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Old 03-31-2014, 07:43 AM   #6 (permalink)
BigWoodyWag
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Here is the service info,

DTC Descriptors
DTC P0087: Fuel Rail Pressure (FRP) Too Low

DTC P0088: Fuel Rail Pressure (FRP) Too High


Diagnostic Fault Information
Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure.

Circuit
Short to Ground
High Resistance
Open
Short to Voltage
Signal Performance

FRP Sensor 5-Volt Reference
P0117, P0522, P0652, P0700
P0087, P0191, P0192, P0700
P0193
P0533, P0653
--

FRP Sensor Signal
P0192
P0191
P0193
P0193
--

Fuel Pressure Regulator Solenoid Supply Voltage
P0088, P0090
P0088
P0090
P0087, P0191, P2510
--

Fuel Pressure Regulator Solenoid Control
P0088, P0090
P0088
P0090
P0090
--


Circuit/System Description
The fuel injection pump supplies high pressure fuel to the fuel injection rails, and then to the fuel injectors through high pressure pipes. The fuel rail pressure (FRP) sensor is a three wire sensor mounted in the right fuel injection rail. The FRP sensor uses a 5-volt reference circuit , a signal circuit, and a low reference circuit to monitor fuel rail pressure. This information is sent to the engine control module (ECM) to assist in the fueling of the engine.

Conditions for Running the DTC
P0087
• DTCs P0090, P0192, P0193 are not set.

• The engine is running.

P0088
• DTCs P0087, P0192, P0193 are not set.

• The engine is running.

Conditions for Setting the DTC
P0087
• The actual FRP is more than 15 MPa (2,176 psi) below the desired FRP.

OR

• The actual FRP is less than 22.5 MPa (3,263 psi).

P0088
• The actual FRP is more than 20 MPa (2,900 psi) above the desired FRP.

OR

• The actual FRP is more than 189 MPa (27,412 psi)

Action Taken When the DTC Sets
DTCs P0087 and P0088 are Type A DTCs.

Conditions for Clearing the MIL/DTC
DTCs P0087 and P0088 are Type A DTCs.

Diagnostic Aids
P0087
• Gasoline contamination of the fuel may cause this DTC to set. Refer to Contaminants-in-Fuel Diagnosis .

• When ambient temperatures are below 0°C (32°F), the fuel tank pickup screen may be iced over from water in the fuel tank.

• When power enhancing devices have been attached to the fuel rail pressure sensor circuits, this DTC may set and adversely effect the fuel system components.

• If the fuel pressure valve is not torqued correctly, the valve will leak fuel into the fuel return system causing this DTC to set. The fuel pressure relief valve uses a bite type seal, and proper torque is essential for valve to rail sealing. Refer to Fastener Tightening Specifications .

• A sticking FRP regulator may cause this DTC to set.

• High fuel injector return flow may cause this DTC to set.

• The addition of fuel system enhancements, such as auxiliary fuel tanks or add on fuel filters may relate to driveability complaints.

P0088
• Driveability concerns may not occur with this DTC present.

• If the fuel system pressure is actually too high, a fuel knock and smoke condition will exist.

• A sticking FRP regulator may cause this DTC to set.

Reference Information
Schematic Reference
Engine Controls Schematics

Electrical Information Reference

• Circuit Testing

• Connector Repairs

• Testing for Intermittent Conditions and Poor Connections

• Wiring Repairs


DTC Type Reference
Powertrain Diagnostic Trouble Code (DTC) Type Definitions

Special Tools Required
J 44638 Vacuum Gage

Circuit/System Verification
With engine running, observe the Actual Fuel Rail Pressure parameter with a scan tool. A normal reading would be approximately 40 MPa (5,802 psi) with the engine cold, and 30 MPa (4,351 psi) at operating temperature. Inspect the fuel supply lines for damage between the fuel tank and the fuel injection pump.

Circuit/System Testing
P0087
If DTC P0090, P0168 or P0191 is also set, refer to Diagnostic Trouble Code (DTC) List - Vehicle .
Ignition ON for 90 seconds, verify the scan tool FRP Regulator Command parameter is less than 20 percent.
⇒ If greater than the specified range, replace the ECM.

Attempt to start the engine.
⇒ If the engine does not start, refer to Engine Cranks But Does Not Run .

Install the J 44638 to the fuel rail service port and slowly increase the engine speed until reaching wide open throttle (WOT). Vacuum should be less than 5 inches Hg of vacuum.
⇒ If more than 5 inches Hg of vacuum was present during engine speed increase, replace the fuel filter and inspect for fuel system restrictions. Refer to Contaminants-in-Fuel Diagnosis .

