GM – CAMARO 1982-1992 – Repair Guide (Checked by WxMax) 662
Fig. 3: Idle speed adjustm ents - 4-bbl carburetor
WITH AIR CONDITIONING
The engine must be running in "Closed Loop" mode (engine fully warmed) when
making all idle speed adjustments. In this mode, the oxygen sensor affects
control of the fuel delivery.
1. Refer to the emission label on the vehicle and prepare the engine for
adjustments (set the timing). Se t the parking brake. Connect a
tachometer to the dist ributor connector.
2. Place the transmission in DRIVE for automatic transmission, or
NEUTRAL for manual transmission. Tu rn the air conditioning OFF.
3. De-energize the idle speed solenoid by disconnecting the electrical lead.
4. Set the basic idle speed rpm by turning the idle speed screw. After
adjustment, reconnect the solenoid electrical lead.
5. Disconnect the electrical lead from the A/C compressor and turn the A/C
switch ON.
6. Open the throttle partially to ensure that the solenoid plunger is fully
extended, and allow the throttle lever to close on the plunger.
7. Turn the solenoid plunger to adj ust to the specified rpm. After
adjustment, reconnect the A/C co mpressor lead and turn the air
conditioning OFF.
8. Remove the tachometer and install the air cleaner.
GM – CAMARO 1982-1992 – Repair Guide (Checked by WxMax) 732
MINIMUM IDLE AND THROTTL
E VALVE SYNCHRONIZING
The throttle position of each throttle body must be balanced so that the throttle
plates are synchronized and open si multaneously. These adjustment
procedures must be followed AFTER performing the "Preliminary Adjustments".
1. Remove the air cleaner and plug the vacuum port on the rear TBI unit for
the thermostatic air cleaner.
2. Remove the tamper resistant pl ugs covering both unit throttle stop
screws, if necessary.
3. Block the drive wheels and apply the parking brake.
4. Connect a tachometer to measure rpm.
5. Start the engine and allo w the engine rpm to stabilize at normal operating
temperature.
6. Have a helper apply the brakes and place the transmission in DRIVE.
7. Plug the idle air pass ages of each throttle body with plugs (J-33047 or
equivalent). Make sure the plugs are seated fully in the passage so that
no air leaks exist. The engine rpm should decrease below curb idle
speed. If the engine rpm does not decreas e, check for a vacuum leak.
8. Remove the cap from the ported tube on the rear TBI unit and connect a
vacuum gauge or water manometer.
9. Adjust the rear unit throttle stop screw to obtain approximately
1/2 in. Hg
as read on the vacuum gauge, or 6 in. H
2O as read on the manometer. If
not able to adjust to this level, check that the front unit throttle stop is not
limiting throttle travel.
10. Remove the vacuum gauge or manometer from t he rear unit and install
the cap on the port ed vacuum tube.
11. Remove the cap from the ported va cuum tube on the front TBI unit and
install the gauge or manomet er as before. If the reading is not the same
as the rear unit, proceed as follows: a. Locate the throttle synchronizing screw and collar on the front TBI
unit. The screw may be welded to discourage tampering with this
adjustment. Break the weld, if ne cessary, and install a new screw
with a thread seali ng compound applied.
b. Adjust the screw to obtain approximately
1/2 in. Hg as read on the
vacuum gauge, or 6 in. H
2O on the manometer.
12. Remove the gauge or manometer fr om the ported tube and reinstall the
cap.
13. Adjust the rear throttle stop screw to obtain 475 rpm, with the
transmission in D and the parking brake applied. On manual
transmission models, leave the gear selector in N.
14. Turn the ignition OFF and pl ace automatic transmission in N.
15. Remove idle air passage plugs.
16. Start the engine. It may run at a high rpm but the engine speed should
decrease when the idle air control va lves close the air passages. Stop
the engine when the rpm decreases.
17. The throttle position sensor (TPS) voltage should be checked and adjusted, if necessary.
18. Connect the vacuum line to the TBI unit and install the air cleaner.
19. Reset the idle speed control motors by driving the vehicle to 45 mph.
