Temperature vs Resistance
| ° C | ° F | OHMS |
|---|---|---|
| Temperature vs Resistance Values (Approximate) | ||
| 150 | 302 | 47 |
| 140 | 284 | 60 |
| 130 | 266 | 77 |
| 120 | 248 | 100 |
| 110 | 230 | 132 |
| 100 | 212 | 177 |
| 90 | 194 | 241 |
| 80 | 176 | 332 |
| 70 | 158 | 467 |
| 60 | 140 | 667 |
| 50 | 122 | 973 |
| 45 | 113 | 1188 |
| 40 | 104 | 1459 |
| 35 | 95 | 1802 |
| 30 | 86 | 2238 |
| 25 | 77 | 2796 |
| 20 | 68 | 3520 |
| 15 | 59 | 4450 |
| 10 | 50 | 5670 |
| 5 | 41 | 7280 |
| 0 | 32 | 9420 |
| 5 | 23 | 12300 |
| 10 | 14 | 16180 |
| 15 | 5 | 21450 |
| 20 | 4 | 28680 |
| 30 | 22 | 52700 |
| 40 | 40 | 100700 |
Temperature vs Resistance
Altitude vs Barometric Pressure
| Altitude Measured in Meters (m) | Altitude Measured in Feet (ft) | Barometric Pressure Measured in Kilopascals (kPa) |
|---|---|---|
| Determine your altitude by contacting a local weather station or by using another reference source. | ||
| 4 267 | 14,000 | 56-64 |
| 3 962 | 13,000 | 58-66 |
| 3 658 | 12,000 | 61-69 |
| 3 353 | 11,000 | 64-72 |
| 3 048 | 10,000 | 66-74 |
| 2 743 | 9,000 | 69-77 |
| 2 438 | 8,000 | 71-79 |
| 2 134 | 7,000 | 74-82 |
| 1 829 | 6,000 | 77-85 |
| 1 524 | 5,000 | 80-88 |
| 1 219 | 4,000 | 83-91 |
| 914 | 3,000 | 87-95 |
| 610 | 2,000 | 90-98 |
| 305 | 1,000 | 94-102 |
| 0 | 0 Sea Level | 96-104 |
| 305 | 1,000 | 101-105 |
Altitude vs Barometric Pressure
What Fuel to Use in the United States
In the United States, for best results use Number 2-D diesel fuel year-round, above and below freezing conditions, as oil companies blend Number 2-D fuel to address climate differences. Number 1-D diesel fuel may be used in very cold temperatures when the temperature stays below -18° C (0° F). However, the fuel will produce a power and fuel economy loss. The use of Number 1-D diesel fuel in warm or hot climates may result in stalling, poor starting when the engine is hot and may damage the fuel injection system.
Diesel fuel may foam when filling the tank. This can cause the automatic pump nozzle to shut OFF, even though the tank is not full. If this happens, just wait for the foaming to stop and then continue to fill the tank.
What Fuel to Use in Canada
Canadian fuels are blended for seasonal changes. Diesel Type A fuel is blended for better cold weather starting (when it stays below -18° C (0° F). However, the fuel will produce a power and fuel economy loss. The use of Type A diesel fuel in warmer climates may result in stalling, poor starting. Diesel Type B fuel is blended for temperatures above -18° C (0° F). The emission control system requires the use of diesel fuel with low sulfur, 0.05 percent by weight, content. Both low and higher sulfur fuels will be available in Canada. Only low sulfur diesel fuels are available in the United States. Diesel-powered trucks must be refueled only with low sulfur fuel. Use of fuels with higher-sulfur content will affect the function of the emission components and may caused reduced performance, excessive smoke and unpleasant odor.
