B5.9G, B5.9LPG – Troubleshooting and Repair Manual – Engine Difficult to Start (Cranking Time Exceeds 3 Seconds)

Electronic fault codes active or high counts of inactive fault codes

Refer to Section TF in the Troubleshooting and Repair Manual, Fuel Systems and Electronics, B5.9G, C8.3G, L10G-III, Bulletin 3666118, for fault code troubleshooting.

Electronic control module (ECM) calibration is malfunctioning

Verify the ECM calibration is correct. Check the calibration revision history for applicable fixes to the calibration stored in the ECM. Refer to the calibration history spreadsheet Click here to see ecm_calibration_rev_history.xls

on QuickServe® Online or the INCAL™ CD-ROM. Compare the calibration stored in the ECM with the engine rating and Control Parts List (CPL), Bulletin 4021326 or 4021327. If necessary, recalibrate the ECM. Refer to the appropriate electronic service tool manual and Procedure 019-032 in the Troubleshooting and Repair Manual, Fuel Systems and Electronics, B5.9G, C8.3G, L10G-III, Bulletin 3666118.

Battery voltage is low

Check the electrolyte level (not maintenance-free batteries) in each cell. Add distilled water if necessary. Check the “eye” on the maintenance-free batteries; replace batteries if necessary. Refer to the OEM service manual.

Battery voltage supply to the electronic control module (ECM) is low, interrupted, or open

Check the battery connections, the fuses, and the unswitched battery supply circuit. Refer to Procedure 013-009 and Procedures 019-198 and 019-087 in the Troubleshooting and Repair Manual, Fuel Systems and Electronics, B5.9G, C8.3G, L10G-III, Bulletin 3666118.

Starting procedure is not correct

Verify the correct starting procedure. Refer to the Operation and Maintenance Manual, B5.9G, B5.9LPG, B Gas Plus, and B LPG Plus Engines, Bulletin 3666112, and the OEM service manual to review the engine and vehicle starting procedures.

Engine cranking speed is too slow

Check the engine cranking speed with a handheld tachometer or electronic service tool. If the cranking speed is slower than 150 rpm, refer to the Engine Will Not Crank or Cranks Slowly symptom tree.

Fuel leak

Check the fuel lines, fuel connections, and fuel filters for leaks using the combustible gas detector service tool. Refer to Procedures 005-003, 005-047, and 005-052.

Low or no fuel pressure at the mixer (secondary pressure)

Use an electronic service tool to measure the fuel pressure after the gas mass flow sensor and before the mixer. Refer to Procedure 005-047.

Low or no fuel pressure at the fuel filter (primary pressure)

Use an electronic service tool to measure the fuel pressure at the fuel filter. Refer to Procedure 005-061.

Engine position sensor (EPS) is not installed correctly

Check the engine position sensor for correct installation. Refer to Procedure 019-038 in the Troubleshooting and Repair Manual, Fuel Systems and Electronics, B5.9G, C8.3G, L10G-III, Bulletin 3666118.

Engine position sensor (EPS) or circuit is malfunctioning

Check the engine position sensor and circuit. Refer to Procedures 019-038 and 019-039 in the Troubleshooting and Repair Manual, Fuel Systems and Electronics, B5.9G, C8.3G, L10G-III, Bulletin 3666118.

Coil wire malfunctioning

Remove wire from engine and use a digital multimeter to measure resistance across the wire. Refer to Procedure 013-012.

Ignition coil malfunctioning

Check the ignition coil. Refer to Procedure 013-012.

Spark plug(s) damaged or incorrect gap

Inspect plug(s). Refer to Procedure 013-016.

Ignition system harness connector pins bent or damaged

Inspect harness. Refer to Procedure 019-196 in the Troubleshooting and Repair Manual, Fuel Systems and Electronics, B5.9G, C8.3G, L10G-III, Bulletin 3666118.

Fuel control valve is malfunctioning

Check the fuel control valve for sticking or hysteresis. Refer to Procedure 019-102 in the Troubleshooting and Repair Manual, Fuel Systems and Electronics, B5.9G, C8.3G, L10G-III, Bulletin 3666118.

Incorrect fuel control valve installed

Verify the fuel control valve part number.

Auxiliary drive units are engaged

Disconnect the auxiliary drive units.

Overhead adjustments are not correct

Adjust the overhead settings. Refer to Procedure 003-004.

Crankshaft rotation is impaired

Check the crankshaft for ease of rotation. Refer to Procedure 001-016.