Repair And Fix it

General Motors has manufactured a series of diesel engines under the Duramax brand since 2001. The primary application for these eight-cylinder, 6.6-liter engines is in heavy trucks requiring low-end torque, like full-size Chevrolet pickups and vans. A Duramax diesel engine uses fuel injectors to send fuel to the cylinders under high pressure. The replacement of the fuel injectors is a relatively simple process, but it also requires the removal of various components to access the injectors.

Instructions

1

Disconnect the negative battery cable with a socket wrench and drain the coolant from the radiator into a suitable container. Detach the electrical connector for the air cooler from the left side of the turbocharger. Unplug the barometric sensors electrical connector.

2

Disconnect the clip for the wiring harness on the engine, and remove the wiring harness bracket with a socket wrench. Unplug the electrical connector for the glow plug. Disconnect the positive crankcase ventilation hose from the left side of the crankcase.

3

Use a socket wrench to disconnect the air cleaner outlet duct from the right side of the engine. Loosen the clamps on the hose to the air intake on the right side of the engine and remove the hose. Disconnect the fuel filter and fuel filter bracket from the right side of the engine. Disconnect the fuel injector control module.

4

Blow compressed air on the fuel lines for the fuel injector. Clean the fuel lines with a shop rag.

5

Detach the fuel send and return lines from the fuel injectors. Unplug the electrical connector from the fuel injector. Disconnect the bolts on the fuel injector bracket, and install injector removal tool J-46594 into one of the bolt holes. Attach a flare nut wrench to the other end of the injector removal tool and pull the flare nut wrench to unseat the fuel injector.

6

Lift the fuel injector from its bore. Discard the O-rings and copper washer for the fuel injector.

7

Mount a new copper washer and O-rings to the new fuel injector. Install the fuel injector, and tighten the bolts on the fuel injector bracket to 22 foot-pounds with a torque wrench. Attach the electrical connector and fuel lines to the fuel injectors. Torque the mounting bolts for the fuel lines to 30 foot-pounds.

8

Complete the installation of the fuel injectors by performing steps 1 through 3 in reverse order. Refill the coolant in the radiator. Start the engine and check for any fluid leaks.

The 1984 GMC S-15 truck with the six-cylinder, 2.8-liter engine is carbureted instead of fuel-injected. As such, the fuel pump on this truck is mounted on the side of the engine block and driven by a cam on the camshaft. If the fuel pump isnt working properly, you can experience poor performance, stalling, and even backfiring. You can change the fuel pump n the 1984 S-15 in about an hour to two hours in your front yard.

Instructions

1

Slide the jack under the front frame cross member, and lift the truck until there is enough room for you to comfortably slide under.

2

Place the jack stands under the frame behind both front wheels, and caully lower the truck onto them. Remove the jack.

3

Slide under the truck, and locate the pump on the lower left front side of the engine. Tag the fuel lines if they are both threaded fittings so you know which line goes where.

4

Remove the fuel lines from the pump. Most fuel pumps will have two threaded fittings; remove these using the flare nut wrenches and turning the fittings counterclockwise. If either of the connections has a rubber hose clamped to it, squeeze the clamp with the pliers, and slide it back on the hose a few inches. Grasp the fuel line, and twist and pull it off the pump nipple.

5

Remove the bolts securing the fuel pump to the block by turning them counterclockwise with the ratchet and socket. Remove the fuel pump by pulling it away from the engine.

6

Clean the block side mating surface of all remnants of the old gasket using the gasket scraper.

7

Apply a thin bead of RTV sealant to both the block and pump mating surfaces. Apply the gasket to block mating surface.

8

Hold the new fuel pump in place, and insert the bolts in the bolt holes, and turn them clockwise by hand. Tighten these bolts to 15 foot-pounds with the ratchet and socket.

9

Reattach the fuel lines to the pump. For threaded fittings, thread the fittings into the new pump by turning them clockwise by hand. Tighten the fittings to 15 foot-pounds using the flare nut wrench. If so equipped, slip the rubber fuel line over the nipple. Squeeze the clamp, and slide it over the nipple.

10

Slide the jack back under the front cross member, and lift the truck off the jack stands. Remove the jack stands, and lower the truck. Start the truck, and verify there are no leaks.

The EGR, or exhaust gas recirculation, valve is a small metal disc bolted to the intake manifold near the carburetor on GMC trucks and vans. The EGR valve draws exhaust gases from the exhaust system and reintroduces them into the intake manifold. Introducing exhaust gases into the combustion chamber helps lower the combustion temperature of the engine, which in turn helps reduce the amount of harmful oxides of nitrogen (NOx) produced by the engine.

Instructions

Removing a GMC EGR Valve

1

Remove the air cleaner housing by unscrewing the wing nut on top of the air cleaner lid and lifting the air cleaner housing straight up until you clear the threaded rod.

