0504-19 Service Bulletin/Repair Instructions

05 04-19
1
05 04-19
SUBJECT
DATE
Low Power or Rough Running
May 2019
Additions, Revisions, or Updates

Publication Number / Title
DDC-SVC-MAN-0010
Platform
Section Title
Change
EPA07

MBE4000
Low Power or Rough

Running
Rename section to "Low Power or Rough Running". Remove the

current sections 14.8 and 14.10. Update information in this section.

Delete all of Section 13.
All information subject to change without notice.
05 04-19
Copyright © 2019 DETROIT DIESEL CORPORATION
3
EPA07 MBE 4000 DDEC VI TROUBLESHOOTING GUIDE
13.1 LOW POWER/ROUGH RUNNING

Check as follows:

1. 1. Are there any active fault codes or starting difficulties?

[a]
Yes; perform the troubleshooting for the active code or starting difficulty first;

refer to section 5
[b]
No; go to step 2.
2. Was the oil filter recently removed?

[a]
Yes; remove oil filter and inspect the bypass valve. Go to step 3.
[b]
No; go to step 4.
3. Is the bypass valve damaged or unseated?

[a]
Yes; repair as necessary.
[b]
No; go to step 4.
4. Start the engine and observe the fuel pressure using a mechanical gauge. Compare fuel

pressures to the chart below:

Estimated Fuel Pressures

RPM
EPA 07 MBE 4000
600
448 to 482 kPa (65 to 70 psi)
1800
620 to 655 kPa (90 to 95 psi)
5. Are the fuel pressures within range as per the chart?

[a]
Yes; go to step 10.
[b]
No; go to step 6.
6. Bypass the chassis fuel system. Are fuel pressures within range?

[a]
Yes; inspect OEM fuel system for potential restrictions or leaks.
[b]
No; go to step 7.
7. Replace the fuel filters (only use correct MBE brand fuel filters). Are fuel pressures

within range?

[a]
Yes; verify repairs.
[b]
No; go to step 8.
8. Replace the overflow valve. Refer to section 4.3 of the EPA07 MBE 4000 workshop

manual. Are fuel pressures within range?

[a]
Yes; verify repairs.
All information subject to change without notice.
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Copyright © 2007 DETROIT DIESEL CORPORATION
13-3
13.1
LOW POWER/ROUGH RUNNING
[b]
No; go to step 9.
9. Check for aerated fuel. Refer to section 13.2. Is fuel aerated?

[a]
Yes; refer to aerated fuel resolution. Refer to section 13.2.1
[b]
No; replace low pressure fuel pump.
10. Using Diagnostic Link®, perform a Relative Compression test. The test measures

relative compression of each cylinder with the “best” one shown as 100% and the others

displayed as a percentage of the best cylinder. Look for cylinders that are more than

10% lower than the highest cylinder. This will be the suspected bad cylinder. Does the

relative compression test pass?

[a]
Yes; go to step 12.
[b]
No; perform mechanical compression test (refer to section 2.2 ) and go to step 11.
11. Does the mechanical compression test pass?

[a]
Yes; go to step 12.
[b]
No; find the cause of the low compression and repair as necessary
12. Using Diagnostic Link perform an Idle Speed Balance (ISB) test. Does any cylinder fail

the ISB test?

[a]
Yes; inspect high pressure fuel system on the cylinder that failed the test and repair

as necessary
[b]
No; go to step 13.
13. Remove the air filter element from the air cleaner container; refer to OEM guidelines. Is

the air filter damaged or clogged?

[a]
Yes; replace air filter element. Verify repairs.
[b]
No; go to step 14.
14. Check for restricted or cracked CAC; refer to section 13.7. Was damage found?

[a]
Yes; repair as necessary; refer to section 13.7.
[b]
No; go to step 15.
15. Check for leaking intake manifold gasket; refer to section 13.8. Was damage found?

[a]
Yes; repair as necessary. Refer to section 13.8.
[b]
No; go to step 16.
16. Unplug the fuel temp sensor and test drive the unit. Does the unit still have low power?

