BELT TENSION
| Application | (1) Belt Deflection |
|---|
| 2.0L |
| Accessory Drive Belt | (2) |
| Water Pump |
| New Belt | 0.16-0.20" (4.1-5.1 mm) |
| Used Belt (3) | 0.20-0.27" (5.1-6.9 mm) |
| 2.5L |
| A/C Compressor | 0.16-0.28" (4.1-7.1 mm) |
| Generator/Water Pump |
| New Belt | 0.28-0.35" (7.1-8.9 mm) |
| Used Belt (3) | 0.35-0.43" (8.9-11.0 mm) |
| Power Steering | 0.16-0.28" (4.1-7.1 mm) |
| All Others (Serpentine Belt) | (2) |
| (1) Deflection is with 22 lbs. (10 kg) pressure applied midway on longest belt run. (2) Adjustment of serpentine belt is not necessary. Belt tension is maintained by spring-tensioned idler pulley (some equipped with belt wear indicator). (3) Used belt is a belt in operation for more than 5 minutes. |
| (1) | Deflection is with 22 lbs. (10 kg) pressure applied midway on longest belt run. |
| (2) | Adjustment of serpentine belt is not necessary. Belt tension is maintained by spring-tensioned idler pulley (some equipped with belt wear indicator). |
| (3) | Used belt is a belt in operation for more than 5 minutes. |
ENGINE COMPRESSION
| Application | Specification - psi (kPa) |
|---|
| Normal Compression Pressure |
| 2.0L | 199 (1372.1) |
| 2.2L |
| Sonoma & S10 Pickup | (1) |
| VUE | 185-225 (1275.6-1551.4) |
| 2.5L | 199-227 (1372.1-1565.2) |
| 3.0L | 180-190 (1241.1-1310.1) |
| 4.2L | 215 (1482.4) |
| 4.3L | (2) |
| 4.8L, 5.3L & 6.0L |
| Except Sierra & Silverado | (1) |
| Sierra & Silverado | (2) |
| 5.0L & 5.7L | (2) |
| 6.5L | (2) |
| 6.6L | (2) |
| All Others | (1) |
| Minimum Compression Pressure |
| 2.0L | 170 (1172.2) |
| 2.2L |
| Sonoma & S10 Pickup | (1) |
| VUE | 185 (1275.6) |
| 2.5L | 185 (1275.6) |
| 3.0L | 100 (689.5) |
| 4.2L | (3) |
| 4.3L | (2) |
| 4.8L, 5.3L & 6.0L |
| Except Sierra & Silverado | (1) |
| Sierra & Silverado | (2) |
| 5.0L & 5.7L | (2) |
| 6.5L | (4) 370 (2551.2) |
| 6.6L | 300 (2068.5) |
| All Others | (1) |
| Compression Variance |
| 2.0L & 2.5L | 15 (103.4) |
| 6.6L | 50 (344.8) |
| All Others | (2) |
| (1) Lowest compression reading should not be less than 70 percent of highest compression reading. No cylinder compression reading should be less than 100 psi (689.5 kPa). (2) Information is not available from manufacturer. (3) Lowest compression reading should not be less than 70 percent of highest compression reading. (4) Subtract 8 psi (55.2 kPa) for every 1000 ft. (304.8 M) of elevation above seal level. Measurement is taken with cold engine speed of at least 100 RPM, or hot engine speed of at least 180 RPM. |
| (1) | Lowest compression reading should not be less than 70 percent of highest compression reading. No cylinder compression reading should be less than 100 psi (689.5 kPa). |
| (2) | Information is not available from manufacturer. |
| (3) | Lowest compression reading should not be less than 70 percent of highest compression reading. |
