ENGINE COMPRESSION
| Application | Compression Ratio |
|---|---|
| 2.5L (VIN E) | 8.3:1 |
| 2.8L (VIN R) | 8.9:1 |
| 3.1L (VIN D) | 8.9:1 |
| 4.3L (VIN Z) | 9.3:1 |
| 5.0L (VIN H) | 9.3:1 |
| 5.7L (VIN K) | 8.2:1 |
| 6.2L Diesel (VIN C) | 21.3:1 |
| 7.4L (VIN N) | 7.9:1 |
COMPRESSION SPECIFICATIONS
VALVE CLEARANCE
Note. All models are equipped with hydraulic lifters. No adjustments are required.
2.5L (VIN E)
I-E-I-E-E-I-E-I (Front-to-rear).
2.8L (VIN R)
Left Bank - E-I-I-E-I-E (Front-to-rear).
Right Bank - E-I-E-I-I-E (Front-to-rear).
3.1L (VIN D)
Left Bank - E-I-I-E-I-E (Front-to-rear).
Right Bank - E-I-E-I-I-E (Front-to-rear).
4.3L (VIN Z)
Left Bank - E-I-E-I-I-E (Front-to-rear).
Right Bank - E-I-I-E-I-E (Front-to-rear).
5.0L (VIN H)
Both Banks - E-I-I-E-E-I-I-E (Front-to-rear).
5.7L (VIN K)
Both Banks - E-I-I-E-E-I-I-E (Front-to-rear).
6.2L (VIN C)
Left Bank - I-E-I-E-I-E-I-E (Front-to-rear).
Right Bank - E-I-E-I-E-I-E-I (Front-to-rear).
7.4L (VIN N)
Left Bank - E-I-E-I-E-I-E-I (Front-to-rear).
Right Bank - I-E-I-E-I-E-I-E (Front-to-rear).
IGNITION COIL
| Application | Ohms |
|---|---|
| All Models w/HEI-EST | 500-1500 |
PICK-UP COIL RESISTANCE
HIGH TENSION WIRE RESISTANCE
| Application | Ohms |
|---|---|
| All Models | 30,000 Maximum |
HIGH TENSION WIRE RESISTANCE
SPARK PLUGS
| Application | AC |
|---|---|
| 2.5L (VIN E) | R43TS6 |
| 2.8L (VIN R) | R43TSK |
| 3.1L (VIN D) | R43TS |
| 4.3L (VIN Z) | CR43TS |
| 5.0L (VIN H) | CR43TS |
| 5.7L (VIN K) | CR43TS |
| 7.4L (VIN N) | CR43RS |
SPARK PLUG TYPE
| Application | Gap - In. (mm) | Torque - Ft. Lbs. (N.m) |
|---|---|---|
| 2.5L (VIN E) | .060 (1.52) | 17 (23) |
| 2.8L (VIN R) | .060 (1.52) | 22 (30) |
| 3.1L (VIN D) | .045 (1.14) | 18 (24) |
| 4.3L (VIN Z) | .035 (0.89) | 22 (30) |
| 5.0L (VIN H) | .035 (0.89) | 11 (15) |
| 5.7L (VIN K) | .035 (0.89) | 11 (15) |
| 7.4L (VIN N) | .035 (0.89) | 11 (15) |
SPARK PLUG SPECIFICATIONS
2.5L (VIN E) Firing Order & Timing Marks. Scheme 1
2.8L (VIN R) Firing Order & Timing Marks. Scheme 2
3.1L (VIN D) Firing Order & Timing Marks. Scheme 3
4.3L (VIN Z) Firing Order & Timing Marks. Scheme 4
5.0L, 5.7L & 7.4L Firing Order & Timing Marks. Scheme 5
6.2L Diesel Engine Firing Order. Scheme 6
IGNITION TIMING
Note. For timing procedures, see ADJUSTMENTS article.
| Application | (1) Manual Transmission | (2) Automatic Transmission |
|---|---|---|
| 2.5L (VIN E) | 8 @ Idle | 8 @ Idle |
| 2.8L (VIN R) | 10 @ Idle | 10 @ Idle |
| 3.1L (VIN D) | 10 @ Idle | 10 @ Idle |
| 4.3L (VIN Z) | 0 @ Idle | 0 @ Idle |
| 5.0L (VIN H) | 0 @ Idle | 0 @ Idle |
| 5.7L (VIN K) | 0 @ Idle | 0 @ Idle |
| 7.4L (VIN N) | 4 @ Idle | 4 @ Idle |
| (1) Set in Neutral. (2) Set in Neutral or Park. | ||
| (1) | Set in Neutral. |
| (2) | Set in Neutral or Park. |
IGNITION TIMING (Degrees BTDC @ RPM)
FUEL PUMP
| Application | Psi (kg/cm 2 ) |
|---|---|
| 6.2L Diesel (VIN C) | 8-12 (.5-.8) |
| All Others | 9-13 (.63-.91) |
FUEL PUMP PERFORMANCE
INJECTOR RESISTANCE
| Application | Resistance (Ohms) |
|---|---|
| All Except 3.1L (VIN U) | 1.3 |
| 3.1L (VIN U) | 1.2 |
INJECTOR RESISTANCE SPECIFICATIONS (At 140°F (60°C))
IDLE SPEED & MIXTURE
Note. Idle mixture on fuel injected models is controlled by the ECM and is not adjustable.
THROTTLE POSITION SENSOR (TPS)
Note. TPS is adjustable only on 2.8L (VIN R) and 6.2L Diesel (VIN C) engines. For further testing, refer to appropriate TESTS W/CODES article.
| Application | (1) (2) Voltage |
|---|---|
| 2.8L (VIN R) | .42-.45 |
| 6.2L Diesel (VIN U) | 1.2 |
| (1) At idle RPM or closed throttle. (2) This is a TPS Voltage Ratio. For adjustment procedure see ADJUSTMENTS article in the ENGINE PERFORMANCE Section. | |
| (1) | At idle RPM or closed throttle. |
| (2) | This is a TPS Voltage Ratio. For adjustment procedure see ADJUSTMENTS article in the ENGINE PERFORMANCE Section. |
TPS ADJUSTMENT VOLTAGE