1 E3 - Preliminary Check

Before using this diagnostic chart, ensure that:

1.   There are no problems with transmission

2.   There are no engine mechanical problems

3.   There is not an excessive load on the  engine

4.   There is no unbalanced ballast

5.   The air and fuel filters are not restricted or  plugged

6.   Fuel quality is OK

Problem not found:

GO TO  2

Problem found: Repair and retest

– – –1/1

2 Intermittent Fault Test

Using the DST, monitor DTCs on the active code display  parameter.

NOTE: Look for DTCs that indicate a fuel derate is or has been in   effect.

No DTCs present:

GO TO  3

DTCs present:

Go to appropriate diagnostic procedure.

– – –1/1

3 Exhaust Emission Check

1.   Operate engine at full load rated speed

2.   Under these conditions, determine type of exhaust emitted.

Small amount or no exhaust smoke:

GO TO  4

Heavy white exhaust smoke:

See E4 - ENGINE EMITS EXCESSIVE WHITE EXHAUST SMOKE

diagnostic procedure later in this Group.

Heavy black or gray exhaust smoke:

See E5 - ENGINE EMITS EXCESSIVE BLACK or GRAY EXHAUST

SMOKE diagnostic procedure later in this Group.

– – –1/1

4 Torque Curve Selection Check

NOTE: 6750/6850 Self-Propelled Forage Harvester applications only use one torque curve; therefore, this check is not required.

The ECU on engines has the ability to operate on multiple torque curves. To check   that the engine is operating on the correct torque curve under the operating conditions where there is a low power complaint:

1.   Recreate the conditions of the low power  complaint.

2.   Using the DST, read the Torque Curve  Parameter

3.   Compare the torque curve number with the one shown in TORQUE CURVE SELECTION in Section 06, Group 210.

The torque curve number displayed IS correct for the operating conditions of the low power complaint:

GO TO  5

The torque curve number displayed IS NOT correct for the operating conditions of the low power complaint:

Refer to machine manual to determine components that if faulty could prevent the correct torque curve from being selected

OR

Faulty torque curve select wiring

– – –1/1

5 Governor Droop Mode Selection Check

1.   Operate engine and attempt to recreate the low power  condition.

2.   Using the DST, read the Desired Speed Governor parameter and the Maximum Speed Governor parameter

3.   Compare governor selection to the appropriate chart governor mode chart. See GOVERNOR DROOP MODE SELECTION in Section 06, Group  210.

Governor selection is correct:

GO TO  6

Governor selection is incorrect:

Refer to machine manual to determine components that if faulty could prevent the correct governor from being selected.

OR

Faulty governor select wiring.

– – –1/1

6 Compression and Misfire Test

1.   Using the DST, perform the Compression Test. For instructions, see DST ENGINE TEST INSTRUCTIONS - COMPRESSION TEST in Group 160.

2.   Make note of the results.

3.   Using the DST, perform the Engine Misfire Test. For Instructions, see DST ENGINE TEST INSTRUCTIONS - CYLINDER MISFIRE TEST in Group  160.

4.   Make note of the results.

All cylinders scored within 10% of each other on both tests: GO TO  7

One or more cylinders scored 10% or more lower than the rest on either test: Go to E2 - ENGINE MISFIRES/RUNS

IRREGULARLY in this Group.

– – –1/1

7   Throttle Test

1.   Operate engine at full load rated speed

2.   At these operating conditions, read the Percent Throttle data parameter in the  DST.

97% or above:

GO TO  8

Below 97%:

Refer to machine manual and perform the throttle calibration procedure and retest.

– – –1/1

9 Fuel Supply System Check

Check the fuel supply system.

·   For Dual Rail fuel systems, see F1 - DUAL RAIL FUEL SUPPLY SYSTEM CHECK in this Group.

·   For Single Rail fuel systems, see F4 - SINGLE RAIL FUEL SUPPLY SYSTEM CHECK in this Group.

Fuel supply system is OK:

Engine appears to be delivering full power. Check for vehicle problems that could cause an excessive load on the engine.

Fuel supply system problem found:

Repair fuel supply system problem and retest.

– – –1/1

10 Checking Potential Causes of Low Boost Pressure

Check for the following that can cause reduced boost  pressure:

·   Restricted air cleaner

·   Intake air leak

·   Exhaust air leak

·   Restriction in exhaust

·   Faulty turbocharger. See TURBOCHARGER SEVEN-STEP INSPECTION in Section 02, Group 080, of CTM100.

None of the above problems found: GO TO 11

Problem found:

Repair and retest.

– – –1/1

11 Fuel Supply System Check

Check the fuel supply system.

·   For Dual Rail fuel systems, see F1 - DUAL RAIL FUEL SUPPLY SYSTEM CHECK in this Group.

·   For Single Rail fuel systems, see F4 - SINGLE RAIL FUEL SUPPLY SYSTEM CHECK in this Group.

Fuel supply system is OK:

GO TO 12

Fuel supply system problem found:

Repair fuel supply system problem and retest

– – –1/1

12 EUI and Valve Adjustment Test

1.   Check EUI pre-load adjustment and check valve adjustment. See CHECK AND ADJUST VALVE ASSEMBLY CLEARANCES AND INJECTOR PRELOAD in Section 02, Group 020 of CTM100.

2.   Ensure there are no engine mechanical problems

3.   Ensure there isn’t something drawing excessive engine power

4.   If none of above problems are found, the most likely cause of low power is damaged spill valves in the EUIs. Replace and  retest.

– – –1/1