Air Flow Sensor

[Notso]

Recently noticed a slight increase in fuel useage/kilometre, nothing much but noticeable.

Anyhow I decided to have a look at the Air Flow sensor. Mainly because it's the only one I can find??? On removing it I found it was black and coated with dust.

The Air Cleaner looked OK with maybe a small amount of dust above the rubber seal.

I cleaned the sensor with Electronic Parts Cleaner (now nice and shiny again)and replaced it after checking out the rubber seal on the Air Filter. it seems Ok. I've wiped the whole box out with a damp cloth including the sides of the filter so I can check it later on to see if it's leaking dust. I'll now have to observe the Fuel economy and see if it goes back to normal.

[Sapient]

Snap Notso,

Pulled mine out today as I was reoiling the Ubifilter anyway, and had noticed a drop in fuel economy.

Same condition as yours also, coating of black dust build-up. Cleaned mine with parts cleaner, and had noticeable improvement in mid range response and high end revs already. Will monitor economy but I am already certain it will improve.

[Notso]

Just to add some info.

Thought I'd check the manual and found that there are two little wires up inside the Sensor which I'd missed on the first occasion so I removed it again and cleaned them as well, they didn't look too bad but noticeably cleaner now. Have to take if for a drive and see what the result is.

[sam]

I noticed dust on the intake side of the air filter on our big trip to the Kimberly's last year so will check the air flow sensor asap.
Still reckon the ML NEEDS a bigger and better air box

[scubapro]

guys what brand of cleaner are you using & where can I buy it please?

[Notso]

It is "CRC" Brand Automotive Electronics cleaner I got it from from Supa Cheap Auto but I imagine any electronics or automotive spare parts place would have it.

It is a highly Volatile luiquid under pressure in the can and evaporates very quickly once released from the Pressure Pack.

[sam]

Cleaned mine and yes it was rather dirty so will be interesting to see if it makes any diff

[brenze87]

just thinking are any of you guys running an aftermarket air filter like the uni filter. thought that the oil from the filter might be causing this build up?

[sam]

No I'm still running the factory filter but I'm going to see if a Hi Lux air box might fit as it has heaps more surface area to the filter .

[Notso]

Mine's totally stock standard everything.

[subi_man]

I got 5 mins to check mine today, and was surprised to find it was identical to the AFM used on turbo petrol Subaru's. If this is indeed the case, here's what I know about them.

The visible "bulb" sensor (circled in red) only measures air intake temp. The sensors for the AFM are up inside the tube (yellow arrow). Like notso, I use a non-conductive electronics cleaner and blast them clean as much as possible. You need to be careful with these things, a replacement Subaru one used to be around $700

There was no sign of oil from my Unifilter, just a layer of grime on all the sensors. Have not road-tested to see if there is any noticeable difference with a clean AFM.

Cheers

[Buzzy]

Its Ok just to spray the entire thing?

[subi_man]

That's what I did Buzzy

[Jitsukablue]

So that's why MMAL wouldn't supply a unifilter... are these hot wire MAF sensors? IE thin metal strips/wires across the bore?

[Notso]

Yep, two of them up inside the ducts in the AFM, there is a temperature sensor on the outside which appears quite robust but the two small wires up inside are very thin.

[sheepo]

well i gave the air flow sensor a spray with the elect cleaner wow what a differents fuel economy seems better and bit more response well thats what it feels like any way
cheers peter

[Adz]

Im assuming these parts would be the same on both diesel & petrol?

Has anyone tried this on a petrol model?

[sierra]

Sam,

Here it is. You should remember this, your post is just before this one.

The pic shows the sensor in the aircleaner, mine looked identical to this and that's where it was.
Scoop and probe.

I got 5 mins to check mine today, and was surprised to find it was identical to the AFM used on turbo petrol Subaru's. If this is indeed the case, here's what I know about them.

The visible "bulb" sensor (circled in red) only measures air intake temp. The sensors for the AFM are up inside the tube (yellow arrow). Like notso, I use a non-conductive electronics cleaner and blast them clean as much as possible. You need to be careful with these things, a replacement Subaru one used to be around $700

There was no sign of oil from my Unifilter, just a layer of grime on all the sensors. Have not road-tested to see if there is any noticeable difference with a clean AFM.

Cheers