Parts for your 1987 Mitsubishi Pajero-Map sensor

1987 Mitsubishi Pajero MAP sensor — is it used on these old legends?

Short answer: a MAP sensor isn’t a thing on an Aussie/Kiwi–market 1987 Mitsubishi Pajero. Based on factory and aftermarket repair literature for the first‑gen L040 series, the petrol models of the era ran a carburettor (G54B 2.6) and the diesels used a mechanically governed rotary (VE‑type) pump on the 4D55/4D56. There’s no engine ECU, so there’s no electronic manifold absolute pressure (MAP) sensor to feed data to. Later EFI petrols (and later‑gen Pajeros) use electronic management, typically with an airflow meter on many Mitsubishis of the time rather than a MAP, but that’s not the 1987 setup.

Why it’s not used: on the carburetted petrol, manifold vacuum is simply a physical signal inside the carb to pull fuel through the jets — a MAP sensor would be redundant without an ECU. On the mechanical turbo‑diesel, boost pressure is sent via a small hose to an aneroid (boost compensator) on the injection pump, which is a purely mechanical device that enriches fuel with boost. That’s often mistaken for a “MAP sensor line”, but it isn’t electronic and there’s no sensor to replace.

If someone’s hunting for a Pajero “MAP sensor” because it’s running rough, they’re usually chasing the wrong part. The fixes live elsewhere:

• Petrol G54B: check for vacuum leaks (brittle hoses, intake gasket), carb cleanliness and float level, ignition timing and advance, plugs/leads/cap/rotor, and fuel filter.
• Diesel 4D56/4D55: inspect the boost hose to the aneroid for splits, air and fuel filters, pump timing, valve clearances, and intercooler/charge piping if fitted.

Technical sources referenced for this model-year callout include: Mitsubishi Pajero (L040) factory workshop manual groups covering Fuel (carburettor) and Diesel Fuel (VE‑type pump), period wiring diagrams showing no ECU/MAP circuit, the Mitsubishi ASA/CAPS parts catalogue for L040/L141 listing no MAP sensor for 1987 AU/NZ specifications, and Haynes/Gregory’s repair manuals describing carburetted petrol and mechanically injected diesel systems on first‑gen Pajero. These consistently indicate no electronic MAP sensor on 1987 models sold here.

• Does a 1987 Mitsubishi Pajero have a MAP sensor?
  No. Petrol models are carburetted and diesels use a mechanical injection pump, so there’s no ECU and no MAP sensor. Some later EFI Pajeros use electronic management, but not the ’87 AU/NZ vehicles.
• I found a small hose on my 4D56T pump — is that a MAP sensor line?
  That hose feeds boost to the aneroid (boost compensator) on the diesel pump. It’s mechanical, not electronic. If the hose is split or off, you’ll get low power, smoke, or weird fuelling under boost — replace the hose and clamps and you’re sorted.
• My 1987 Pajero runs rough — what should I check instead of a MAP sensor?
  Petrol: vacuum leaks, carb service, ignition timing/advance, and basic tune items. Diesel: air and fuel filters, boost hose to the aneroid, pump timing, and valve clearances. These fix most dramas on first‑gen trucks.