So, tonight I decided to clean my Mass Air Flow sensor, as it is something I havent done yet. After 2 years of hard offroad use, the sensor was just CAKED with dust and dirt. The truck now idles smoothly and runs much better. I wont be surprised if it gets much better gas mileage as well.
One major reason to do this.. the Nissan EFI system relies heavily on the MAF to calculate fuel delivery at lower RPMs. From what I know about the older VG30 EFI systems, the MAF is/was used up to 2800 rpm, at which point the system switches over to the O2 to calculate the mixture to deliver in closed loop. So, a dirty MAF causes driveability problems, uneven idle, an inaccurate mixture for most driving conditions at the very least.
So, heres how to clean your MAF. And the best part, it only takes 15-20 minutes to do this with only a screwdriver at the minimum.
What Vehicles is this for?: Basically any 1990+ trucks with multiport EFI
- medium flathead screwdriver
- 8mm socket with short extension
- A bottle of 90%+ Isopropyl Rubbing Alcohol
- Some Q-Tips
1. When I did this, I removed the upper half of the airbox to ease the removal of the MAF. So, First, unclip the clamps holding the airbox together and remove your air filter. Set it aside.
2. Now, Remove the MAF plug as shown. If yours still has the wire clip on it, pop it out of place with a small flathead screwdriver and then pull off the plug.
3. Next, loosen the clamp on the hose that attaches to the MAF unit. This is where the 8mm socket comes in handy:
4. Now, locate the two screws on the MAF unit. These hold the MAF sensor to the body of the MAF unit. Use the flathead screwdriver to remove these, carefully holding the sensor in place while you do it.
5. Now, carefully lift the MAF sensor straight up and out of the MAF unit. Be very gentle with this unit. It is VERY easy to damage the tiny wires on the sensor end.. DO NOT TOUCH!
6. Take the MAF sensor to your workbench and lay it sensor side up. Go grab your cleaning supplies:
7. Here is an ultra-closeup image of what my sensor looked like! LOOK at the dust and dirt build up!
8. Now, take your rubbing alcohol and pour a capful of alcohol to dip your Qtips in. Use the Qtip to carefully swab both wires of the sensor. Be careful not to use much if any pressure on the sensor, let the Qtip and alcohol soak up the dirt. Dont forget to clean up the rubber O ring around the bottom of the "tower". Here is what I removed off mine in the first pass. I ended up using both ends of 3 qtips to get it clean:
9. And here is the result ... a clean MAF sensor! pretty big difference, huh? (BTW, you can visibly see that the wires got bent a little when cleaning... again, I can't stress enough: be very gentle with the sensor when cleaning!)
10. Let all the alcohol evaporate off the sensor and reinstall it in the MAF unit housing with the two screws..
11. Reinstall the MAF unit/upper airbox into the intake hose and tighten the clamp back down with the 8mm socket.
12. Plug in the MAF sensor plug.
13. Reinstall your air filter.
Congratulations, you just cleaned your MAF sensor! Now go fire the truck up and see how it runs. It may take 20-30 minutes of driving for the ECU to recalibrate to the MAF signal, but if yours was as dirty as mine, your truck should run a lot better now.