Parts for your 1990 Mitsubishi Pajero-Throttle position sensors

1990 Mitsubishi Pajero Throttle Position Sensor

Based on Mitsubishi’s factory literature and well-known repair manuals, the 1990 Mitsubishi Pajero does use a throttle position sensor (TPS) on petrol models fitted with electronic fuel injection, such as the 3.0‑litre V6 (6G72) and markets that received ECI‑Multi petrol setups. See Mitsubishi Pajero/Montero Factory Service Manual (Group: Fuel and Engine Control – ECI‑MULTI, TPS inspection/adjustment), the Haynes Mitsubishi Pajero/Montero 1983–1996 manual, and the Mitsubishi ASA electronic parts catalogue for TPS listings on 1990 V6 EFI variants. Carburetted 2.6‑litre petrol and mechanically injected diesel versions typically don’t use a conventional TPS for fuelling. Some diesels may carry an accelerator position or throttle switch purely to help manage EGR or idle‑up, not injection timing or quantity.

On EFI‑equipped 1990 Pajeros, the TPS is bolted to the throttle body and tells the ECU exactly how far and how fast the throttle is opening. That signal helps the ECU handle spark timing, injector pulse width, decel fuel cut, idle control, and even shift behaviour on autos. When it’s doing its job, throttle response feels clean and predictable, cold starts behave, and the gearbox doesn’t hunt on part throttle.

Typical signs of a crook TPS include a flat spot off idle, surging at cruise, a hanging or wandering idle, harsh or delayed shifts (auto), higher fuel use, or the ECU logging a fault code. Because it’s a simple potentiometer, wear on the internal track can cause dead spots, especially right off idle where it spends most of its life.

There’s no fixed replacement interval, but it’s smart to check it as part of a major service every 40–60,000 km. Easy wins include cleaning the throttle body and ensuring the TPS connector is clean and tight. A quick multimeter sweep test across the signal wire should show a smooth rise from roughly half a volt closed to around 4–5 volts at wide open throttle, any drop‑outs or spikes mean it’s time to replace it. Don’t wind the throttle stop screw—use the TPS’s slotted mounting holes to fine‑tune closed‑throttle voltage per the workshop spec.

Replacement is straightforward: disconnect the battery, unplug the sensor, undo the two screws, swap the unit, align the drive tang, lightly snug the screws, then set the base position/voltage. After refitting, clear the ECU’s keep‑alive memory (battery disconnect), start the engine and let it idle to relearn. Always match the new sensor to your exact engine code and plug style, as early Mitsubishi looms and throttle bodies vary.

Does a 1990 diesel Pajero have a TPS?

Most mechanically injected 1990 diesels don’t use a TPS for fuelling. Some trims do have an accelerator position or throttle switch to inform EGR or idle‑up systems, but it’s not the same as the EFI petrol TPS driving fuel and spark strategies.

How do you test the TPS on a 1990 Pajero V6?

Back‑probe the signal wire with ignition on and slowly open the throttle. You’re looking for a smooth voltage sweep from about 0.4–0.7 V closed to roughly 4–5 V wide open. Any sudden drops or flat spots suggest internal wear. Check the manual for exact pin IDs and specs.

Do you need to reset the ECU after replacing the TPS?

On this era Pajero, a basic reset is enough. Disconnect the battery for 10–15 minutes, reconnect, then start and let it idle without accessories for several minutes so it can settle its idle strategy. A short drive cycle helps it refine trims.