| (4) | Subtract 8 psi (55.2 kPa) for every 1000 ft. (304.8 M) of elevation above seal level. Measurement is taken with cold engine speed of at least 100 RPM, or hot engine speed of at least 180 RPM. |
ENGINE COMPRESSION SPECIFICATIONS
VALVE CLEARANCE
| Application | In. (mm) |
|---|
| 6.6L |
| Intake & Exhaust | 0.012 (0.30) |
| All Others | (1) |
| (1) Equipped with hydraulic lifters. Adjustment is not required. |
| (1) | Equipped with hydraulic lifters. Adjustment is not required. |
VALVE CLEARANCE SPECIFICATIONS
HIGH TENSION WIRE RESISTANCE
| Application | Ohms |
|---|
| 2.0L, 2.5L, 3.0L & 4.2L | (1) |
| 2.2L |
| Sonoma & S10 Pickup | 12,000 Per Ft. |
| VUE | (1) |
| 3.4L | 3000 Per Ft. |
| 4.3L, 4.8L, 5.3L, 6.0L & 8.1L | 1000 Per Ft. |
| 5.0L & 5.7L | 700 Per Ft. |
| (1) Not equipped with high tension wires. Ignition coils are connected directly to spark plugs by boots. |
| (1) | Not equipped with high tension wires. Ignition coils are connected directly to spark plugs by boots. |
HIGH TENSION WIRE RESISTANCE
SPARK PLUGS
| Application | Type | Part No. |
|---|
| 2.0L & 2.5L | Denso | K20PR-U11 Or SK16PR11 |
| NGK | BKR6E11 Or 1FR5J11 |
| 2.2L |
| Sonoma & S10 Pickup | AC | 41-948 |
| VUE | GM | 12569190 |
| 3.0L | Bosch | FLR-LTE |
| 3.4L | AC | 41-940 |
| 4.2L | AC | 41-965 |
| 4.3L | AC | R41-932 |
| 4.8L, 5.3L & 6.0L | AC | 25171803 |
| NGK | 12567759 |
| 5.0L | AC | 41-952 |
| 5.7L |
| CNG Engine | AC | 41-932 |
| Gasoline Engine | AC | 41-952 |
| 8.1L | Denso | TJ14R-P15 |
| Application | Gap - In. (mm) | Torque - Ft. Lbs. (N.m) |
|---|
| 2.0L & 2.5L | .039-.043 (1.0-1.1) | 18 (25) |
| 2.2L |
| Sonoma & S10 Pickup | .040 (1.02) | 13 (18) |
| VUE | .045 (1.14) | 15 (20) |
| 3.0L | .035-.043 (0.9-1.1) | 15 (20) |
| 4.2L | .050 (1.27) | 13 (18) |
| 4.3L | .060 (1.52) | 11 (15) |
| 8.1L | .060 (1.52) | 15 (20) |
| All Others | Iridium .040 in. (1.04 mm) Platinum .060 in. (1.52 mm) | 11 (15) |
SPARK PLUG SPECIFICATIONS
FIRING ORDER
Scheme 1
Scheme 1: Firing Order (2.0L & 2.2L)
Scheme 2
Scheme 2: Firing Order (2.5L)
Scheme 3
Scheme 3: Firing Order (3.0L "L" & "Z" Series & 3.4L "A" & "B" Series)
Scheme 4
Scheme 4: Firing Order (3.4L "U" Series)
Scheme 5
Scheme 5: Firing Order (4.2L)
Scheme 6
Scheme 6: Firing Order (4.3L)
Scheme 7
Scheme 7: Firing Order (4.8L, 5.3L, 6.0L, 6.5L Diesel & 8.1L)
Scheme 8
Scheme 8: Firing Order (5.0L & 5.7L)
Scheme 9
Scheme 9: Firing Order (6.6L Diesel)
EXCEPT TRACKER
All models are equipped with an electronic computer-controlled ignition system. Ignition timing is not adjustable.
TRACKER
Timing should be set to 5 degrees BTDC. For adjustment procedure, see appropriate ON-VEHICLE ADJUSTMENTS article.
INJECTION PUMP TIMING (DIESEL)
Injection pump timing can be checked using scan tool. For adjustment procedure, see appropriate ON-VEHICLE ADJUSTMENTS article.
