Mass Air Flow – Cleaning the MAF Sensor

I’d been having problems with oil leaking from the turbo in my 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. 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.

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

What you’ll notice if you have a dirty MAF sensor is a decrease in fuel efficiency and more black smoke in your exhaust.

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

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.

10 Replies to “Mass Air Flow – Cleaning the MAF Sensor”

    1. thanks – great tip – I have been getting the same problem with smoke & I noticed I seemed to guzzle more fuel especially towing the trailer up the beach last time home – no turbo issues so will do this when I get home as well – I seem to be suffering turbo lag as well – any idea’s

      1. Yeah it’s a very simple job. I don’t know if the big difference for me came from the MAF Sensor clean or the turbo replacement… But it’s made a huge difference!

        From what I’ve read, turbo lag is somewhat fixed by ECU updates. Next time you get your car serviced, as the service centre if there are any updates they can apply to the computer…

        1. I should also mention that if cleaning your MAF sensor doesn’t work as well as you think it should, then there is also a warranty fix that Mitsubishi can apply if your vehicle has the specific problem. Mine didn’t but it might be worth asking about that too…

          Regards

          RossH

  1. Something you may want to look at is the exhaust gas recurculation system (EGR). On my challenger with 26k kms the EGR was caked with black gunk and the intake manifold didnt look to much better.
    Fixes are ECU mods to limit EGR valve opening and a blanking plate.

  2. I find it especially necessary to do when you place a non OEM filter in the box, a K&N air filter will throw off a lot of oil when it has been cleaned and recharged with their OEM oil. This has particular repercussions with MAF longevity and fuel use. I own a Zook and found that my car would sputter and I noticed quiet bad fuel use after the air filter was installed. A $15 can of electronic cleaner / MAF cleaner has certainly worked in my case also! Have been doing the routine MAF cleaning when I change my oil every 10K. I also put a yellow cleaning cloth as my prefilter in front of my K&N filter to act as a prefilter in the box, as I have to spend less time recharging my K&N filter and get better results – I just replace the yellow dish cloth every time I clean the MAF and that only costs me $3 for a 3 pack. Hope it helps 🙂

  3. My 09 MN has 110k 2 door diesel 4×4
    I also cleaned MAF sensor and lost about 50-70 kms per tank?
    Yet at the same time it fixed my lagging/reduced power?
    Amy thoughts

    1. Hi Dean

      Interesting. I have no idea I must admit…

      After something like this, it may take a bit of time for you car to re-learn what it’s doing. It’d be interesting to see if eventually you get your 50 to 70 back without losing the power again…

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