Engine Controls - Adjustments: Other Chevrolet Prizm I

ENGINE MECHANICAL

Before performing any on-vehicle adjustments to fuel or ignition systems, ensure engine mechanical condition is okay.

1.0L

Note. Hydraulic lash adjusters are used. No adjustment is required.

1.3L

1. Disconnect the negative battery cable.
2. Remove the valve rocker-arm cover.
3. Turn the crankshaft clockwise until the alignment notch on the crankshaft pulley (1) with the "0" mark on the engine front cover tab.
4. Check that the rocker arms of the number 1 cylinder are off the respective cam lobes of the camshaft. If they are not, rotate the crankshaft clockwise one revolution until the alignment notch on the crankshaft pulley is aligned with the "0" mark on the engine front cover tab.
5. Using a feeler gauge, measure the clearance between valves (1 intake), (2 intake), (1 exhaust) and (3 exhaust). See «VALVE LASH SPECIFICATIONS»(ref-165-S25382382132008102000000) table.
6. Turn the crankshaft clockwise 1 revolution until the alignment notch on the crankshaft pulley is aligned with the "0" mark on the engine front cover tab.
7. Using a feeler gauge, measure the clearance between valves (3 intake), (4 intake), (2 exhaust) and (4 exhaust). See «VALVE LASH SPECIFICATIONS»(ref-165-S25382382132008102000000) table.
8. Install the valve rocker-arm cover.
9. Connect the negative battery cable.

VALVE LASH SPECIFICATIONS

PRIZM

1. Disconnect negative battery cable. Remove valve cover and gaskets. Rotate crankshaft until cylinder No. 1 is at TDC of compression stroke. Ensure timing mark on crankshaft pulley aligns with "0" mark on engine front cover tab.
2. Valve lifters should be loose on cylinder No. 1, and tight on cylinder No. 4. If lifters on both valves are not as specified, rotate crankshaft one revolution (360 degrees) and realign crankshaft pulley mark.
3. Using a feeler gauge, measure and record clearance between camshaft lobe and adjuster shim on intake valves of cylinders No. 1 and 2, and exhaust valves of cylinders No. 1 and 3. Ensure valve clearance is within specification. See «VALVE CLEARANCE SPECIFICATIONS»(ref-165-S04166398672000030800000) table. If valve clearance if not within specification, go to step 5. If valve clearance is within specification, go to next step.
4. Rotate crankshaft one revolution (360 degrees). Using a feeler gauge, measure and record clearance at intake valves of cylinders No. 3 and 4, and exhaust valves of cylinders No. 2 and 4. Ensure valve clearance is within specification. See «VALVE CLEARANCE SPECIFICATIONS»(ref-165-S04166398672000030800000) table. If valve clearance if not within specification, go to next step.
5. To adjust valves, camshafts must be removed. See appropriate article in ENGINES. Once camshafts are removed, remove lifters from lifter bores of valves out of specification. Go to next step.
6. Using a micrometer, measure thickness of removed lifter. (Scheme 2) Compare measurement with valve clearance recorded earlier. Select proper lifter thickness for require valve clearance. Repeat for appropriate valves. Install lifters and camshafts. DO NOT install timing chain at this time. Go to next step.
7. Re-measure valve clearance. Ensure valve clearance is within specification. See «VALVE CLEARANCE SPECIFICATIONS»(ref-165-S04166398672000030800000) table. Reassemble timing chain. To install remaining components, reverse removal procedure.

VALVE CLEARANCE SPECIFICATIONS

Scheme 2

METRO & FIREFLY (CANADIAN)

Note. Metro & Firefly (Canadian) with 1.3L engine is equipped with an electronic computer-controlled ignition system. Ignition timing is not adjustable.

Metro & Firefly (Canadian) 1.0L

1. Start engine and allow it to reach normal operating temperature. Ensure all accessories and A/C (if equipped) are turned off, and transaxle is in Park (A/T) or Neutral (M/T) with parking brake fully applied. Ensure idle speed is within specification. Adjust idle speed first if necessary. See «IDLE SPEED»(ref-165-S16210101532000030800000) under IDLE SPEED & MIXTURE.
2. Connect timing light to No. 1 spark plug wire. Access 6-pin duty check DLC, located next to PCM behind glove box. (Scheme 3) Connect a fused jumper wire between duty check DLC cavities No. 4 and 5.
3. Check timing mark on crankshaft pulley with timing marks on timing belt cover. (Scheme 4) Notch on crankshaft pulley should line up with appropriate degree mark on timing indicator as specified by underhood emissions label.
4. If ignition timing is not as specified, loosen distributor hold-down flange bolts, and rotate distributor to obtain correct ignition timing. Tighten distributor hold-down flange bolts to 11 ft. lbs. (15 N.m). Recheck ignition timing. Ensure ignition timing advances as engine speed is increased. Turn engine off. Remove jumper wire from duty check DLC. Remove test equipment.

Scheme 3

Scheme 4

Note. Prizm is equipped with an electronic computer-controlled ignition system. Ignition timing is not adjustable.

IDLE SPEED & MIXTURE

Note. Air/fuel mixture is controlled by Powertrain Control Module (PCM) and is not adjustable.

Note. Idle speed inspection procedure without scan tool for Metro & Firefly (Canadian) 1.0L is not available from manufacturer.

Idle speed adjustment is controlled by Powertrain Control Module (PCM). PCM controls idle speed with Idle Air Control (IAC) valve. No adjustment is required. Check IAC valve as necessary.

IDLE SPEED SPECIFICATIONS (1)

Prizm (If Equipped)

1. Start engine and allow it to reach normal operating temperature. Install scan tool and monitor engine speed. Disconnect throttle opener vacuum hose from throttle opener, and plug hose.
2. Maintain engine speed at approximately 2500 RPM. Release throttle lever. Ensure throttle opener is set with engine speed at 1300-1500 RPM and radiator fan motor is off. If throttle opener does not set, replace throttle opener.
3. If throttle opener setting speed requires adjustment, turn adjusting screw clockwise to increase engine speed or counterclockwise to decrease engine speed. (Scheme 5) Reconnect throttle opener vacuum hose to throttle opener and disconnect scan tool.

Scheme 5

THROTTLE POSITION (TP) SENSOR

Note. TP sensor is not adjustable on Prizm, or on Metro & Firefly (Canadian) equipped with 1.3L engine. Replace TP sensor as necessary. Perform all testing procedures with engine at normal operating temperature.