Procedure for Diagnosing the HEUI Fuel System {7729} Caterpillar

Procedure for Diagnosing the HEUI Fuel System {7729}

Usage:

Truck Engines:: 3116 (S/N: 8WL1-UP); 3126 (S/N: 1WM1-UP); 3126B (S/N: 1AJ1-UP; BKD1-UP; 7AS1-UP; 8SZ1-UP; 8YL1-UP); 3126E (S/N: CKM1-UP; CRP1-UP; 9SZ1-UP)
Marine Engines:: 3126B (S/N: 9ZF1-UP; 3GS1-UP)

Introduction

Use the steps that follow to check the operation of the HEUI fuel system. Complete the pages and return the pages with any of the parts requested through the part return system.

Symptoms

The following symptoms may occur if there is a problem with the HEUI fuel system:

The engine cranks but the engine will not start.
The engine runs rough.
The engine is Erratic or Unstable at idle or running.
Low power
The following fault codes might be currently active codes or logged event codes: 164-11, 164-00 and 164-02

Answer the following questions. Return the answers with the fuel system component.

Connect Caterpillar Electronic Technician, (Cat ET) and print the Lifetime Total and ECM configuration.

Turn the engine off. Turn the ignition switch to the on position but do not start the engine. Are there active diagnostic codes?
____ Yes - Refer to your application Troubleshooting Guide.
____ No - Proceed to Step 3.

Check the engine oil level.
If the engine oil level is low add oil to the engine.
When the oil level is correct Proceed to Step 4.

Does the engine start?
____ No - Proceed to ""Engine Cranks but will Not Start" ".
____ Yes - Proceed to ""Engine Starts" ".

Engine Cranks but will Not Start

Your answers indicated that your engine oil level is satisfactory. Do not replace the Injection Actuation Pressure Sensor IAP Sensor at this time.

Connect Cat ET to your engine. Observe the Injection Actuation Pressure and Engine RPM when the engine is cranking.
________ Record the actual Injection Actuation Pressure.
________ Record the observed engine speed.
1. Is the Injection Actuation Pressure above 6 MPa (870 psi) for 3126B and 3126E? Is the Injection Actuation Pressure above 5 MPa (725 psi) for 3126 and 3116?
  ____ Yes - The HEUI system is functioning correctly. Refer to Troubleshooting Guide, "Engine Cranks but will Not Start".
  ____ No - Proceed to Step 2.

Disconnect the high pressure oil line from the cylinder head and install the 8T-0852 Pressure Gauge . Crank the engine and record the oil pressure.
Note: The pressure readings may vary from gauge to gauge.
________ Observed pressure reading
________ Observed RPM
________ Observed Injection Actuation Output Percent
1. Is the oil pressure above 27.5 MPa (4000 psi)?
  ____ Yes - Proceed to Step 6.
  ____ No - Proceed to Step 3.

Install a 219-2368 Plug and 9X-1484 Seal Kit , or a new Injection Actuation Pressure Control Valve (IAPCV) and perform the pressure test.
________ Observed Pressure
1. Is the oil pressure above 27.5 MPa (4000 psi) using the 219-2368 Plug ?
  ____ Yes - The HEUI pump is ok, replace the IAPCV and proceed to Step 3.b. If the problem continues contact technical support.
  ____ No - Install the original IAPCV and proceed to Step 4.
1. Is the oil pressure above 27.5 MPa (4000 psi) using the New IAPCV?
  ____ Yes - Stop, the problem is solved, Do Not proceed with the test. If the problem continues contact technical support.
  ____ No - Install the original IAPCV and proceed to Step 4.

Remove the HEUI pump and inspect the drive gear. Is the gear tight? A loose gear may move freely on the shaft.
____ Yes - Replace the HEUI pump. Stop, problem solved do not proceed with the test. If the problem persists contact technical support.
____ No - Proceed to Step 5.

Does the HEUI pump turn freely?
____ Yes - Drive gear has loosened. Tighten the gear to 110 ± 14 N·m (80 ± 10 lb ft). Reinstall the original IAPCV. Checking the pressure with the procedure in Step 3 will indicate if the problem is resolved. Replace the HEUI pump if the problem still exists.
____ No - The pump has failed. The pump failure has caused the drive gear to loosen. Replace only the HEUI pump. Reinstall the following original parts: drive gear, fuel transfer pump and IAPCV. Stop, problem solved do not proceed with the rest of the test. If the problem persists contact technical support.

Remove the valve cover and inspect the HEUI system for oil leaks. Look around the injector bores for any signs of oil leakage. Inspect the injector spill ports for excessive oil. All six injectors should spill the same amount of oil while the engine is being cranked. Are there leaks around the injector O-rings or is there excessive oil coming from the injectors?
____ Yes - Replace the O-ring on the injector or replace the damaged injector.
____ No - Call technical support for assistance.

Engine Starts / HEUI Complaint

Connect Cat ET and start the engine. Check for the following types of codes:

Active Diagnostic Codes
Logged Diagnostic Codes
Event Codes

Show/hide table

Table 1
Occurrences of 164-XX
	Code	First Hour of Occurrence	Last Hour of Occurrence
Active Codes
Logged Codes
Event Codes

Show/hide table

Table 2
Other Codes
	Code	First Hour of Occurrence	Last Hour of Occurrence
Active Codes
Logged Codes
Event Codes

Are there any active 164-02 fault codes?
____ Yes - Proceed to Step 2.
____ No - Proceed to Step 3.

