Question 1

What sensors and solenoids commonly fail on the RX8?

Accepted Answer

The RX8 is known for failures in several key components, including the oil pressure sensor, coolant temperature sensor, map sensor, oil control valve solenoids (which govern variable valve timing on Series 2 models), and the idle air control valve. These are high-priority items to monitor as the engine ages, since a faulty reading or stuck solenoid can affect fuelling, idle quality and engine prot

Question 2

How do I know if my RX8 coolant temperature sensor is faulty?

Accepted Answer

A failing coolant temperature sensor on the RX8 typically causes erratic temperature gauge readings, poor cold-start fuelling, rough idle or a check engine light. Because the ECU relies on this sensor to calculate fuel delivery, a faulty unit can contribute to the running issues and flooding problems that rotary engines are particularly sensitive to.

Question 3

Can a faulty map sensor affect my RX8's performance?

Accepted Answer

Yes. The map sensor feeds the ECU with intake manifold pressure data used to calculate injector pulse width. A failing map sensor on the RX8 can cause hesitation, poor throttle response, rough running or incorrect fuelling at higher revs, all of which are amplified by the rotary's sensitivity to fuel delivery accuracy.

Question 4

What do the oil control valve solenoids do on a Series 2 RX8?

Accepted Answer

On Series 2 RX8 models, the oil control valve solenoids regulate oil flow to the variable valve timing (S-VT) system on the intake side. If a solenoid fails or becomes clogged, timing control is lost, which typically results in a check engine light, reduced response in the lower rev range and a logged fault code related to the S-VT system.

Question 5

Should I replace RX8 sensors with genuine OEM parts or aftermarket alternatives?

Accepted Answer

For sensors that directly inform engine management - such as the coolant temperature sensor, map sensor and oil pressure sensor - genuine OEM parts are strongly recommended. They are calibrated to the factory specification the ECU expects, ensuring accurate readings. Aftermarket sensors vary in calibration accuracy, which can introduce the very symptoms you are trying to cure.

Question 6

Will replacing a faulty sensor fix my RX8's check engine light?

Accepted Answer

Replacing a confirmed faulty sensor will resolve a fault code caused by that sensor, but it is important to diagnose the specific code first. Some codes that appear sensor-related can stem from wiring, connectors or upstream issues, so confirming the root cause before replacing parts saves time and money.

Question 7

Are genuine Mazda sensors for the RX8 still available?

Accepted Answer

Many genuine Mazda sensors and solenoids for the RX8 remain available as new old stock or current genuine parts, though availability for some specific components is gradually reducing as the model ages. Sourcing genuine parts now rather than waiting is a practical approach for any RX8 owner planning preventative maintenance.

Sensors & Solenoids