Renault Master - Mass airflow sensor

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Sat 31 Oct 2015 21:36
Renault Master - Mass airflow sensor - fstormin

I operate a 2007 registered Master van fitted with the 2.5 litre cdi 100 GU9 engine.

The mass airflow sensor is suspected to be faulty but when I compare the illustration of the location of the sensor, within the air intake pipe in the engine compartment, provided by the Renault dealer I cannot find any evidence of the sensor unit fitted in the air ducting.

Are all Master vans of this build year fitted with a mass airflow sensor and, if so, is it installed elsewhere than in the air intake pipework?

Regards

Norman

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Sun 1 Nov 2015 19:52
Renault Master - Mass airflow sensor - hardway

They all have MAF's fitted.

And if memory serves they're kind of fitted backwards,

by that I mean the multiplug isnt apparent.

So the MAF unit just looks like some plastic ducting.

Find the MAF plug and you'll find the MAF.

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Mon 2 Nov 2015 11:54
Renault Master - Mass airflow sensor - Railroad.
What symptoms do you have? A faulty mass air flow sensor will not prevent the engine from starting or running, but it will have an effect on engine performance if it's not working properly. It works in a very simple way, and the most likely fault with it is dirt and contaminates on the hot blade. Buy some Air Intake cleaner and clean the sensor hot blade before you buy a new one. This will usually cure your problem.

The ECM supplies the MAF with 5v. This heats up the hot blade. Air passing over the hot blade forces it to cool, and so the ECM has to heat it again. The more it cools the more it's reheated, and the more air the ECM knows is passing through it. If the hot blade is coated in dirt the passing air will have less of a cooling effect, and so the ECM will not have to reheat it so much. This will lead the ECM to think there isn't much air passing, and so consequently it will not supply much fuel and engine performance will be reduced. In this case it's unlikely a fault code will be generated because as far as the ECM knows nothing is wrong.

The sensor should only need to be replaced if the hot blade is damaged or the sensor has an electrical circuit fault. This would usually generate a fault code.
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