Fuel Injector Return Flow and Fuel Pressures
The fuel return from the fuel injectors to the tank will vary based on the API value of the fuel. Measure the Fuel API with the Diesel Fuel Quality Tester. For this reason the Fuel System Diagnosis-High Pressure Side values will vary for identifying a fuel injector or fuel pump concern. Use the following tables when referred to by the diagnostic. The first table is to be used during the initial diagnosis to identify the worst fuel injectors. After the fuel injectors that fail the first part of the test are replaced, the return flow from each fuel injector must be measured again. This is because the fuel system is returning less fuel to the tank, and thus the fuel pressure is higher during the retest. Failure to use the correct table may result in the replacement of good fuel injectors.
| API Rating | Maximum Single Fuel Injector Return Flow | Maximum Fuel Injector Bank Return Flow |
|---|---|---|
| 30-34 | 3 ml | 12 ml |
| 35-39 | 4 ml | 16 ml |
| 40-44 | 5 ml | 20 ml |
Initial Fuel Injector Return Flow Values
| API Rating | Maximum Single Fuel Injector Return Flow | Maximum Fuel Injector Bank Return Flow | Fuel Pressure at cranking speed (FICM Disabled) |
|---|---|---|---|
| 30-34 | 4 ml | 16 ml | 176-180 Mpa |
| 35-39 | 5 ml | 20 ml | 134-178 Mpa 176-180 Mpa |
| 40-44 | 5 ml | 20 ml | 114-135 Mpa |
Retesting Fuel Injector Return Flow Values
Water in Fuel
Sometimes, water can be pumped into the fuel tank along with diesel fuel. This can happen if the service station does not regularly inspect and clean their fuel tanks, or the fuel gets contaminated for the service stations suppliers.
If water is pumped into the fuel tank, a water in fuel light will illuminate. If the water in fuel light illuminates, the excess water must be drained from the fuel system on the vehicle.
Sometimes, water can be pumped into the fuel tank along with diesel fuel. This can happen if the service station does not regularly inspect and clean their fuel tanks, or the fuel gets contaminated for the service stations suppliers.
If water is pumped into the fuel tank, a water in fuel light will illuminate. If the water in fuel light illuminates, the excess water must be drained from the fuel system on the vehicle.
Tool Required
J 44581 Fuel Line Disconnect Tool. See Special Tools and Equipment .
Fuel System Priming
| IMPORTANT | In order for the DURAMAX diesel engine fuel system to work properly, the fuel lines must be full of fuel and contain no air. If air gets into the fuel lines, it will be necessary to prime the fuel system to eliminate the air before operating the vehicle. Air could have entered to system in one of the following ways: The vehicle ran out of fuel. The filter was removed for service or replacement. The fuel lines were removed or disconnected for servicing. The fuel filter water drain cock was opened while the engine was running. If one or more of the above occurred, air has entered the fuel system and you will need to prime the system prior to operating the vehicle. |
- Prior to priming the engine, ensure that the following is complete: There is fuel in the fuel tank. The fuel filter has been installed and properly tightened. The fuel lines are properly connected. The fuel filter is cool to the touch. Any dirt or debris is removed from the fuel filter head and vent valve.
- Open the vent valve by turning the screw counterclockwise several full turns.
- Operate the priming pump until a small amount of fuel seeps from the vent valve. Allow the pump to return upwards between pumps. When fuel is present, the filter is full of fuel and the system should be primed.
- Close the vent valve.
- Clean any fuel which accumulated on the fuel filter.
- Start the engine and allow it to idle for a few minutes.
- Check the filter for leaks.
Tools Required
J 44402 Fuel Tank Sending Unit Wrench
Fuel System Cleaning
Fungi and other microorganisms can survive and multiply in diesel fuel if water is present. The fungi can be present in any part of the fuel handling system. These fungi grow into long strings and will form into large globules. The growths appear slimy and are usually black, green, or brown. The fungi may grow anywhere in the fuel but are most plentiful where diesel fuel and water meet. As the fuel is agitated, when service station tanks are being filled, fungi are distributed throughout the tank and may be pumped into a vehicle.
Fungi use the fuel as their main energy supply and need only trace amounts of water and minerals. As they grow and multiply, they change fuel into water, sludge, acids, and products of metabolism. The most common symptom is fuel filter plugging, however various metal components including the fuel sending unit, pipes, fuel injectors, and injection pump can corrode.
| CAUTION | Avoid physical contact with the biocides in order to avoid personal injury. |
If fungi have caused fuel system contamination, use a diesel fuel biocide to sterilize the fuel system. Do not exceed the dosage recommended on the label. Discontinue the use of a biocide when towing a trailer. It is permissible to have biocide in the fuel when starting to tow, but do not add any biocide while towing.
Steam cleaning may be necessary if most of the fungus growth cannot be removed with biocides.
