AN EXTREMELY EXPLOSIVE MIXTURE!

b. Disable the ignition by disconnecting the primary harness plug from the base of the distributor.

c. Remove the cold start injector from the intake manifold, aim it into a container and crank the engine over for a few seconds. With a cold engine (below 113~F) the injector should spray a finely atomized mist of fuel and close without leaking as soon as you stop cranking. Replace the injector if necessary.*