THE CAUSE: The throttle bore becomes coated with carbon sludge from the PCV system, therefore restricting the clearance "opening" between the throttle plate and bore. Less space = less air flow for idle= less idle speed. In many cases all you need to do is spray carb cleaner into the throat of the air horn on the intake manifold, brush with a tooth brush and spray off again, reassemble and your idle should be up to par.
Tools needed:
1. A wire about 2 foot long with male connector on one end and a clip on the other end. "The test wire"
2. A 1/4" drive driver handle or ratchet with 7 mm socket and short extension. "To loosen the throttle switch"
3. A 8 mm 1/4" drive socket "To loosen the lock nut on the adjustment for the throttle screw"
4. A small straight blade screwdriver "For turning the throttle screw"
5. A ohm meter "For checking the adjustment of the throttle switch"
6. A small jump wire "For bridging the throttle switch connector on the wiring harness at the throttle switch"
1. Allow Saab to reach operating temp. "fans cycling".
A. Make sure A/C is turned OFF
2. Locate the test connector wire. 900 Pictures
A. On 900's it is located behind the a/c evaporator box, near the gang connectors and is green with a red stripe "single wire with plastic connector on the end"
B. On 9000's its on the bulkhead on drivers side near the hood hinge "rectangular dark colored connector usual with cover on top" The proper connection point is the pin that is closest to the driver and engine" standing with your toes pointed at the center of the left tire side, extend your right hand outward at 45 deg. and there it is. Its the connector furthest to the right and closest to the center of the car.
3. Ground the test wire "with the Saab idling"
IF- STALLS or idles very very slowly about to stall... = "Basic idle speed needs to be adjusted up"
IF- NO CHANGE "the system may have the basic idle speed set a little high OR the throttle switch may be out of adjustment.
4. Remove connector at the throttle switch and bridge the center wire and the wire closest to the driver "#1 & #2 the numbers are under the boot on the connector." Use tool item #6.
5. Loosen the throttle switch " 7 mm socket, tool item #2 " make sure it will rotate.
6. SET BASIC IDLE: Loosen the throttle adjustment screw lock nut and turn the screw clock wise to increase speed " use tool item #3 & #4 "
SET THE IDLE SPEED TO 750 - 800 RPM with the test wire grounded.
Disconnect test wire and the engine speed should rev up and settle down to a good idle. repeat the connection and disconnection of the test wire and observe the function as stated above.
IF disconnecting the test wire and there is no change = check and make sure instruction #4 is in order. OR smack the AIC valve with a screw driver handle and see if it tries to smarten up after repeating the test.
IF so = the AIC valve may be sticking.
I HAVE TORN DOWN MALFUNCTIONING VALVE AND FOUND THAT ALL THREE BRUSH CONTACT POINTS AT THE COMMUTATOR HAVE BURNT HOLES INTO THE COMMUTATOR. THE POINTS STICK IN THE HOLES AND CAUSE THE VALVE NOT TO WORK. Most people wait until the AIC valve sticks in the high idle position, before buying new valve.
IF you set the basic speed too high you will not notice any change in RPM when you ground the test wire. Back off on the throttle adjustment slightly until you get a change. Lock the throttle screw down "8 mm nut"
7. ADJUST THROTTLE SWITCH:
Take your multi meter, turn it on and set to ohms or cont. touch the end of the test leads together and observe the value "0" "this is a circuit"
Disconnect the lead ends and observe the value "OL" "this is no circuit"
A. Connect the test leads to pins #1 & #2 at the throttle switch.
B. Rotate the switch until you get a circuit "0", Tighten down the 7 mm hold down screws. Open and close the throttle and observe:
1. Circuit at idle ="0"
2. No circuit at open throttle ="OL"
IF THIS IS THE CASE = YOU HAVE JUST ADJUSTED THE THROTTLE SWITCH!
Disconnect bridge wire and test wire and reconnect the throttle switch wire harness connector to the switch.
YOU'RE DONE