The presence of water or gasoline in diesel fuel may also cause injection pump and nozzle damage.
This procedure checks for the presence of water and gasoline in diesel fuel that may cause injection pump and nozzle damage.
Remove and inspect the fuel filter element.
- If water, gasoline or fungi/bacteria are not present, end the inspection.
- If water or fungi/bacteria are present, proceed to Cleaning Water from the Fuel System.
- If gasoline is present, proceed to Cleaning Gasoline from the Fuel System.
Cleaning Water from the Fuel System
- Disconnect the negative battery. Refer to «Battery Negative Cable Disconnect/Connect Procedure (Single Battery)»(ref-184144-S12006988322005082200000) or «Battery Negative Cable Disconnect/Connect Procedure (Auxiliary Battery)»(ref-184144-S01033869922005082200000) in Engine Electrical.
- Drain the fuel tank.
- Remove the fuel tank. Refer to «Fuel Tank Replacement (Pickup)»(ref-184139-S25222812662005082200000) or «Fuel Tank Replacement (Cab/Chassis - Front)»(ref-184139-S15896634012005082200000) or «Fuel Tank Replacement (Cab/Chassis - Rear)»(ref-184139-S14458213192005082200000) .
- Remove the sending unit. Refer to «Fuel Sender Assembly Replacement»(ref-184139-S23623806752005082200000) .
- Inspect the fuel tank and the fuel sender for rust, fungi or bacteria. If there is rust, replace the rusted components.
- Clean the inside of the fuel tank and the fuel sender with hot water.
- Use compressed air in order to dry the fuel tank and the fuel sender.
- Disconnect the ends of the following lines: The fuel filter inlet line (both ends) The transfer pump pressure line and suction line (if applicable) The fuel filter outlet line (both ends) The fuel filter drain The fuel return line (both ends)
- Inspect each of the pipes and lines.
- Replace any rusted pipes.
- Clean the inside of the fuel filter housing.
- Dry the fuel filter housing with compressed air.
- Dry the inside of each line with low pressure air.
- Remove the ignition 1 relay from the underhood relay center.
- Install a new fuel filter. Refer to «Fuel Filter Replacement»(ref-184139-S21716815052005082200000) .
- Install the sending unit and the fuel tank. Refer to «Fuel Sender Assembly Replacement»(ref-184139-S23623806752005082200000) and «Fuel Tank Replacement (Pickup)»(ref-184139-S25222812662005082200000) or «Fuel Tank Replacement (Cab/Chassis - Front)»(ref-184139-S15896634012005082200000) or «Fuel Tank Replacement (Cab/Chassis - Rear)»(ref-184139-S14458213192005082200000) .
- Add clean diesel fuel to the primary tank until the tank is 1/4 full.
- Reconnect the following lines: The fuel filter inlet line The fuel filter outlet line The transfer pump pressure and suction (both ends) lines The fuel return line (tank end)
- Connect the fuel filter drain to a line that flows into a clean metal container.
- Connect the batteries.
- Operate the fuel system hand primer at the fuel filter until clean fuel flows from the fuel filter drain into a metal container.
- Close the fuel filter drain and remove the bleeder hose.
- Install a hose on the fuel return line near the glow plug relay, and insert other end into a 7.6 liters (2 gallon) metal container.
- Crank the engine for 30 second time intervals, with 1 minute cool down periods. Continue until 3.8 liters (1 gallon) of fuel has passed into the container.
- Connect the fuel return line.
- Install the ignition 1 relay in the underhood relay center.
- Start and run the engine.
- Stop the engine.
- Clean any fuel spillage from the engine.
- Fill the fuel tank and add a biocide, if needed.
Cleaning Gasoline from the Fuel System
- Drain the fuel tank.
- Fill the fuel tank to 1/4 full.
- Remove the ignition 1 relay from the underhood relay center.
- Loosen the fuel filter drain and connect the filter to a hose that flows into a metal container.
- Operate the fuel system hand primer at the fuel filter until clean fuel flows from the fuel filter drain into the metal container.
- Hand tighten the fuel filter drain and disconnect the hose.
- Install a hose on the fuel return line near the glow plug relay, and insert other end into a 7.6 liters (2 gallon) metal container.
