How To Clean the MAF Sensor On a 4WD

I’d been having problems with oil leaking from the turbo in my Mitsubushi PB Challenger and had also noticed a significant decrease in fuel economy. This was coupled with an increase in black smoke blowing from my exhaust under moderate to light loads.

So To Clean a Mass Airflow Sensor You need to remove the MAF which is located between the Turbo and Air Filter being careful not to drop anything into the turbo. Once removed use a Mass Airflow Sensor Cleaner spray to clean the sensor and refit. You should see an decrease in black smoke and better fuel economy.

In a previous post, you can read all about my turbo replacement, but I’d also been told that cleaning the MAF sensor might also make some difference in regards to fuel economy and black smoke. so keep reading as i got through the nitty details

What’s a MAF Sensor?

MAF stands for Mass Air Flow. So the sensor sits between your air filter and your turbo and detects the temperature, density and quantity of air flowing into the engine. The computer then calculates the correct balance of fuel and air to achieve maximum efficiency. However because the MAF sensor sits in the air-flow, and your air filter isn’t perfect, after a time it gets dirty. Once it’s dirty it can give inaccurate readings to the computer.

MAF Sensor - PB Challenger

Luckily cleaning it is very simple. But you do need to take care.

What Are Some Symptoms Your MAF May Need Cleaning

While not exclusive to a dirty Mass Airflow Sensor, i would be heading straight to my MAF if i was starting to experience some of the issues below.

  • Blowing excessive black smoke
  • Poor fuel economy
  • Rough idling
  • A distinct lack of power
  • the dreaded check engine light 

The reason to look at the MAF first and ask questions later is that its a critical component of the engine that is quite sensitive. so spending a few dollars on MAF cleaning spray could be alot cheaper then going down a rabbit hole and replacing more expensive components only to find it could of been a 5 minute fix.

Locating and cleaning the MAF Sensor

The sensor itself is very easy to locate. Open the bonnet and locate the turbo and the air filter. Between the two is a fat pipe that has a plug with electric cables running to it. It looks like this:

MAF Sensor Location - PB Challenger

Removing it is quite simple. There are a couple of screws that you remove. Then pull it out. You can unplug the electric cables as well.

Take great care once this is removed. You don’t want to drop anything down the hole that is left behind. There is nothing between the MAF Sensor and the turbo. Anything you drop in there will go straight into the turbo and the engine. They’re not designed for handling screws and nuts and screw drivers so keep those kinds of things out.

Mine looked like this. Take a look at the tiny bulb thing. That’s the temperature sensor. It’s completely covered in dust, as is the whole device.

MAF Sensor - PB Challenger

Cleaning the MAF Sensor is very easy. But you need to use the correct stuff. I went to Supercheap Autos and purchased some CRC Mass Air Flow Sensor Cleaner.

Following the instructions on this, I was able to clean the MAF Sensor quickly and easily. Give it a good squirt all over, inside and out… Afterwards it looked like this:

MAF Sensor - PB Challenger

Take a look at that little bulb thing. That’s more what it’s supposed to look like! Semi-see-through.

What’s the difference?

So the big question is, “What difference did it make?” Well before I did this, I had people behind me commenting on how much smoke i was blowing under only very minor load. Like going up a hill, or taking off from lights. My fuel efficiency was down to about 450mks on a full tank of fuel (as reported on the dash). And towing our camper trailer seemed much harder than I thought it should be.

After the turbo replacement AND the MAF Sensor clean, towning the camper is much better, I have almost no black smoke even under reasonable load and last time I filled my tank it said I had 620kms in it. Most of our driving is around the city…

So did it make a difference? Yeah, it really did! What made the most difference? Unfortunately, I don’t know because I cleaned the MAF Sensor pretty much the same day they replaced the turbo.

But my neighbour borrowed my MAF Sensor cleaner to clean the one on his Navara and he said that it made the world of difference. We’ll be cleaning our MAF sensors regularly from now on.

Would I recommend that you do it yourself? Only if you’re a handy person. It’s not a difficult job but with any mechanical activity on your car, you do it at your own risk.

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