[a]
Yes; go to step 17
[b]
No; replace the fuel temp sensor and verify repairs.
17. Unplug the inlet air temperature sensor and test drive the unit. Does the unit still have

low power?

[a]
Yes; go to step 18.
All information subject to change without notice.
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EPA07 MBE 4000 DDEC VI TROUBLESHOOTING GUIDE
[b]
No; replace the inlet air temperature sensor and verify repairs
18. Verify proper turbo operation and inspect for damage. Refer to letter 18SP670 for turbo

waste gate operation. Is the turbo operating correctly?

[a]
No; repair as necessary
[b]
Yes; replace fuel nozzles.
All information subject to change without notice.
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Copyright © 2007 DETROIT DIESEL CORPORATION
13-5
13.2
AERATED FUEL
13.2 AERATED FUEL

To determine if aerated fuel is causing lack of power, perform the following steps:

1. Test for aerated fuel.

2. Disconnect the fuel line return hose from the fitting located at the fuel tank; refer to OEM

guidelines.

3. Place the open end of the fuel line into a suitable container.
PERSONAL INJURY

Diesel engine exhaust and some of its constituents are

known to the State of California to cause cancer, birth

defects, and other reproductive harm.

□ Always start and operate an engine in a well ventilated

area.

□ If operating an engine in an enclosed area, vent the

exhaust to the outside.

□ Do not modify or tamper with the exhaust system or

emission control system.
PERSONAL INJURY

To avoid injury before starting and running the engine,

ensure the vehicle is parked on a level surface, parking

brake is set, and the wheels are blocked.
PERSONAL INJURY

To avoid injury from inhaling engine exhaust, always

operate the engine in a well-ventilated area.

Engine

exhaust is toxic.

4. Start and run the engine.

5. Operate the engine at 1000 rpm.

6. Visually check to see if air bubbles are rising to the surface of the fuel that collects within

the container.

[a]
If air bubbles are not present, shut down the engine, return, and continue with the

initial diagnostics that directed you to Aerated Fuel.
All information subject to change without notice.
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Copyright © 2007 DETROIT DIESEL CORPORATION
EPA07 MBE 4000 DDEC VI TROUBLESHOOTING GUIDE
[b]
13.2.1
If air bubbles are present, shut down the engine; refer to section 13.2.1.
Aerated Fuel Resolution
Perform the following steps to resolve aerated fuel condition:

1. Tighten all fuel line connections between fuel tank and fuel pump; refer to OEM

guidelines.

2. Visually inspect all fuel lines between fuel tank and fuel pump for leaks.

3. Repair damaged components as required; refer to OEM guidelines.

4. Verify aerated fuel resolution; refer to section 13.2.1.1.
All information subject to change without notice.
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Copyright © 2007 DETROIT DIESEL CORPORATION
13-7
13.2
AERATED FUEL
13.2.1.1
Test the Engine with Aerated Fuel Resolution
Perform the following steps to determine if aerated fuel resolution has resolved lack of power

condition:
PERSONAL INJURY

Diesel engine exhaust and some of its constituents are

known to the State of California to cause cancer, birth

defects, and other reproductive harm.

□ Always start and operate an engine in a well ventilated

area.

□ If operating an engine in an enclosed area, vent the

exhaust to the outside.

□ Do not modify or tamper with the exhaust system or

emission control system.
PERSONAL INJURY

To avoid injury before starting and running the engine,

ensure the vehicle is parked on a level surface, parking

brake is set, and the wheels are blocked.
PERSONAL INJURY

To avoid injury from inhaling engine exhaust, always

operate the engine in a well-ventilated area.

Engine

exhaust is toxic.

1. Start and run the engine.

2. Run the engine at idle with a no-load condition for approximately five minutes, allowing

the engine coolant to reach normal operating range.