- Crank the engine for 30 second time intervals, with 1 minute cool down periods. Continue until 3.8 liters (1 gallon) of fuel has passed into the container.
- Reconnect the fuel return line.
- Install the ignition 1 relay into the underhood relay center.
- Attempt to start and run the engine for 15 minutes (If engine does not start, operate the hand primer for 30 strokes, or until firm).
- Stop the engine.
- Clean any fuel spillage from the engine.
- Clear the engine of any diagnostic trouble codes (DTCs).
Fuel Feed and Fuel Return Pipe Purge Procedure
- Pump the primer located on top of the fuel filter 30 times or until stiff.
- Attempt to start and run the engine. If the engine does not start, repeat step 1.
- Allow to run for 5 minutes at idle.
- Check for fuel leaks.
- Clear all engine diagnostic trouble codes (DTCs).
Preparing The Fuel Pump
- Hold the fuel pump by the drive gear in a vice with copper jaw liners.
- Loosen the gear nut until the nut is even with the end of the gear shaft.
- Remove the gear from the tapered shaft of the pump.
- Separate the pump and adapter by removing the three bolts and spacers.
- Inspect the O-ring for damage on pump adapter and replace, if necessary. Lubricate the O-ring with clean engine oil.
- Clean all mating surfaces.
- Install the adapter on the pump.
- Using the three bolts and spacers, reassemble the pump. Tighten: Tighten the bolts to 20 N.m (15 lb ft).
- Replace the gear and nut. Tighten: Tighten nut to 70 N.m (52 lb ft).
J 44639 Fuel Injector Puller
Exhaust Gas Recirculation (EGR) System Cleaning
| CAUTION | Avoid breathing fumes and swallowing EGR exhaust deposits when removing components for cleaning as bodily injury may result. |
- Remove the exhaust gas recirculation (EGR) valve. Refer to «Exhaust Gas Recirculation (EGR) Valve Replacement»(ref-184139-S37431876232005082200000) .
- Depress the pintle several times using a pencil eraser or other suitable soft instrument. The pintle should move in and out smoothly. Replace the valve if the valve exhibits tendencies to stick.
- Try to rotate the EGR valve electrical connector housing. Repeat for the coil housing. Replace the valve if the valve exhibits any looseness. Inspect the EGR valve pintle and seat for deposits. Use a cloth or other suitable soft device to remove the deposits. Remove all loose particles. Replace the valve if the deposits are such that the pintle to base interface cannot be cleaned adequately to allow the pintle to seal against the seat. Damage to the powdered metal EGR valve base occurs if cleaned with solvents, sharp tools, wire brush or wheel, or sand blasting. Cleaning by these methods is not recommended.
- Clean the passages with a wire brush. Remove all loose particles.
- Install the EGR valve. Refer to «Exhaust Gas Recirculation (EGR) Valve Replacement»(ref-184139-S37431876232005082200000) .
Control Module Communications
The control module system has a computer, the engine control module (ECM), to control fuel delivery, timing, and some emission control systems. The control module system monitors a number of engine and vehicle functions and controls the following operations through the fuel injection control module (FICM)
- Fuel rail pressure
- Fuel injector
- Fuel injector pulse width
The diesel engine control module (ECM), located in the engine compartment, is the control center of the control module system. The engine control module used on the electronic fuel injected 6.6L diesel is referred to as a ECM.
The ECM constantly looks at the information from various sensors, and controls the systems that affect vehicle performance. The ECM performs the diagnostic function of the system. The ECM can recognize operational problems, alert the driver through the MIL - Service Engine Soon, and store one or more diagnostic trouble codes (DTCs) which identify the problem areas to aid the technician in making repairs. See the specific diagnosis procedure for more information.
Aftermarket (Add-On) Electrical And Vacuum Equipment
Any equipment installed on a vehicle after leaving the factory that connects to the electrical or vacuum systems of the vehicle defines aftermarket (Add-On) electrical and vacuum equipment. The vehicle design makes no allowances for this type of equipment.
Note. Do not attach add-on vacuum operated equipment to this vehicle. The use of add-on vacuum equipment may result in damage to vehicle components or systems.
Note. Connect any add-on electrically operated equipment to the vehicle's electrical system at the battery (power and ground) in order to prevent damage to the vehicle.
