So Fix it

An engines firing order is the sequence that each cylinder is used in power delivery. The firing order for the 6.6L turbo diesel V8 in the 2004 Chevrolet Silverado 2500 2WD is 1-2-7-8-4-5-6-3.

Gasoline Versus Diesel

In a gasoline engine, the distributor or Engine Control Unit sends electricity to individual spark plugs to ignite fuel in each cylinder in a specific order. In a diesel engine it is determined by the order in which fuel is injected into each cylinder.

Cylinder 1

Engine firing orders always start with cylinder number one, which on this engine is located at the front left of the engine from the drivers point of view.

Cylinder Banks

GM V8 cylinders are numbered 1-3-5-7 on the left (drivers) side of the engine, and 2-4-6-8 on the right (passenger) side.

Changing the resistor on the heater blower motor in your Silverado may be necessary if the blower will only run on one speed. When the resistor fails it allows full power to flow from the switch. This results in the fan running either on high speed or not at all, but none of the speeds in-between. Newer Chevy models do not use a traditional resistor; instead they use a controller, but the function is the same.

Instructions

1

Open the passengers side door of your truck and locate the sound insulator on the firewall just above the passenger floorboard. Pull the insulator back to expose the blower motor and HVAC duct under the dash.

2

Locate the controller on the face of the blower motor housing; identifying it by the wiring harness connection running from it to the blower motor. Disconnect the wiring harness connector from the controller and lay it aside.

3

Locate the two retaining bolts on the face of the controller and remove them with a socket and ratchet. Pull the controller off the blower and discard it.

4

Position the new controller on the face of the blower motor, insert the retaining bolts and tighten them with a socket and ratchet. Do not over tighten them or damage may occur to the HVAC housing.

5

Connect the wiring harness connector to the controller, snapping it into place. Push the sound insulator back in place and test the repair by running the fan through all the speeds, verifying it runs in all of them.

Replacing the serpentine belt on your 1990 Silverado pickup will help prevent an accidental belt failure when you least expect it. The belt turns every accessory on the front of the engine, including the water pump and alternator. If the belt breaks, the truck will overheat and lose electrical power for the ignition system. Check the belt for damage every time you change the oil in your truck. Replace the belt at the first sign of a problem.

Instructions

1

Raise the hood of your truck and prop it open. Locate the negative cable on the battery. Remove the retaining bolt with a wrench. Lift the cable off the terminal and set it aside.

2

Locate the serpentine belt tensioner on the front of the engine. Place a socket and breaker bar on the tensioner center bolt. Rotate it counterclockwise to loosen the belt. Remove the belt. Rotate the tensioner back to the home position. Discard the old belt.

3

Install a new belt over the pulleys on the front of the engine. Leave it off the tensioner for now. Routing the belt correctly is important, so check the diagram on the radiator support under the hood to verify the belt path.

4

Rotate the tensioner counterclockwise with the breaker bar and socket. Install the belt over the tensioner pulley and rotate the tensioner clockwise to tighten the belt. Remove the socket and breaker bar from the engine compartment.

5

Reattach the negative cable to the negative battery terminal. Reattach the retaining bolt and tighten it with a wrench. Close the hood of the truck.

Removal of the ignition coil from the engine in your 1996 Chevy Silverado may be necessary to access parts of the engine behind or below the coil or if the coil is failing and replacement becomes necessary. The ignition coil supplies high-voltage electricity to the spark plugs, by way of the distributor, to produce the spark required to fire the fuel in the engine cylinders. If the coil begins to fail, lower voltage to the spark plugs will result in weak spark and the engine will run poorly if at all.

Instructions

1

Locate the negative battery cable end on the battery terminal and loosen the clamp bolts with a wrench. Remove the cable from the terminal and set it aside, isolating it from the battery terminals.

2

Locate the ignition coil on the top of the engine, near the front on the drivers side. Pull the high-tension cable off the top of the coil and lay it off to one side. Locate the wiring harness connection on the side of the coil.

3

Depress the locking tab on the side of the wiring harness connector and remove the connector from the coil. Locate the two mounting bolts on the mounting bracket and remove them with a socket and ratchet.

4

Lift the coil and bracket off the engine. If you are installing a new coil, you will need to reuse the mounting bracket so do not discard it once you remove it from the engine.

You can clear the codes on your Chevy Silverado using an OBD scan tool, a hand-held computerized device available at most auto parts retailer. The tool is used to read the codes, and clear them after servicing or repairs. OBD stands for "On-Board Diagnostics." This is the computer that monitors all functions of the vehicle. When there is a malfunction within the Silverado, sensors positioned throughout the vehicle will send a trouble code to the OBD computer.

Instructions

1

Locate the data link connector (DLC) port that is the same size and shape as the OBD scan tools connective end. This port is located on the underside of the drivers side dash next to the steering column.

2

Plug the handheld scan tool into this port. Put the key into the ignition and turn it to the "II" position, but dont start the engine. This will turn on most scan tools. If not, locate the on/off switch and turn it on.

3

Wait for the scan tool to retrieve the codes, then press "Erase Codes."

4

Unplug the scan tool after it has finished erasing the codes. Start the engine and check to make sure all lights have turned off on the instrument cluster.

Replacing the serpentine belt tensioner on the engine of your 2002 Chevy Silverado may be necessary if the spring is worn or the tensioner is sticking. The tensioners job is to keep the slack out of your serpentine belt as it stretches and wears. If it is not working correctly, the belt may become loose and come off the pulleys, or damage may occur to the belt, pulleys and accessories. Replacement belt tensioners are available from the dealer or most parts stores.

Instructions

1

Raise the hood of your Silverado and locate the negative battery cable on the battery. Remove the retaining bolt and cable end from the battery terminal using a wrench. Lay the cable aside.

2

Locate the tensioner on the front of the engine. Insert the square drive from a 1/2-inch-drive breaker bar into the square hole in the tensioner arm. Rotate the tensioner counterclockwise and slip the belt off the tensioner pulley. Remove the breaker bar.

3

Place a socket and ratchet on the bolt in the center of the tensioner. Rotate the bolt counterclockwise and remove it from the tensioner. Pull the tensioner off the front of the engine and discard it.

4

Position the new tensioner on the engine and install the center bolt. Tighten the bolt to 37 ft.-lbs. with a torque wrench and socket. Place your 1/2-inch-drive breaker bar in the square hole on the new tensioner arm and rotate the tensioner counterclockwise. Slide the serpentine belt onto the new tensioner.

5

Tighten the belt by rotating the tensioner clockwise. Remove the breaker bar from the tensioner. Reattach the negative cable to the battery terminal and tighten the retaining bolt with a wrench.