GM 6.5L V8 – Electrical Systems – Related Diagnosis/Service Procedures – Cranking Speed Check

1. Remove the B+ wire from the fuel shut-off solenoid wire on the injection pump.
2. Remove the glow plug for one cylinder.
3. Install compression gauge adapter J 26999-10 into the glow plug hole of the cylinder.
4. Connect compression gauge J 26999-12 to the adapter, and press the gauge pressure relief valve.
5. Crank the engine in the following manner:
• Allow initial cranking for three seconds.
• Count the number of “ puffs” that occur in the next 10 seconds of cranking.
• Stop cranking.
6. Calculate the cranking speed by multiplying the number of “ puffs” by 12.
Example: 10 “ puffs” times 12 is 120 cranking rpm.
7. Remove the gauge and install the glow plug (tighten to 11 to 16 N-m [8 to 12 Ib-ft] torque).
8. Connect the B+ wire for the injection pump fuel shut-off solenoid.
9. Check the engine operation and charge the batteries.

Note: Minimum cranking speed is 100 rpm with a cold engine and 180 rpm with a warm or hot engine. Actual cranking speed needed will vary depending on the condition of the engine (compression) and nozzles.

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