Parts for your 1991 Nissan Primera-Knock sensor

1991 Nissan Primera knock sensor — is it fitted and what does it do?

Based on the Nissan Primera P10 Factory Service Manual (EC/ECCS section) and Nissan FAST parts catalogues for the 1990–1992 P10 range, the petrol engines used in the 1991 Primera — GA16DE, SR20Di and SR20DE — are equipped with a block-mounted knock sensor (commonly referenced under Nissan part family 22060-30P00). The CD20 diesel variant does not use a knock sensor. So for 1991 petrol Primeras, this part is relevant and serviceable.

The knock sensor on a 1991 Nissan Primera is a small piezoelectric microphone that bolts to the engine block and listens for pinging (detonation). When it hears knock, it sends a signal to the ECU so timing can be trimmed back on the fly. That protects the pistons and keeps the engine running sweet as under Aussie and Kiwi conditions — hot days, steep hills, and the odd tank of ordinary fuel.

On these P10 petrol engines, the sensor helps the ECU optimise spark advance for power and economy while staying out of the danger zone. If the knock sensor or its little sub‑loom goes crook, you may notice a flat spot, lazy acceleration, higher fuel use, or the ECU dropping into a conservative timing map. The ECU can flag a fault (often seen as Code 34 on Nissan self‑diagnostics) even if the dash lamp doesn’t light in all markets.

It’s not a scheduled replacement item, but at this age it’s smart preventative maintenance to inspect it when you’re under the bonnet for bigger jobs. The sensor sits on the block under the intake side, access varies: GA16DE is tight but doable from above, SR20DE/SR20Di often needs intake bits moved or access from underneath.

• Use an OEM‑style sensor, cheap copies can be noisy or deaf.
• Clean the block’s mating pad, install dry, no sealant.
• Tighten the single bolt to 20–25 N·m with a torque wrench.
• Inspect the sub‑harness for brittle insulation or greened pins, replace if suspect.
• Route the loom away from exhaust heat and sharp edges.
• After fitting, clear ECU codes and take a gentle test drive so the ECU can relearn.

If the engine still pings on decent 95+ RON fuel after replacement, look to basics — coolant temp sensor accuracy, vacuum leaks, carbon build‑up, or timing that’s been set too far advanced. But when the sensor and wiring are healthy, the P10’s ECU does a tidy job of keeping detonation at bay while letting the car pull cleanly through the revs.

Where is the knock sensor on a 1991 Primera?

On GA16DE and SR20DE/SR20Di petrol engines, it’s bolted to the engine block on the intake side, roughly mid‑block height. You’ll usually reach it from under the car or by moving the intake plumbing for a clear shot. Look for a single‑bolt, doughnut‑shaped sensor with a short sub‑loom.

What are the symptoms of a bad knock sensor on a P10?

Common signs include a lack of go under load, worse fuel economy, and detonation protection kicking in too often. The ECU may log a knock sensor circuit fault (often read as Code 34 via the self‑diagnosis procedure). Wiring damage is just as common as a failed sensor.

Does the 2.0 diesel Primera use a knock sensor?

No. The CD20 diesel doesn’t rely on spark ignition and doesn’t use a detonation‑type knock sensor in the way the petrol GA16DE/SR20 engines do, so this part isn’t applicable to that variant.