Tune Up And Torque Specifications (1988-1993 2.8L Chevrolet S10 Pickup, GMC S15 Pickup, GMC Sonoma)

Tune Up And Torque Specifications (1988, 1989, 1990, 1991, 1992, 1993 2.8L V6 TBI Chevrolet S10 Pickup, GMC S15 Pickup, And GMC Sonoma)

Having the right tune-up specification information is essential to keeping your 2.8L V6 Chevrolet S10 pickup (GMC S15 pickup, GMC Sonoma) on the road and running at its best.

Whether you're a seasoned mechanic or just a DIYer looking to keep your vehicle running smoothly, this post has you covered.

APPLIES TO: This tutorial applies to the following vehicles:

  • 2.8L Chevrolet S10 Pickup: 1988, 1989, 1990, 1991, 1992, 1993.
  • 2.8L GMC S15 Pickup: 1988, 1989, 1990.
  • 2.8L GMC Sonoma: 1991, 1992, 1993.

Ignition System Specifications

Spark Plug Air Gap
0.045 inches
Spark Plug Torque
11 lb.ft
Original Equipment Spark Plug
Spark Plug Cable Resistance
0-15 inch long cable 3,000 - 10,000 Ohms
15-25 inch long cable 4,000 - 15,000 Ohms
25-35 inch long cable 6,000 - 20,000 Ohms
Base Ignition Timing
10° BTDC (before top dead center).
NOTE: The SET TIMING connector must be disconnected.

Ignition timing adjustment procedure:

  • Start the engine and let it reach its normal operating temperature.
  • Keep the air cleaner installed.
  • A/C must be OFF.
  • Transmission in Park Or Neutral.
  • Disconnect the SET TIMING connector (tan with black stripe wire) taped to the harness below the heater case in the passenger compartment (see image 2 of 2 in the image viewer above).
  • The 4-wire distributor connector must remain connected to distributor.
  • Connect a timing light to the cylinder 1 spark plug wire.
  • Adjust to specification by loosening distributor hold down bolt and rotating the distributor.

Ignition system test tutorials:

Fuel System Specifications

1991-1994: Fuel Pressure With Key On Engine Off
9-13 PSI
Fuel Pressure With Key On Engine Running
9-13 PSI

The fuel pump pressure test is the most accurate way of testing the in-tank fuel pump of your 2.8L V6 Chevrolet S10 pickup (GMC S15 pickup, GMC Sonoma).

To perform the test, a special adapter must be used to connect the fuel pressure test gauge to the fuel system. This adapter is installed between the fuel filter and the fuel line.

The fuel pressure test kit, which includes the gauge and adapter, is not expensive and can be easily purchased at your local auto parts store or online.

I've written a step-by-step tutorial on how to test fuel pressure to make the process even easier for you.

Serpentine Belt Diagram

  • 2.8L engine without air conditioning and power steering, see figure 1 of 3.
  • 2.8L engine with power steering but without air conditioning, see figure 2 of 3.
  • 2.8L engine with power steering and air conditioning, see figure 3 of 3.

Chevrolet Vehicles:

  • S10 Pickup 2.8L
    • 1988, 1989, 1990, 1991 1992, 1993

GMC Vehicles:

  • S15 Pickup 2.8L
    • 1988, 1989, 1990
  • Sonoma 2.8L
    • 1991, 1992, 1993