John Deere — Adjust Electronic Unit Injector Preload
Adjustments
From a John Deere service manual — check it applies to your exact model before use.
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Before you start
- Timing pin MUST BE installed in slot of camshaft first, then in crankshaft slot.
- DO NOT insert timing pin full depth into crankshaft timing hole when rotating flywheel until double slot on camshaft timing lobe is at approximately 11 o'clock.
Procedure
- Remove plug from cylinder block and install JDG820 Flywheel Turning Tool.
- Rotate flywheel in running direction until JDG971 Timing Pin engages single timing slot in camshaft (TDC No. 1 compression).
- Remove threaded plug from crankshaft timing hole below oil cooler and filter housing assembly.
- Rock flywheel back and forth until second JDG971 Timing Pin enters crankshaft slot.
- Loosen lock nut and loosen cylinders Nos. 3, 5, 6 injector rocker arm adjusting screws to relieve tension.
- Slowly tighten adjusting screw until rocker arm roller contacts camshaft lobe at 0.0 clearance.
- Tighten adjusting screw an additional 1/2 turn (180°) to preload injector.
- Tighten adjusting screw lock nut to specification while holding adjusting screw stationary.
- Remove both timing pins, rotate crankshaft one full revolution (360°) and pin crankshaft only (No. 6 TDC).
- Set injector preload on cylinders Nos. 1, 2, and 4.
- Install plug in timing pin hole in block and tighten to specification.
Tools required
Tool links are Amazon searches (affiliate links); manufacturer special tools may only be available from a dealer.
Specs & values
- Electronic Unit Injector Adjusting Screw Lock Nut—Torque 65 N·m (48 lb-ft)
- Timing Pin Plug in Cylinder Block—Torque 33 N·m (24 lb-ft)
Source: John Deere service manual. Steps and values are as documented; always cross-check against the official manual and any later revisions for your exact serial number before servicing.