⇒ If no restriction were found, test for high fuel return flow. Refer to Fuel System Diagnosis - High Pressure Side

With the engine idling or at an idle, command the fuel pressure control to 180 MPa (23,206 psi) with a scan tool. Observe the Actual Fuel Rail Pressure parameter. The actual fuel pressure should be the same as the commanded pressure.
⇒ If the Actual Fuel Rail Pressure is less than 145 MPa (21,030 psi), inspect the inlet connection of the left fuel injection rail for debris, and replace the fuel injection pump if debris was found. Clean the fuel system of all debris.

⇒ If debris was not found and the Actual Fuel Rail Pressure is less than 145 MPa (21,030 psi), refer to Fuel System Diagnosis - High Pressure Side .

Important: If the fuel temperature is near 121°C (250°F) during the duplication of the complaint, or in the Failure Records for this DTC, inspect for a restriction in the fuel cooler air flow or the fuel heater always ON. Refer to Fuel Heater Always On .

Operate the vehicle within the conditions for which the customer complaint occurs while observing the J 44638 . You may also operate the vehicle within the conditions that you observed in the Freeze Frame/Failure Records.
⇒ If the vacuum was more than 12 inches Hg of vacuum at any time in the operating range, inspect for kinked or restricted fuel supply lines.

Operate the vehicle within the conditions for which the customer complaint occurred. Observe the Actual fuel Rail Pressure and Desired Fuel rail Pressure parameters with a scan tool. Fuel pressures should be the same for both parameters.
⇒ If the Actual Fuel Rail Pressure is less than the Desired Fuel Rail Pressure, refer to Fuel System Diagnosis - High Pressure Side .

⇒ If fuel system tests normal, refer to Diagnostic Aids.

P0088
Start the engine and operate the vehicle within the Conditions for Running the DTC. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records.
Observe the Actual Fuel Pressure parameter with a scan tool. The actual pressure should be 30 MPa (4,352 psi) with the engine idling at operating temperature.
Command the fuel pressure with a scan tool, incrementing through the entire fuel pressure range. The fuel pressure should increment and stabilize through the entire fuel pressure range with actual and desired fuel pressure within 2 MPa (290 psi) of each other.
⇒ If the pressure difference between the actual and desired pressure are more than 2 MPa (290 psi), test the solenoid supply voltage circuit and the solenoid control circuit for high resistance or a short to ground. If the circuits test normal, replace the FRP regulator.

⇒ If the pressure difference between the actual and desired pressure is less than 2 MPa (290 psi), refer to Diagnostic Aids.

Repair Instructions
Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

Fuel Pressure Regulator Replacement




Diagnostic Instructions
• Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure.

• Review Strategy Based Diagnosis for an overview of the diagnostic approach.

• Diagnostic Procedure Instructions provides an overview of each diagnostic category.

Circuit/System Description
High Pressure System
The fuel injection pump at the front of the engine valley includes a fuel supply pump and a high-pressure pump. Fuel is drawn by the fuel supply pump from the primary fuel tank and delivered to the high-pressure pump. The pump is engine-driven by the camshaft gear. High pressure fuel is regulated by the fuel pressure regulator mounted on the fuel injection pump. From the high-pressure pump, the fuel moves to the left and right fuel rails through high pressure metal lines. Each fuel rail distributes high pressure fuel to one bank of 4 fuel injectors. The fuel pressure relief valve is location on the left rail, and relieves excessive fuel pressure which returns to the fuel tank .

Return System
The fuel return system routes fuel from the fuel injectors, the pressure relief valve, and the fuel injection pump. The return fuel travels to the fuel cooler and then to the fuel tank. This fuel is used to cool and lubricate the injection pump and the injectors.

Diagnostic Aids
• The fuel return volumes vary based on the American Petroleum Institute (API) rating of the diesel fuel.

• A fuel injector may have high fuel return flow only at higher engine temperatures.

Reference Information
Special Tools Required

• J 45873 Fuel Return Volume Test Kit

• J-45873-30 Injector Flow Test Adapter


Circuit/System Verification
With the engine running at idle the Actual Fuel Pressure should be close to the Desired Fuel Rail Pressure. During engine cranking the Actual Fuel Pressure should be at least 10 MPa. Inspect the fuel return hoses and lines for external leaks or damage.

Circuit/System Testing
Important: If you were not referred to this test from another diagnostic, do not perform this procedure. Only perform this test when the fuel is more than 18°C (65°F).

Important: Before replacing the fuel pressure relief valve, ensure that the break-away torque is within specifications. Refer to Fastener Tightening Specifications .

Remove the fuel pressure relief valve return hose and plug the hose to prevent fuel leakage.
Install a section of rubber fuel hose on the fuel pressure relief valve connection and place loose end of hose into a clean fuel container.