The add-on electrical equipment, even when installed to these strict guidelines, may still cause the powertrain system to malfunction. This may also include any equipment which is not connected to the electrical system of the vehicle such as portable telephones and radios. Therefore, the first step in diagnosing any powertrain problem is to eliminate all of the aftermarket electrical equipment from the vehicle. After this is done, if the problem still exists, diagnose the problem in the normal manner.
Engine Controls Information
The driveability and emissions information describes the function and operation of the control module. The emphasis is placed on the diagnosis and repair of problems related to the system.
Engine Components, Wiring Diagrams, and Diagnostic Trouble Code (DTC) tables
- The Component Locations
- The Wiring Diagrams
- The Control Module Terminal End View and Terminal Definitions
- The Diagnostic System Check - Engine Controls
- The Diagnostic Trouble Code (DTCs) tables
The Component System includes the following items
- The component and circuit description
- The On-vehicle service for each subsystem
- The Functional checks with the diagnostic tables
- How To Use Electrical Systems Diagnostic Information
The DTCs also contain the diagnostic support information containing the circuit or the system information, and helpful diagnostic information.
Connectors and Terminals
In order to prevent shorting between opposite terminals, use care when probing a connector and when replacing terminals. Damage to the components could result.
Always use jumper wires between connectors for circuit checking.
Never probe through the Weather-Pack seals.
The J 35616 Connector Test Adapter Kit, or the equivalent, contains an assortment of flexible connectors used in order to probe the terminals during the diagnosis. The fuse remover and the BT-8616 Test Tool, or the equivalent, is used for removing a fuse and to adapt the fuse holder to a meter for diagnosis.
Open circuits are often difficult to locate by sight because oxidation or terminal misalignment are hidden by the connectors. Merely wiggling a connector on a sensor or in the wiring harness may temporarily correct the open circuit. Oxidized or loose connections may cause intermittent problems.
Be certain the type of connector and terminal before making any connector or terminal repair. Weather-Pack and Com-Pack III terminals look similar, but are serviced differently.
Scheme 285
The accelerator pedal position (APP) system along with the vehicle electronics and components is used to calculate and control the amount of acceleration and deceleration via fuel injector control. This eliminates the need for a mechanical cable attachment from the accelerator pedal to a throttle body.
The APP system includes, but is not limited to, the following components
- The accelerator pedal position (APP) sensor assembly
- The engine control module (ECM)
Accelerator Pedal Position (APP) Sensor
The accelerator pedal position (APP) sensor is mounted on the accelerator pedal control assembly. The sensor is made up of 3 individual sensors within one housing. Three separate signal, low reference, and 5-volt reference circuits are used in order to interface the accelerator pedal sensor assembly with the ECM. Each sensor has a unique functionality to determine pedal position. The ECM uses the APP sensor to determine the amount of acceleration or deceleration desired by the person driving the vehicle. The APP sensor 1 voltage should increase as the accelerator pedal is depressed, from below 1.0 volt at 0 pedal travel to above 2 volts at 100 percent pedal travel. APP sensor 2 voltage should decrease from above 4 volts at 0 pedal travel to below 3.0 volts at 100 percent pedal travel. APP sensor 3 voltage should decrease from above 3.8 volts at 0 percent pedal travel to below 3.3 volts at 100 percent pedal travel.
Fuel Level Sensor
The fuel level sensor consists of a float, a wire float arm, and a ceramic resistor card. The position of the float arm indicates the fuel level. The fuel level sensor contains a variable resistor which changes resistance in correspondence with the amount of fuel in the fuel tank. The ECM sends the fuel level information via the Class II circuit to the instrument panel (IP) cluster. This information is used for the IP fuel gage and the low fuel warning indicator, if applicable. The ECM also monitors the fuel level input for various diagnostics.
Fuel Strainer
The fuel strainer attaches to the lower end of the fuel sender. The fuel strainer is made of woven plastic. The functions of the fuel strainer are to filter contaminants and to wick fuel. The fuel strainer is self-cleaning and normally requires no maintenance. Fuel stoppage at this point indicates that the fuel tank contains an abnormal amount of sediment.
