Adjusting Basic Idle FAQ
FAQ provided by Thomas Townsend (firstname.lastname@example.org) and
Ywan Mason (email@example.com)
Greetings from SAABTECH & SAABMASTER
The following is the adjustment procedure for basic idle on saab
900/9000's 16v with the gold colored aic valve that has three wires
connected to it.
Tools needed are:
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 7mm socket and short
extension. "To loosen the throttle switch"
3. A 8mm 1/4" drive socket "To loosen the lock nut on the adjustment for
the throttle screw"
4. A small streight 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.
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 usualy 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 needs to be adjusted"
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 its self." Use tool item #6.
5. Loosen the throttle switch " 7mm socket, tool item #2 " make sure it
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. repeate 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
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 untill 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 untill you get a change. Lock the throttle screw down "8mm nut"
7. ADJUST THROTTLE SWITCH:
Take your multi meter, turn it on and set to ohms or cont. touch the
end of the test leeds together and observe the value "0" "this is a
Disconnect the leed ends and observe the value "OL" "this is no circut"
A. Connect the test leeds to pins #1 & #2 at the throttle switch.
Rotate the switch untill you get a circut "0", Tighten down the 7mm
hold down screws. Open and close the throttle and observe:
1. Circut at idle "0"
2. No circut 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. YOUR DONE
NOTES: The sympthons of basic idle speed out of adjustment are : stall
at start up, stalls or tries to stall on deceleration and the problem
becomes more pronounced with the a/c turned on. The concept is the basic
idle has to be adjusted to a certain point in order for the computer to
control the idle speed. As the aic valve opens it allows the engine
speed to increase as in the case of when you turn on your a/c, the load
of the compressor slows your idle down - the computer see's this and
opens up the aic valve to increase idle speed.
THE CAUSE: The throttle bore becomes coated with carbon sludge from the
pcv system, therefor restricting the clerance "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.
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