Parts for your 1991 Mitsubishi Pajero-Fuel injectors

1991 Mitsubishi Pajero Fuel Injectors

Technical references including the Mitsubishi Pajero/Montero factory workshop manual (1990–1992, Fuel – Multi-Point Injection section), Mitsubishi ASA Electronic Parts Catalogue listings for 1991 Pajero engines, and Haynes/Gregory’s Pajero service manuals confirm that many 1991 Pajero variants were built with fuel injectors. Petrol models with the 3.0‑litre 6G72 often used multi‑point EFI, and diesel models (e.g., 4D56T) use mechanical diesel injectors/nozzles. Some markets retained carburetted petrol options, but injectors are clearly relevant and commonly fitted on 1991 Pajeros.

On EFI petrol versions, the injectors meter fuel precisely into each intake port so the engine starts cleanly, idles smoothly, and delivers decent torque without chewing through fuel. On the diesels, the injector nozzles atomise fuel into the pre‑combustion chamber, and their spray pattern and pop pressure are vital for easy starting, low smoke, and good economy. Either way, these little valves do the heavy lifting every time the key turns.

Keeping them healthy on a 1991 Pajero is a smart move. Age, varnish, and grit can lead to dribbly spray, misfires, hard starts, pinging (petrol), or smoke and rough idle (diesel). A quality cleaner in the tank can help, but proper bench cleaning and flow testing (petrol) or pop‑testing and calibration (diesel) give real results. If an injector is electrically weak, cracked, or has a poor spray pattern that won’t correct, replacement is the go.

• Service interval guide: consider testing/cleaning around 100,000–150,000 km, sooner if symptoms show.
• Warning signs: lumpy idle, hesitation, higher fuel use, black/grey smoke (diesel), fuel smell, or hard hot starts.
• Good practice: replace injector seals/O‑rings whenever injectors are removed, always use new copper washers on diesel nozzles.
• Electrical checks (petrol): confirm correct injector resistance and a solid 12 V supply with a clean, consistent pulse from the ECU.

For driveway care, keep the fuel system clean: stick to reputable fuel, change the fuel filter on schedule, and don’t run the tank to fumes. When pulling injectors, depressurise the rail (petrol), label plugs, and torque everything to spec from the workshop manual. A well‑sorted set of injectors helps a 1991 Pajero feel eager, tow better, and use less fuel — whether it’s a V6 petrol on EFI or a trusty turbo‑diesel.

Popular questions

How can someone tell if their 1991 Pajero’s injectors are playing up?
Common give‑aways are rough idle, stumbles on take‑off, higher fuel use, or a fuel smell (petrol). Diesels may show hard starting, more smoke, and a harsher knock. A proper diagnostic — scan for codes on EFI models, plug balance tests, flow testing (petrol), or pop‑testing (diesel) — will pinpoint the culprit rather than guessing.

How often should fuel injectors be serviced?
There isn’t a strict schedule, but having them tested and cleaned around the 100,000–150,000 km mark is sensible, especially if the vehicle works hard or has unknown history. Always replace filters on time and consider periodic use of a reputable cleaner to slow build‑up.

Do diesel injectors on a 1991 Pajero need calibration?
Yes. Mechanical diesel nozzles benefit from pop‑testing and calibration to the correct opening pressure and spray pattern. If starting gets sluggish, smoke increases, or fuel economy drops, a test and set‑up by a diesel specialist can restore proper performance.