How to replace the RB20DET Mass Airflow Sensor (MAFS) - R32 Skyline Tech
It's not super common for the RB20DET MAFS to die, but when it does you'll know it immediately. This Skyline was running perfectly when we took delivery, but once we parked it and tried to start it again it would immediately die. Diagnosing the MAFS won't be the topic of this article, but will be covered in the future. However, the way we found this particular one was by unplugging the Mass Airflow Sensor and the car was back to running again, albeit with a high idle.
Getting the sensor out of the car
This is really easy if you have an aftermarket pod air filter, but in this case the car is 100% stock. Still, getting to it is relatively easy but takes some small hands. I don't have small hands.
The MAF sensor is circled in green, and the 5 clips holding it in are pointed to with the red arrows.
- Jack up the car and put it on jack stands. You can skip this step if you want but trust me, your back will thank you. You don't have to bend over as far and it will also be easier to climb under the car when you inevitably drop your tools.
- Unplug the plug circled in green.
- This is the only "hard" part of the entire removal. Below the plug circled in green there will be a single clamp holding the MAF sensor to a silicone coupler. Loosen that clamp. The area around it is extremely tight so getting a flathead screwdriver in there is pretty tough. I was able to lower it in from the top and turn it from the side, and then get the remaining turns with my hands.
- Once the clamp is loosened, unhook the 4 clips on the stock airbox. There are red arrows pointing to those in the picture above.
- Grab the airbox and pull away from the engine, and out the side.
You MAF will come out with the top of the airbox, and look like this:
Remove the four 10mm bolts holding the MAFS to the airbox and replace it with your working sensor.
This is a good time to replace the air filter or remove the entire airbox and replace it with an aftermarket AEM filter.