Mitsubishi S4S-D — Inspection of Fuel Injection Timing (In-line Fuel Injection Pump)

Testing & diagnosis

For the Mitsubishi S4S-D, from the Mitsubishi service manual.

Applies to: Mitsubishi S4S-D, Mitsubishi S4S engine

Procedure

1. Bring No.1 piston to top dead center.
2. Remove delivery valve holder from No.1 plunger; remove delivery valve, spring and stopper; install delivery valve holder alone.
3. Install spare injection pipe to No.1 plunger with other end downward.
4. Position crankshaft about 60 deg before TDC of No.1 piston on compression stroke.
5. Feed fuel by priming pump and slowly turn crankshaft allowing fuel to flow from the pipe.
6. Slowly turn further when flow is about to stop; stop when flow stops.
7. Check the line on the crankshaft pulley and pointer indicate the fuel injection timing.

Source: Mitsubishi 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.

More Mitsubishi repair guides →