Important: Fuel that is contaminated with gasoline may cause permanent damage to the fuel pressure relief valve. Refer to Contaminants-in-Fuel Diagnosis .


• If the engine cranks but does not start, crank engine for 15 seconds. Observe for fuel leaking from fuel pressure relief valve.

⇒ If fuel leaks from the fuel pressure relief valve, replace the pressure relief valve. Refer to Fuel Pressure Relief Valve Replacement .

• If the engine starts and runs, idle the engine while commanding the fuel rail pressure to 180 MPa with a scan tool. Observe for fuel leaking from fuel pressure relief valve.

⇒ If fuel leaks from the fuel pressure relief valve, replace the pressure relief valve. Refer to Fuel Pressure Relief Valve Replacement .

Important: Always replace the fuel return hose retaining clips on the fuel injectors with new clips after removing.

Remove the fuel return hose from the fuel injectors of the right cylinder bank. Refer to Fuel Injection Fuel Return Pipe Replacement - Right Side .
Connect the yellow hoses from the J 45873 to the J-45873-30 .
Connect the J-45873-30 with yellow hoses to each fuel injector return port of the right cylinder bank, and install the retaining clips.
Install the 4 yellow hoses in the J 45873 graduated cylinders in numerical order.
Connect the fuel return hoses to the J-45873-30 to prevent leakage.
⇒ If the engine starts and runs, idle the engine until fuel start dripping into all the graduated cylinders and yellow hoses are full of fuel.

Important: The engine cranking speed must be more than 150 RPM during the cranking portion of this test.

⇒ If the engine does not start, crank the engine in 15-second intervals, with 1 minute cooling time between intervals, until fuel starts to flow into all of the graduated cylinders.

Elevate the 4 yellow hoses to retain the fuel in the hoses, and empty the 4 graduated cylinders into a suitable container.
Install the 4 yellow hoses in the J 45873 graduated cylinders in numerical order.
⇒ If the engine starts and runs, idle the engine for 15 seconds.

⇒ If the engine does not start, crank the engine for 15 seconds.

Important: During replacement of the injectors, inspect the inlet and outlet fittings for corrosion or contamination. Refer to Contaminants-in-Fuel Diagnosis .

Measure the quantity of fuel in each of the graduated cylinders. Refer to Fuel System Specifications for the desired quantities.
⇒ If high return flows were recorded, replace those fuel injectors that had high return flow and retest the fuel return flow, referring to Fuel System Specifications . Replace any additional high return flow injectors and proceed to the next number step.

Install and connect all fuel system components that were previously removed or disconnected.
Remove the fuel return pipes from the fuel injectors of the left cylinder bank and repeat the fuel return flow test previously preformed on the right cylinder bank .
⇒ If high return flows were recorded, replace those fuel injectors that had high return flow and retest the fuel return flow, referring to Fuel System Specifications . Replace any additional high return flow injectors and proceed to the next number step.

Install and connect all fuel system components that were previously removed or disconnected.
Start and idle the engine. You may have to prime the fuel system before the engine will start. Command the fuel pressure control to 180 MPa with a scan tool. The actual fuel pressure should be the same as the commanded pressure.
⇒ If the engine does not start or the fuel pressure is less than 145 MPa when commanded, replace the fuel injection pump.

Command the fuel pressure control to 180 MPa with a scan tool. The fuel pressure should be able to reach 145 MPa when commanded.
⇒ If the fuel pressure is less than the specified value, refer to Fuel System Diagnosis .

Operate the vehicle in order to verify the repairs.
Repair Instructions
Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

• Fuel Injection Pump Replacement

• Fuel Pressure Relief Valve Replacement

• Fuel Injector Replacement



Removal Procedure




Remove the air intake pipe. Refer to Air Intake Pipe Replacement .
Disconnect the air conditioning (A/C) compressor clutch electrical connector.
Disconnect the A/C cut out switch electrical connector.
Remove the A/C compressor bolts.
Remove the generator. Refer to Generator Replacement .
Reposition the A/C compressor (with the hoses attached) to the right side of the engine compartment.



Disconnect the main engine electrical harness connectors. Lift up on the latches (1) in order to disconnect the connectors.
Open the harness clip (2).
Remove the main engine electrical harness connectors.



Remove the main engine harness electrical connector bolts.
Remove the main connectors from the bracket.



Disconnect the engine coolant temperature (ECT) sensor electrical connector.
Remove the water outlet tube. Refer to Water Outlet Tube Replacement .



Disconnect the fuel temperature sensor electrical connector.



Disconnect the fuel pressure regulator electrical connector (1).