2

Locate the EGR valve. It will be bolted to the intake manifold close to the carburetor.

3

Label and disconnect the vacuum line attached to the top of the EGR valve by pulling it off.

4

Remove the bolts that secure the EGR valve to the intake manifold.

5

Lift the EGR valve straight up to remove it from the intake manifold.

6

Use a flat razor blade to clean any gasket material of the EGR valve mounting surface.

7

Inspect the passages below the EGR valve, and use a flat blade screwdriver to clear away any carbon deposits.

8

Vacuum the area around the EGR valve mounting surface. Make sure none of the carbon deposits or loose gasket material is left behind. You dont want it to get sucked into the engine.

Installing an EGR Valve on a GMC

9

Place a new gasket on the EGR valve mounting surface.

10

Lower the new EGR valve into position on the intake manifold.

11

Reinstall the bolts that connect the EGR valve to the intake manifold.

12

Reconnect the vacuum line that attaches to the top of the EGR valve.

13

Reinstall the air cleaner housing by lowering it over the threaded rod above the carburetor and reinstalling the wing nut that secures it.

If you are having problems with your GMC pickup truck, there are two components that need to be checked. The battery on the truck is what fires the electrical current to start the motor. If your battery is dead or corrosion has formed on the battery terminals, your truck will not be able to start. The GMC truck relies on gasoline to run so gas has to be in the fuel tank in order to start the vehicle.

Instructions

1

Pop the hood to your GMC truck and locate the battery to the right of the engine.

2

Look the terminals over for any corrosion. Loosen the terminals with a socket wrench and pull them off of the battery.

3

Use soda and a wire brush to clean the corrosion off of the battery terminals.

4

Reattach the terminals to the batter and try to start the truck.

5

Use jumper cables and another car to jump-start the truck.

6

Leave the truck running for about 5 minutes and then turn it off. Try to restart the truck. If the truck does not restart, replace the battery.

7

Fill the gas tank up with 1 gallon of gas. Try to start the truck. If the truck starts, have a mechanic repair the gas gauge.

The GMC Yukon is a full-size sport utility vehicle. The 1996 model has a standard 8-cylinder, 5.7-liter engine with sequential fuel injection. The fuel pump in this vehicle must maintain a high level of pressure in the fuel system. The fuel pump is mounted in the fuel tank, so you must remove the fuel tank before you can remove the fuel pump.

Instructions

1

Disconnect the negative battery terminal with a socket wrench to prevent the unintentional discharge of fuel. Open the fuel tanks filler cap to relieve the pressure in the fuel tank. Siphon as much fuel from the fuel tank as possible with a hose. Drain the fuel into a gasoline container.

2

Raise the vehicle with a floor jack and support it on jack stands. Disconnect the filler neck and fuel vent tube from the fuel tank. Support the fuel tank with a transmission jack and remove the support straps for the fuel tank with a socket wrench.

3

Lower the fuel tank slightly with the transmission jack so you can disconnect the electrical wiring and fuel hoses to the fuel tank. Disconnect the fuel tank from the vehicle and move it to a work area.

4

Turn the locking ring on the fuel pump assembly counterclockwise with a hammer and brass punch. Remove the locking ring and pull the fuel pump assembly from the fuel tank. Detach the fuel pump from the rest of the fuel pump assembly.

5

Pull the fuel pump away from its bottom support without damaging the rubber insulator or fuel strainer. Pull the fuel pump out of the rubber connector after it is clear of the bottom support.

The washer pumps in a 2000 GMC Jimmy are located on the outside edge of the washer fluid reservoir, next to the right-side fender. These electric pumps draw fluid from the reservoir and force it through rubber tubes that connect to the washer jet nozzles. Over time, the small motors inside these pumps wear out and fail, rendering the washer fluid system inoperable. In order to replace these pumps, the washer reservoir must be removed from the vehicle.

Instructions

Removal

1

Shut down the engine and pop open the hood. Open the washer fluid reservoir cap and draw the fluid out of the reservoir and into a bucket with a hand pump.

2

Disconnect the electrical connectors and hoses from the washer pumps near the bottom of the reservoir.

3

Remove the screw holding the reservoir to the vehicle with a ratchet and metric socket.

4

Lift up on the reservoir and remove it from the vehicle. Remove each from the reservoir by gently pulling and twisting it until it pops loose from its rubber grommet.

Installation

5

Install each new pump into the reservoir by pressing it into the rubber grommet, using a twisting motion, until it is fully seated.

6

Set the reservoir into position inside the engine compartment and reinstall its retaining screw. Torque the screw to 27 inch-pounds, using a torque wrench.

7

Reconnect the hoses and electrical connectors to both pumps.

8

Place a funnel inside the reservoir fill hole and refill the reservoir to the appropriate level, then test the pumps.