Mitsubishi S12A2 — Change fuel injection nozzle tip
Repair & overhaul
For the Mitsubishi S12A2, from the Mitsubishi owner's manual.
Applies to: Mitsubishi S12A2, Mitsubishi S12A2 engine
Before you start
- Do not give shock to the end of the nozzle tip.
- Do not use Moly Disulfide.
- Do not allow fuel injected from a nozzle to contact the skin or body when testing.
Procedure
- Remove the rocker cover, remove the clamp and the fuel injection pipe and leak-off pipe.
- Remove the nozzle gland nut and pull out the nozzle using nozzle remover 36291-00900.
- Secure the nozzle in a vice, remove the cap nut and loosen the adjusting screw.
- Remove the retaining nut and take the nozzle tip off.
- Install the new nozzle tip according to the pin on the nozzle.
- Tighten the retaining nut to 59 to 78 N-m (6±8 kgf-m) [43±58 lbf-ft] after applying oil to the nut.
- Adjust fuel injection start pressure and check spray conditions.
- Reinstall nozzle with a new gasket and tighten the gland nut to 78 N-m.
- Install the fuel injection pipe and leak-off pipe with sealing washers; tighten eyebolt to 15 to 20 N-m.
- Run the engine at 600 rpm with rocker cover removed and check for fuel leakage.
Tools required
- Nozzle remover 36291-00900 Amazon
- Vice Amazon
- Screw driver Amazon
- Nozzle tester Amazon
- Torque wrench Amazon
Tool links are Amazon searches (affiliate links); manufacturer special tools may only be available from a dealer.
Specs & values
- Retaining nut torque 59 to 78 N-m (6±8 kgf-m) [43±58 lbf-ft]
- Cap nut torque 44±5 N-m (4.5±0.5 kgf-m) [32.5±3.6 lbf-ft]
- Nozzle gland nut torque 78 N-m (8 kgf-m) [58 lbf-ft]
- Eyebolt torque 15 to 20 N-m (1.5 to 2 kgf-m) [10.8 to 14.5 lbf-ft]
- Fuel injection start pressure 21.57 MPa {220 kgf/cm2} [3,130 psi]
Full service-parts list: Mitsubishi S12A2 →
Source: Mitsubishi owner's 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.