Are there any 164-11 or 164-00 logged or active diagnostic codes?
____ Yes - Proceed to Step 3.
____ No - Refer to Troubleshooting, "Injection Actuation Pressure Sensor - Test".

Evaluate the Quality of the Oil.
Extended oil change intervals may cause elevated levels of soot in the engine oil. The elevated levels of soot may also deplete the additive package of the oil. This can affect the operation of the HEUI high pressure oil system.
The formulas require information to be collected from Cat ET. Enter the values from Cat ET for the total distance and for the total fuel used.
English
Total Distance ________ (miles) / Total Fuel ________ (gallons) = Overall MPG ________ Overall MPG ________ x 50 x Oil Pan Capacity in Quarts ________ = Recommended Interval ________
Metric
Total Distance________ (kilometers) / Total Fuel ________ (liter) = Overall KPL ________ Overall KPL ________ x 200 x Oil Pan Capacity in Liters ________ = Recommended Interval ________
Note: The recommended oil pan capacities are for truck engines. The shallow oil pan capacity is 21 L (22 qt). The deep oil pan capacity is 28 L (30 qt).

What is the Change Interval that is currently being used by the owner?
________ Change Interval
________ Miles or Kilometers since the last oil change.
1. Does an oil change need to be performed? Has the customer exceeded the suggested oil change interval?
  ____ Yes - Before you proceed, request that the customer change the engine oil and the oil filter. After the engine oil and the oil filter have been changed, operate the engine until normal operating temperature has been reached. Run the engine up and down through the operating rpm range for 10 - 15 Minutes in order to purge any trapped air or debris from the injection actuation pressure system. If problem still exists proceed to Step 5.
  Note: Oil change is not covered as a warranty expense.
  ____ No - Proceed to Step 5.

Install 8T-0852 Pressure Gauge on the high pressure oil rail. Perform the step test and compare the pressures read with the pressure gauge to the pressures read by Cat ET.

Show/hide table

Table 3
Step	Manual Pressure gauge	Cat ET	Difference
1
2
3
4

Note: Depending on the interface which you are using, you may have either three or four steps.

Do the pressures measured in each step match within 1379 kPa (200 psi)?
____ Yes - The IAP Sensor is working properly. Proceed to Step 6.
____ No - The sensor is suspected. Replace the IAP Sensor and complete Step 5 one more time. If the problem still exists, install the original sensor and proceed to Step 6.

Perform the step test at low idle and at high idle.

Show/hide table

Table 4
Low Idle
Step	Actual injection pressure from Cat ET	Injection Pressure Percentage Output from Cat ET
1
2
3
4
High Idle
Step	Actual injection pressure from Cat ET	Injection Pressure Percentage Output from Cat ET
1
2
3
4

Does the percentage output exceed 65 percent?

____ Yes - Replace the IAPCV. Retest and record the data in Table 5. If the problem still exists install the original IAPCV and proceed to Step 7. The IAPCV is not the problem.

____ No - Call technical support for assistance.

Show/hide table

Table 5
Low Idle
Step	Actual injection pressure from Cat ET	Injection Pressure Percentage Output
1
2
3
4
High Idle
Step	Actual injection pressure from Cat ET	Injection Pressure Percentage Output
1
2
3
4

Disconnect the HEUI high pressure oil line from the cylinder head and install the 8T-0852 Pressure Gauge to the outlet of the high pressure line. Remove the IAPCV and install a 219-2368 Plug and 9X-1484 Seal Kit . Crank the engine and monitor the pressure on the gauge.
________ Observed Pressure
________ Observed RPM
1. Is the pressure above 27.5 MPa (4000 psi)?
  ____ Yes - The HEUI pump is working properly. Reinstall the original IAPCV and proceed to Step 10.
  ____ No - The HEUI pump is suspected. Proceed to Step 8.

Remove the HEUI pump and check the pump drive gear. Is the drive gear tight? Drive gear may move freely on the shaft if the gear is loose.
____ Yes - Replace the HEUI pump. If the problem persists contact technical support.
____ No - Proceed to Step 9.

Does the HEUI pump turn freely?
____ Yes - The drive gear has loosened. Tighten the drive gear to 110 ± 14 N·m (80 ± 10 lb ft). Checking the pressure with the procedure in Step 7 will indicate if the problem the problem is resolved. Contact technical support if problem still exists. ____No - The pump has failed. The pump failure has caused the drive gear to loosen. Replace the HEUI pump. Stop, problem solved do not proceed. If problem persists contact technical support.

Remove the valve cover and inspect the HEUI system for oil leaks. Look around the injector bores for any signs of oil leakage. Inspect the injector spill ports for excessive oil. All six injectors should spill the same amount of oil while the engine is being cranked. Are there leaks around the injector O-rings, or is there excessive oil coming from the injectors.
____ Yes - Replace the injector O-ring or the damaged injector.
____ No - Call technical support for assistance.