Parts for your 1990 Mitsubishi Pajero-Crank angle sensor

1990 Mitsubishi Pajero crank angle sensor — what it is and how to look after it

For 1990-model Mitsubishi Pajero petrol engines (notably the 3.0L V6 6G72 and many 2.6L 4G54 variants), a crank angle sensor is fitted inside the distributor and is used by the ignition and fuel systems to determine engine position and timing. Factory technical literature covers this clearly: the Mitsubishi Pajero/Montero Workshop Manual (late-1980s to early-1990s editions, Engine Electrical—Ignition) and the 6G72 Engine Service Manual describe the distributor’s internal signal generator as a crank/cam angle sensor. By contrast, the 2.5L 4D56 turbo-diesel of the same era uses a mechanically timed injection pump and typically does not employ a separate crank angle sensor, as noted in the Mitsubishi 4D56 Engine Manual and period workshop manuals from Gregory’s and Max Ellery.

Where it’s fitted (petrol models), the crank angle sensor’s job is to tell the ECU and ignition module exactly where the crank and cam are in their rotation so it can fire the spark and, on EFI models, deliver fuel at the right moment. Housed in the distributor, it reads an internal trigger wheel and sends a clean timing signal the engine absolutely relies on. If that signal goes walkabout, expect hard starting, random stalling, misfires, or a dead-no-start—often with a twitchy or dead tacho.

Servicing is mostly about prevention. Keep moisture and dust out of the distributor by ensuring the cap, rotor and seal are in good nick. Oil weeping from the distributor shaft seal can contaminate the sensor—fix the leak early. Check the harness plug and earths for corrosion or broken wires, especially if the vehicle has seen beach work or river crossings. On scheduled services, a quick visual of the cap and rotor and a wiggle test of the connector can save grief later.

If replacement is on the cards, many techs in Aus and NZ simply fit a complete quality replacement distributor rather than rebuilding the sensor assembly—it’s quicker and often more reliable long-term. If you do the job yourself: disconnect the battery, mark the distributor’s position relative to the housing and the housing to the engine so base timing goes back where it was, then swap like-for-like. After refit, follow the workshop procedure to set base timing with a timing light (using the specified timing check connector) and verify idle quality and hot restarts. A fresh cap, rotor and leads at the same time is smart money, especially on older looms. That way, the Pajero stays perky and ready for the next big trip.

• Technical sources referenced: Mitsubishi Pajero/Montero Workshop Manual (Engine Electrical—Ignition), Mitsubishi 6G72 Engine Service Manual (Ignition System), Mitsubishi 4G54 Engine Service data, Mitsubishi 4D56 Engine Manual, Gregory’s and Max Ellery’s Pajero workshop manuals covering late-1980s to early-1990s models.

Popular questions

Does a 1990 Pajero diesel have a crank angle sensor?
Most 1990 Pajero diesels with the 4D56 don’t use a separate crank angle sensor. They rely on a mechanically timed injection pump and often take engine speed from the alternator W terminal for the tacho. That’s why you won’t find a CAS on many diesel examples from this year.

Where is the crank angle sensor on a 1990 Pajero V6?
On the 3.0L V6 (6G72), it’s built into the distributor. The internal pickup and trigger wheel generate the engine position signal. So if you’re chasing CAS issues on a V6, you’ll be working at the distributor—cap off, rotor off, and into the guts.

What are the common signs the sensor is failing on petrol models?
Intermittent no-start when hot, random stalling at lights, misfires through the rev range, and a dropping or dead tacho are classic. If the ECU is fitted and capable of codes, you may also see a stored ignition/timing signal fault. Oil inside the distributor is another giveaway that the sensor is being contaminated.