Full Size Buick FWD V6-181 3.0L (1984)
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Idle Speed: Adjustments
Idle Speed
Midpoint of range given is the preferred setting speed
Idle speed is adjustable only if a specification is given under "Minimum Speed".
All 1982-86 W/TBI: Gain access to throttle stop screw. With engine at operating temperature, disconnect idle air controller and install special tool to
seal idle air passage of throttle body. Turn throttle stop screw to specified minimum speed value.
All 1982-86 W/MFI; All 1987-90 W/TBI or MFI ex. 2.3, 2.8L, 3.3L, 1988-90 3.8L: 1.8L (112) Turbo, disconnect PCV valve hose and allow engine to
draw air for two minutes. Disconnect IAC electrical lead and adjust setting speed to specified value. Others, ground diagnostic lead and turn ignition on
for 30 seconds. Remove IAC electrical lead and remove ground from diagnostic connector. Start engine and adjust setting speed to specified value.
All carburetted W/ISC: With engine at operating temperature, turn ignition off and disconnect harness from ISC. Apply 12 volts (+) to third terminal
from top of ISC (C),and ground the fourth terminal from top (D) only long enough to retract ISC plunger. With engine running, set minimum idle to
specified value by adjusting carb base screw. Apply 12 volts (+) to fourth terminal from top of ISC (D) and ground the third terminal from top (C) only
long enough to fully extend ISC plunger. Set maximum speed to specified value by turning ISC plunger head.
Never apply voltage to first two upper terminals (A & B) or damage to the unit will result.
All carburetted W/ILC: Disconnect and plug vacuum hoses at EGR and canister purge valves. With engine at operating temperature, remove vacuum
hose from ILC and plug. Set maximum speed to specified value by holding hex nut and turning plunger shaft. Reconnect ILC vacuum hose and check
that minimum speed is at specified value. To adjust, remove rubber and metal plugs from rear center outlet tube, insert a 3/32" allen wrench. Remove
ILC hose and plug. Connect a remote vacuum source and apply vacuum to the unit. Adjust carb base screw to obtain specified shutdown value.