FUEL PUMP
| Application | Psi (kPa) |
|---|
| 2.0L & 2.5L | (1) 36-43 (248.2-296.5) |
| 2.2L |
| Sonoma & S10 Pickup | 41-47 (282.7-324.1) |
| VUE | 50-60 (344.8-413.7) |
| 3.0L | 50-60 (344.8-413.7) |
| 3.4L | 52-59 (358.5-406.8) |
| 4.2L | 48-52 (331.0-358.5) |
| 4.3L |
| Astro, Safari, Sierra & Silverado | 55-62 (379.2-427.5) |
| Blazer, Express, Jimmy Canadian, Savana, Sonoma & S10 | 60-66 (413.7-455.1) |
| 4.8L, 5.3L & 6.0L |
| Ethanol (VIN "Z") | 48-54 (331.0-372.3) |
| Gasoline (VIN "V", "T" Or "U") | 55-62 (379.2-427.5) |
| 5.0L | 59-66 (406.8-455.1) |
| 5.7L |
| CNG Engine | 130-220 (896.4-1516.9) |
| Gasoline Engine | 59-66 (406.8-455.1) |
| 6.5L |
| Non-Turbo Engine | (2) 1500 (10,342.5) |
| Turbo Engine | (2) 1700 (11,721.5) |
| 6.6L | (3) 23,206 (160,005.4) |
| 8.1L | 55-62 (379.2-427.5) |
| (1) Pressure should maintain at least 25 psi (172.4 kPa) for one minute after fuel pump is turned off. (2) Measured on diesel fuel injection nozzle side. (3) Measured on fuel injection pump high pressure side. |
| (1) | Pressure should maintain at least 25 psi (172.4 kPa) for one minute after fuel pump is turned off. |
| (2) | Measured on diesel fuel injection nozzle side. |
| (3) | Measured on fuel injection pump high pressure side. |
INJECTOR RESISTANCE
| Application | Ohms |
|---|
| 2.0L | 13-16 |
| 2.2L |
| Sonoma & S10 Pickup | 11-14 |
| VUE | 12-13 |
| 2.5L | 9-14 |
| 3.0L | 15.1-15.9 |
| All Others | 11-14 |
| (1) Injector resistance specification is at 50-95°F (10-35°C). |
| (1) | Injector resistance specification is at 50-95°F (10-35°C). |
INJECTOR RESISTANCE SPECIFICATIONS (1)
IDLE SPEED & MIXTURE
Note. Idle mixture is controlled by Powertrain Control Module (PCM). Idle speed is preset by manufacturer and is not adjustable.
THROTTLE POSITION SENSOR
Note. Throttle Position (TP) sensor is not adjustable unless specified otherwise. For further testing procedures, refer to appropriate SELF-DIAGNOSTICS or SYSTEM & COMPONENT TESTING article.
Note. On some engines, throttle control is electronic with NO mechanical link from engine to accelerator pedal. The PCM monitors the position of accelerator pedal based on signals from a non-adjustable Accelerator Pedal Position (APP) module. The APP module may be mounted above or below the accelerator pedal.
| Application | (1) Voltage |
|---|
| 2.0L | 0.5-1.2 To 3.4-4.7 |
| 2.2L |
| Sonoma & S10 Pickup | 1.0- 4.0 |
| VUE | (2) |
| 2.5L | 0.4-1.2 To 3.4-4.7 |
| 3.0L | (3) |
| 3.4L, 4.3L, 4.8L, 5.3L & 6.0L | 1.0-4.0 |
| 4.2L | (4) |
| 5.0L | 1.2-4.5 |
| 5.7L |
| CNG Engine | 0.5-4.0 |
| Gasoline Engine | 1.2-4.5 |
| 6.5L | (5) |
| 6.6L | (6) |
| 8.1L |
| Sensor 1 | (7) |
| Sensor 2 | (7) |
| (1) Voltage range is from idle to wide open throttle. (2) TP sensor is 2 individual units within one housing. TP sensor 1 signal voltage ranges from 4.25 volts with throttle closed to 0.59 volt at wide open throttle. TP sensor 2 signal voltage ranges from 0.75 volt with throttle closed to 4.41 volts at wide open throttle. (3) TP sensor is 2 individual units within one housing. TP sensor 1 signal voltage ranges from 0.50 volt with throttle closed to 4.15-4.35 volts at wide open throttle. TP sensor 2 signal voltage ranges from 4.45 volts with throttle closed to 0.60-0.80 volt at wide open throttle. (4) TP sensor is 2 individual units within one housing. TP sensor 1 signal voltage is about 5 volts with throttle closed and decreases as throttle is opened. TP sensor 2 signal voltage increases as throttle is moved from a closed position to wide open throttle position. (5) 6.5L diesel engine PCM uses 3 Accelerator Pedal Position (APP) sensors in a module rather than a Throttle Position (TP) sensor to control fuel