3. Test drive the vehicle to ensure lack of power has been resolved.

[a]
If no lack of power occurred during the test drive, no further troubleshooting is

required. Shut down the engine.
[b]
No; shut down the engine, return, and continue with the initial diagnostics that

directed you to Aerated Fuel.
All information subject to change without notice.
13-8
6SE568
Copyright © 2007 DETROIT DIESEL CORPORATION
EPA07 MBE 4000 DDEC VI TROUBLESHOOTING GUIDE
13.3 HIGH FUEL PRESSURE

To determine if high fuel pressure is causing a lack of power, perform the following steps:

1. Disconnect the electrical connector from the fuel temperature sensor.

2. Remove the fuel temperature sensor and washer. See Figure 13-1.
1. Fuel Temperature Sensor
Figure 13-1
Disconnecting the Sensor
3. Install the adaptor and banjo fitting, part of kit (J-46377), and high pressure line.

See Figure 13-2.
1. Adaptor form Kit J-46377
2. Banjo Fitting
3. Electronic Unit Pump
4. High Pressure Line J-46372
Figure 13-2
Connecting the Adaptor
All information subject to change without notice.
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13.3
HIGH FUEL PRESSURE
4. Attach a calibrated gauge (J-46378) capable of reading 0-100 psi, to the high-pressure fuel

line (J-46372), leading to the tee-fitting. See Figure 13-2.
PERSONAL INJURY

Diesel engine exhaust and some of its constituents are

known to the State of California to cause cancer, birth

defects, and other reproductive harm.

□ Always start and operate an engine in a well ventilated

area.

□ If operating an engine in an enclosed area, vent the

exhaust to the outside.

□ Do not modify or tamper with the exhaust system or

emission control system.
PERSONAL INJURY

To avoid injury before starting and running the engine,

ensure the vehicle is parked on a level surface, parking

brake is set, and the wheels are blocked.
PERSONAL INJURY

To avoid injury from inhaling engine exhaust, always

operate the engine in a well-ventilated area.

Engine

exhaust is toxic.

5. Start and run the engine to the speedsRefer to section 11.8.2 and record the fuel pressure.
Table 13-1
Engine Speed, rpm
Fuel Pressure, kPa (psi)
600-650
430 (62)
2500
400-650 (58-94)
Fuel Pressure at Various Speeds
6. Shut down the engine.

7. Remove the adaptor, banjo fitting, high pressure line, and high pressure gauge.

8. Reinstall the fuel temperature sensor and new washer. Torque the sensor to 30 N·m (22

lb·ft).
All information subject to change without notice.
13-10
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Copyright © 2007 DETROIT DIESEL CORPORATION
EPA07 MBE 4000 DDEC VI TROUBLESHOOTING GUIDE
9. Connect the electrical connector to the fuel temperature sensor.

10. Analyze the measure fuel pressure readings.

[a]
If the fuel pressure is within specifications listed in Table 13-1, check for high fuel

temperature return; refer to section 13.5.
[b]
If the fuel pressure is greater than specifications listed in Table 13-1, Refer to section

13.4.1.
All information subject to change without notice.
6SE568
Copyright © 2007 DETROIT DIESEL CORPORATION
13-11
13.4
FAULTY OVERFLOW VALVE
13.4 FAULTY OVERFLOW VALVE

To determine if a faulty overflow valve is causing a lack of power, perform the following steps:

1. Run Fuel system Test #1: Downstream Pressure Test. Refer to section 4.3.

2. If Test #1 indicates faulty overflow valve, proceed to step 3.

3. Run fuel system Test #3: Flow Test – At Fuel Filter. Refer to section 4.5.

4. If the overflow valve is found to be faulty, replace the overflow valve. Refer to section

13.4.1.
13.4.1
Overflow Valve Replacement
Perform the following steps to replace the overflow valve.

1. Remove the overflow valve from the fuel return line.

2. Install a new overflow valve. Tighten the valve to 48-52 N·m (35-38 lb·ft). See Figure

13-3.
1. Unit Pump
4. Overflow Valve
2. Bypass to Fuel Return Port
5. Constant Ventilation (overflow)
3. Fuel Injector
Figure 13-3
Overflow Valve Location
3. Verify overflow valve replacement; refer to section 13.4.1.1.
All information subject to change without notice.
13-12
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Copyright © 2007 DETROIT DIESEL CORPORATION
EPA07 MBE 4000 DDEC VI TROUBLESHOOTING GUIDE
13.4.1.1
Test the Engine with Replaced Overflow Valve

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