Disconnect the oil level sensor harness electrical connector.



Reposition the distribution block hose clamps.
Remove the distribution block hoses from the distribution block.



Clean the fuel pressure regulator and high pressure injection pump thoroughly with solvent, such as GM P/N 12377981 (Canadian P/N 10953463) or equivalent.
Remove the exhaust gas recirculation (EGR) coolant pipe bolts.
Loosen the EGR coolant pipe clamp and position the hose aside.
Using compressed air, thoroughly blow dry the regulator and pump.
Remove the 3 fuel pressure regulator screws (1) using a T25 TORX®.



Remove the fuel pressure regulator (1).
If dirt or debris is found in the bore or seating surfaces of the fuel injection pump, perform the following:
• Place a clean rag over the bore on order to collect the excess fuel.

• Bump the engine over in order to flush any debris out of the regulator bore.

Installation Procedure
Important: If the pressure regulator is being re-used, check the O-rings for damage. If the O-rings are damaged, install NEW O-rings.





Lubricate and install NEW O-rings onto the regulator. Lubricate the O-rings with clean, NEW engine oil.
Important: If the regulator is installed at an angle the O-rings may be damaged, resulting in possible fuel leakage.

Install the fuel pressure regulator (1).
Notice: Refer to Fastener Notice in the Preface section.





Install the 3 fuel pressure regulator screws (1) using a T25 TORX®.
Tighten

• Tighten the screws a first pass to 4 N·m (35 lb in).

• Tighten the screws a final pass to 7 N·m (62 lb in).





Position the EGR coolant pipe clamp and install the coolant pipe to the thermostat housing.
Install the EGR coolant pipe retaining bolts.
Tighten
Tighten the EGR coolant pipe bolts to 21 N·m (15 lb ft).

Install the distribution block hoses to the distribution block.
Position the distribution block hose clamps.



Connect the oil level sensor harness electrical connector.



Connect the fuel pressure regulator electrical connector (1).



Connect the fuel temperature sensor electrical connector.



Install the water outlet tube. Refer to Water Outlet Tube Replacement .
Connect the ECT sensor electrical connector.



Install the main connectors to the bracket.
Install the main engine harness electrical connector bolts.
Tighten
Tighten the bolts to 21 N·m (15 lb ft).





Connect the main engine electrical harness connectors.
Push down on the latches (1) in order to connect the connectors.
Close the harness clip (2).



Position the A/C compressor.
Install the A/C compressor bolts.
Tighten
Tighten the bolts to 50 N·m (37 lb ft).

Connect the A/C cut out switch electrical connector.
Connect the A/C compressor clutch electrical connector.
Install the generator. Refer to Generator Replacement .
Install the air intake pipe. Refer to Air Intake Pipe Replacement .
Prime the fuel system. Refer to Fuel System Priming .
Start the engine. If the engine stalls, repeat the above step.


Contaminants-in-Fuel Diagnosis
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. Service station tanks may contain fungi that could be pumped into a vehicle during refueling.

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 fuel system components including fuel sender assembly, pipes, fuel injectors, and fuel 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 due to possible engine power loss. It is permissible to have biocide in the fuel when starting to tow, but do not add any biocide while towing.

Water in fuel will also create drivability concerns and loss of engine power. If water is present in the fuel system , the fuel cannot cool and lubricate the components, causing overheating , rust and corrosion. This can result in component failure. Water can enter the fuel system in several ways, either through a contaminated refueling source, or through long term condensation the vehicle fuel tanks.

Like fungi and water, gasoline contamination will cause drivability concerns and a possible hard starting or a no start condition if the overall content is large enough. Gasoline raises the API rating and reduces cooling and lubrication, resulting in possible component failure.

Inspecting for Fuel Contaminants
Test the fuel specific gravity and record the results. Refer to Fuel System Specifications .
Remove the fuel filter and inspect the inside area of the fuel filter for dirt, water deposits, or other debris.
Drain the fuel filter into an approved clear container and allow the contents to settle. Observe the container for contaminant separation.
Remove the water-in-fuel sensor from the bottom of the fuel filter and inspect inside the filter for rust deposits, dirt, or other debris.
Important: The presence of water or gasoline in diesel fuel may also cause damage to other fuel system components.

If contaminants are present in the fuel or in any of the inspected areas, remove the fuel lines to the injectors and inspect the fuel injector return outlets and feed inlets for rust or corrosion.
⇒ Replace the fuel injectors if rust or corrosion is present. Refer to Fuel Injector Replacement and Fuel System Cleaning .

⇒ If rust or corrosion was not present in the injectors, but fungi, water or gasoline was present, refer to Fuel System Cleaning and attempt to start and run the engine after procedure is completed
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