Scheme 286
On vehicles equipped with dual fuel tanks, an electric fuel pump is located on the left frame rail. This fuel pump is powered by the fuel pump relay that is controlled by the ECM. Fuel is transferred from the auxiliary fuel tank to the primary fuel tank in order to ensure all of the usable fuel volume is available to the fuel injection pump.
Scheme 287
The fuel injection pump is a mechanical high pressure pump. The fuel injection pump is located below the intake manifold. Fuel is pumped to the fuel rails at a specified pressure. Fuel pressure is regulated by a valve on the inlet of the fuel pump, controlled by the ECM. Excess fuel from the fuel injection pump returns to the fuel tank through the fuel return pipe and a fuel cooler.
Scheme 288
The fuel filter is located on the rocker cover. The paper filter element traps particles in the fuel that may damage the fuel injection system.
Fuel Feed and Return Pipes
The fuel feed pipe carries fuel from the fuel tank to the fuel injector control module. The fuel return pipe carries fuel from the fuel rail assemblies back to the fuel tank. The fuel pipes consist of 2 sections
- The rear fuel pipe assemblies are located from the top of the fuel tank to the chassis fuel pipes. The rear fuel pipes are constructed of steel with sections of rubber hose covered with braiding.
- The chassis fuel pipes are located under the vehicle and connect the rear fuel pipes to the fuel rail pipes. These pipes are constructed of steel with sections of rubber hose covered with braiding.
Quick-Connect Fittings
Quick-connect fittings provide a simplified means of installing and connecting fuel system components. The fittings consist of a unique female connector and a compatible male pipe end. O-rings, located inside the female connector, provide the fuel seal. Integral locking tabs inside the female connector hold the fittings together.
Fuel Pipe O-Rings
O-rings seal the connections in the fuel system. Fuel system O-ring seals are made of special material. Service the O-ring seals with the correct service part.
Scheme 289
The fuel junction block is located between the left and right fuel rail assemblies. The fuel junction block consists of the following components
- The fuel rail pressure sensor
- The fuel pressure relief valve
The fuel rail pressure sensor gives the ECM an indication of fuel pressure. The ECM uses this information to regulate fuel pressure, by commanding the fuel pressure regulator open or closed on the inlet of the fuel injection pump.
The fuel pressure relief valve opens only to prevent excessive pressure in the event of a malfunction. Fuel from the fuel pressure relief valve is returned to the fuel tank.
Scheme 290
The left and right fuel rail assemblies attach to the cylinder heads. The fuel rail assemblies distribute pressurized fuel evenly to the fuel injectors
Scheme 291
A fuel injector is a solenoid device, controlled by the fuel injection control module (FICM), that meters pressurized fuel to a single engine cylinder. The fuel injectors are located under the rocker covers. The ECM energizes the low-impedance injector solenoid to open a normally closed valve. Fuel pressure is released from above the fuel injector pintle, and is returned to the fuel tank. The difference in fuel pressure above and below the pintle causes the pintle to open. Fuel from the fuel injector tip is sprayed directly into the combustion chamber on the compression stroke of the engine.
Scheme 292
The fuel system cooler (1) is located in front of the primary fuel tank. The fuel system cooler cools the fuel before it is returned to the fuel tank.
Glow Plugs
The glow plugs are heaters in each of the cylinders that turn ON when the ignition switch is turned to the Run position prior to starting the engine. They remain pulsing a short time after starting, then they are turned OFF.
A Wait to Start lamp on the instrument panel provides information on engine starting conditions. The Wait to Start lamp will not illuminate during post-start glow plug operation.
Glow Plug Relay/Controller
The glow plug relay is a solid state device which operates the glow plugs on Federal Emissions Vehicles. The glow plug controller is a solid state device which operates the glow plugs on California Emissions vehicles. Both components perform the same function of turning ON the glow plugs based on ECM commands
The glow plug controller or relay is connected to the following circuits
- The fuel heater ignition 1 voltage circuit
- The battery voltage circuit
- The glow plug enable circuit located between the ECM and the glow plug relay or controller
- The engine ground circuit
- The glow plug supply voltage circuit located between the glow plug relay/controller and the glow plugs.
On the California Emissions vehicles, the glow plug diagnostic circuit connects directly from the ECM to the glow plug controller. On Federal emissions vehicles, the glow plug diagnostic circuit is spliced to the glow plug enable circuit after the relay.