maf sensor disconected / working ?

[RobEvo5]

I have a 3.0l and I'm not entirely convinced the MAF sensor is working or performing as it should. I'm not competant enough with a multimeter to check output signals, but what I did do earlier today was to disconnect the MAF altogether and it made no difference to the running of the car at all, so nowthinking it is dead and the car is running only from basic map file on the ECU .

So my question is has anyone else ever tried disconnecting the MAF sensor on a 3ltr and did it make a difference to the cars running ?.

The only thing that makes my suspect my MAF is dead or faulty is a very slightly rough idle and the slightest of missfires. And thought it very odd that disconnecting the MAF made no difference. I'm happy to go buy a new one, but want to be as sure as I can that its my problem before I spent a fair wedge on a new one.

Better still has anyone in the East Sussex area have a spare one I could try for diagnoses.

Thanks
Rob

 

[lacroupade]

I don't know the Zed MAF specifically but in principle, if your car is running rough at all speeds and theres no difference with the MAF out of circuit then its almost certainly at fault. If its a Bosch then they are often prone to failure because unlike some of their competitors like Hitachi, they clean themselves by overheating the element (at switch off I think but not certain) and eventually too many cycles cause the wire element to fail.

They should be sub-£100 to replace and on an older vehicle its a good idea to do so - you certainly won't lose anything by it.

I'm sure I'm teaching my granny to suck eggs but just in case, the MAF works by passing a current through the wire element...the airflow then cools this and the resistance across the element varies as a result - that signal is then passed back to the ECU which monitors fuel input accordingly. Colder air = more oxygen, which allows for more fuel to be burnt, so the ECU will change injection accordingly.

It might be worth trying to clean the element....carb cleaner or similar solvent is best, just don't touch it unless its really carefully with a soaked cotton bud or something....