Checking and cleaning MAF sensors

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Originally Posted by myzathreeby

Hi YNOT
Just a question.. What is the mass air sensor actually detecting?
and what is it controlling.
Why would it affect the engine power.
I am assuming you only get the MAF sensor on the 3.0 turbo so I'm guessing it has something to do with a fault on the turbo or blocked filter. which causes a loss of power.
Cheers John

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As robo has said above, the MAF sensor measures the amount of air that is entering the engine and sends the info to the cars computer which then calculates how much fuel to add in order to get the correct air/fuel mix.
All EFI cars have a MAF sensor.

Lucas

Interesting thread. My GUIV idles well but a bit roughly, especially when it drops into overdrive below 2000 rpm and I feel that I don't have enough power when I accelerate up certain hills on my journey to work. I would be fairly sure that the previous owner has never had the MAF cleaned. So if I do this can I expect:

*smoother engine through the range?
*improved fuel consumption?

YES on both counts if the maf is the cause.

Also, efi petrol throttle bodies can be a bit of a problem also.
Can usually be cleaned on car well enough to correct clear blockages but must be done with stone cold engine.
Cheers.

Thanks YNOT and and everyone contributing to this
Information like this, make (for me) the muddy waters of hitech motors a little less murky.
from a lo tech new comer.

Pete.

My sensor has no voltage on it, where is the fuse situated (which one is it?) that supplies power to the sensor?

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Originally Posted by Bigrig

Unless you're trying to clear error logs from the ECU - I left mine overnight to be sure when I had the coolant temp sensor problem, but I believe the manual states it can take up to 24 hours for a manual reset (battery disconnect) to clear all errors.

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G'day Bigrig,

I have a 2.8 TD GU Patrol, owned it now for 6 years. Recently had blown head gasket and 6 stuffed exhaust valves. Anyway, the point is, when she blew the coolant out, took her to 4WD workshop to evaluate what the prob was. The eng overheat warning had gone off and logged it'self on the pc.
After disconnecting the battery for 24 hrs, as everyone seems to advise, on reconnecting the fault was still there, at the end of the day, I had to visit the local auto elec who hooked up his computer and cleared the pc memory.
I was advised by him, the only way such logs can be cleared is with a pc hooked up and manualy deleted.
I witnessed everything he did myself, so am continuosly puzzled by comments that claim to delet faults by disconnecting battery.

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Originally Posted by Conroy22

My sensor has no voltage on it, where is the fuse situated (which one is it?) that supplies power to the sensor?

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There is no fuse, voltage is supplied by Engine ECU, it is only around 5V.
Cheers

mine seems to have no power some times, cleaned the mac but no difference. forgot to do reset though. second gear foot flat it just goes nowhere if revs are low. this normal?

this is not quite true some efi vehicles had a MAP sensor (Manifold Absolute Pressure sensor).
cheers mav

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Originally Posted by taslucas

As robo has said above, the MAF sensor measures the amount of air that is entering the engine and sends the info to the cars computer which then calculates how much fuel to add in order to get the correct air/fuel mix.
All EFI cars have a MAF sensor.

Lucas

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