delivery. PCM requires information from APP 1 sensor only, other sensors act as fail-safes. APP 1 sensor voltage ranges from about 0.35-0.95 volt with throttle closed to more than 4 volts at wide open throttle. APP 2 sensor voltage ranges from about 4.5 volts with throttle closed to about one volt at wide open throttle. APP 3 sensor voltage ranges from about 4 volts with throttle closed to about 2.5 volts at wide open throttle. (6) 6.6L diesel engine PCM uses 3 Accelerator Pedal Position (APP) sensors in a module rather than a Throttle Position (TP) sensor to control fuel delivery. PCM requires information from APP 1 sensor only, other sensors act as fail-safes. APP 1 sensor voltage ranges from 0.52-0.80 volt with throttle closed to 2.12-2.65 volts at wide open throttle. APP 2 sensor voltage ranges from 4.25-4.53 volts with throttle closed to 2.40-2.93 volts at wide open throttle. APP 3 sensor voltage ranges from 3.95-4.13 volts with throttle closed to 2.76-3.16 volts at wide open throttle. (7) TP sensor is 2 individual units within one housing. TP sensor 1 signal voltage ranges from about one volt with throttle closed to more than 3.5 volts at wide open throttle. TP sensor 2 signal voltage ranges from about 4 volts with throttle closed to less than 1.5 volts at wide open throttle. |
| (1) | Voltage range is from idle to wide open throttle. |
| (2) | TP sensor is 2 individual units within one housing. TP sensor 1 signal voltage ranges from 4.25 volts with throttle closed to 0.59 volt at wide open throttle. TP sensor 2 signal voltage ranges from 0.75 volt with throttle closed to 4.41 volts at wide open throttle. |
| (3) | TP sensor is 2 individual units within one housing. TP sensor 1 signal voltage ranges from 0.50 volt with throttle closed to 4.15-4.35 volts at wide open throttle. TP sensor 2 signal voltage ranges from 4.45 volts with throttle closed to 0.60-0.80 volt at wide open throttle. |
| (4) | TP sensor is 2 individual units within one housing. TP sensor 1 signal voltage is about 5 volts with throttle closed and decreases as throttle is opened. TP sensor 2 signal voltage increases as throttle is moved from a closed position to wide open throttle position. |
| (5) | 6.5L diesel engine PCM uses 3 Accelerator Pedal Position (APP) sensors in a module rather than a Throttle Position (TP) sensor to control fuel delivery. PCM requires information from APP 1 sensor only, other sensors act as fail-safes. APP 1 sensor voltage ranges from about 0.35-0.95 volt with throttle closed to more than 4 volts at wide open throttle. APP 2 sensor voltage ranges from about 4.5 volts with throttle closed to about one volt at wide open throttle. APP 3 sensor voltage ranges from about 4 volts with throttle closed to about 2.5 volts at wide open throttle. |
| (6) | 6.6L diesel engine PCM uses 3 Accelerator Pedal Position (APP) sensors in a module rather than a Throttle Position (TP) sensor to control fuel delivery. PCM requires information from APP 1 sensor only, other sensors act as fail-safes. APP 1 sensor voltage ranges from 0.52-0.80 volt with throttle closed to 2.12-2.65 volts at wide open throttle. APP 2 sensor voltage ranges from 4.25-4.53 volts with throttle closed to 2.40-2.93 volts at wide open throttle. APP 3 sensor voltage ranges from 3.95-4.13 volts with throttle closed to 2.76-3.16 volts at wide open throttle. |
| (7) | TP sensor is 2 individual units within one housing. TP sensor 1 signal voltage ranges from about one volt with throttle closed to more than 3.5 volts at wide open throttle. TP sensor 2 signal voltage ranges from about 4 volts with throttle closed to less than 1.5 volts at wide open throttle. |
THROTTLE POSITION (TP) SENSOR VOLTAGE
