Detroit Diesel Troubleshooting Diagrams

To determine if a faulty fuel injector is causing the cylinder to misfire, perform the following steps: ‪

1. Install DDL adaptor to the data cable and plug the adaptor into the DDL connector in the vehicle; refer to OEM guidelines.
2. Start and run the engine at no-load.
3. From the DDEC III/IV Select Menu, scroll to select ENGINE and press the ENTER key.
4. Scroll to FUEL INJECTOR INFO (CUTOUT) and press the ENTER key.
5. Scroll to select NEW TEST and press the ENTER key.
6. Scroll to select RPM SETTING FOR CCO TEST NORMAL and scroll to select 1000 and press the ENTER key.
7. Scroll to select AUTO and press the ENTER key. Wait for END OF TEST.

Note: If an injector cannot be cutout, an ERROR message will appear. Press FUNC to exit the cylinder cutout function, press the FUNC key.

8. Scroll the list to review the results of the cylinder cutout test. To find suspect injectors, look for a cylinder with a value that is within 0.2 ° of the NO CUTOUT PULSE WIDTH, by comparing the CUTOUT PULSE WIDTH values to the NO CUTOUT PULSE WIDTH values.

If any CUTOUT PULSE WIDTH values are within 0.2 ° of the NO CUTOUT PULSE WIDTH, shut down the engine;
If any CUTOUT PULSE WIDTH values are not within 0.2 ° of the NO CUTOUT PULSE WIDTH, shut down the engine

To determine if a faulty exhaust system is causing excessive exhaust smoke, perform the following:

1. Drill an 11/32 in. hole in the exhaust pipe, 5 to 12 in. (127 – 305 mm) from the turbocharger exhaust outlet.

Note: The tapped hole must be in a comparatively straight area of the turbocharger exhaust outlet.

2. Tap the hole to accommodate an 1/8 in. pipe plug.
3. Connect a manometer to the tapped hole.
4. Start and run the engine.
5. Run the engine at idle with a no-load for approximately 5 minutes, allowing the engine coolant to reach normal operating range.
6. Run the engine speed to full load.

If the exhaust back pressure at full load is less than 3.0 in. Hg (10.1 kPa), check the fuel injectors.
If the exhaust back pressure at full load is 3.0 in. Hg (10.1 kPa) or greater

To determine if a charge air cooler is causing excessive exhaust smoke, perform the following: ‪

1. Attach a WK93 air-to-air charge air cooler test kit; refer to OEM guidelines.
2. Disconnect the air inlet hose from the outlet side of the turbocharger compressor housing;
3. Attach the air-to-air cooler test kit adaptor plug to fit into the hose at the compressor connector; refer to OEM guidelines.
4. Attach an air pressure hose to the air chuck at the regulator and gradually pressurize the air inlet system to a pressure of 25 · lb · in. 2 (177 kPa).
5. Apply a water and soap solution to each hose connection, across the face of the charge air cooler.
6. Apply a water and soap solution to the air intake manifold and cylinder head mating surface area.
7. Visually inspect all joints for air leaks and all charge air cooler welded surfaces for stress cracks

If air leaks are present around the joints, replace the charge air cooler;
If any leaks are present around the air intake manifold, repair the air intake manifold;
If no leaks are present, check for faulty exhaust system;

To determine if a defective air compressor is causing excessive crankcase pressure, perform the following: ‪

1. Perform a crankcase pressure test and record the test results.
2. Disconnect the air outlet line from the air compressor;

3. Repeat step and record the test results.
4. Compare the results of test one with test two.

If the engine crankcase pressure remained the same, check the turbocharger;
If the engine crankcase pressure decreased, repair the air compressor;

To determine if an obstructed or damaged breather is causing excessive crankcase pressure, perform the following: ‪

Perform a crankcase pressure test.

If the engine crankcase pressure is less than 3 in. H 2 O (0.75 kPa), check the air compressor.
If the engine crankcase pressure is greater than 3 in. H 2 O (0.75 kPa), replace wire mesh element.

Rocker Cover Breather Resolution

Perform the following steps to replace wire mesh element replacement: ‪

1. Remove the valve rocker cover(s);
2. Remove the wire mesh form the rocker cover;
3. Install a new wire mesh element to the rocker cover;
4. Install the rocker cover to the engine;
5. Verify replacement of wire mesh element;

A loss of cylinder pressure can cause increased oil consumption. The detection and elimination of cylinder pressure losses is vital to engine life and efficient operation. To assist the mechanic in effectively measuring the loss of cylinder pressure, and locating the source of abnormal leaks in individual cylinders, the following test procedure has been developed.

1. Move the vehicle requiring test to the chassis dynamometer; refer to OEM guidelines.
2. Disconnect air compressor.
3. Start the engine.
4. Run the engine and bring the engine coolant temperature to normal operating range.
5. Run vehicle to full load and rated speed.
6. Attach a manometer calibrated to read in inches of water, to the oil dipstick opening. Measure and record the crankcase pressure.
7. Shut down engine.
8. Remove the vehicle from the chassis dynamometer.
9. Review the crankcase pressure test results.
If the crankcase pressure exceeds 0.75 kPa (3 in. H 2 O), repair worn or damaged valve(s) or cylinder kit; r
If the crankcase pressure was less than or equal to 0.75 kPa (3 in. H 2 O), perform cylinder compression test.
10. Compare the cylinder compression test results to specifications.
If the cylinder compression is below specifications, repair worn or damaged valve(s) or cylinder kit;
If the cylinder compression is within specification, call Detroit Diesel Technical Service Group

To determine if a defective turbocharger is causing excessive oil consumption, perform the following: ‪

1. Remove the turbocharger drain line connected to the crankcase and place the drain line into a suitable container.
2. Perform a crankcase pressure test.

If the engine crankcase pressure is less than 0.75 kPa (3 in. H 2 O), replace the turbocharger;
If the engine crankcase pressure is 0.75 kPa (3 in. H 2 O) or more, check for worn or damaged valve and cylinder kit;

To determine if a defective air compressor is causing excessive oil consumption, perform the following: ‪

1. Perform a crankcase pressure test and record the test results.
2. Disconnect the air outlet line from the air compressor;

3. Repeat step and record the test results.
4. Compare the results of test one with test two.

If the engine crankcase pressure remained the same, check the turbocharger;
If the engine crankcase pressure decreased, replace the air compressor

To determine if a leaking oil cooler core is causing excessive oil consumption, perform the following: ‪

1. Check for oil in the engine coolant or radiator.
If oil is present in either the engine coolant or radiator;
If no oil is present in either the engine coolant or radiator, check for a defective air compressor;
2. Remove the oil cooler core and housing;
3. Clean both the oil side and water side of oil cooler core;
4. Perform an oil cooler core pressure test;
5. Visually check to see if air bubbles are rising to the surface of the water within the container.
If air bubbles are present
If no air bubbles are present, complete a lube oil consumption report, call the Detroit Diesel Technical Service Group for a form.

To determine if oil leaks are causing excessive oil consumption, perform the following:

1. Start and run the engine to operating temperature 88 ° C (190 ° F).
2. Check for leaks at oil lines, connections, mating joints, seals, and gaskets

If no oil leaks are found, shut down the engine and check for a leaking oil cooler core;
If oil leaks are found, shut down the engine;

Engine Oil Leak Repair

Perform the following steps, as necessary, to resolve engine oil leaks: ‪

1. Repair or replace components leaking oil;
2. Verify repairs made to correct oil leaks;