Symptoms of a knackered MAF sensor

[northyracing]

As title says really anyone know the tell tell signs if it is knackered as I am getting a judder when car is idleing but don't know if its the PCV

[Saintsteve]

Can you hear a hissing sound when you shut the engine down from the PCV valve itself?

There is a small drilling in the PCV housing and if the valve is knackered then the air from inside hisses out.

I would just disconnect the MAF, and see if the engine runs smooth.
If it runs smooth the MAF is generally ok.

[northyracing]

I have not really hear a hissing noise just I gets a lumpy idle and then once movin the car is fine so basically start the car up and unplug sensor and if it still runs smooth then it's ok

[northyracing]

Just unplugged maf and runs smooth

[bacillus]

Just unplugged maf and runs smooth

Sounds like you need another maf.

[northyracing]

i drove the car for a while got it nice and warm and it started running lumpy on idle unplugged maf and for a second engine revs dropped then back to normal and it still ran slightly lumpy at idle but noticed when driving at low speeds it felt very juddery i have replaced the dv valve but noticed one of the allen bolts but have vibrated loose would this cause a problem

[ROH ECHT]

The only real way I know of to test the MAF is to log data for the intake air mass, group 002 w/vcds, and check that with your known hp. Other than that, you can temporarily swap in a buddy's to see if it solves your issue. Your intake air mass in g/s divided by 0.80 should equal your HP. For example: my air mass is 280 g/s....280/0.8=350 HP.

[ROH ECHT]

i drove the car for a while got it nice and warm and it started running lumpy on idle unplugged maf and for a second engine revs dropped then back to normal and it still ran slightly lumpy at idle but noticed when driving at low speeds it felt very juddery i have replaced the dv valve but noticed one of the allen bolts but have vibrated loose would this cause a problem

Yes. It will run rough if the loose bolt creates a break in the seal.

[northyracing]

Been havin idle problems and juddery feeling so checked my pcv today I done the blow down the pipe test. I took it off inlet manifold side and blew down the pipe and took oil cap off and you could hear that I was blowing straight through the pcv into the engine also noticed the pipe had quite abit of engine oil in it would this suggest the pcv is naffed

[Saintsteve]

If You Can blow and Suck down that Value then it is Faulty.

[northyracing]

I had abit of oil in the pipes and also when I changed dv it was full of oil surely this ain't right either

[Saintsteve]

I had abit of oil in the pipes and also when I changed dv it was full of oil surely this ain't right either

Being full or having signs of oil in it doesnt mean its faulty.As I said if you can blow and suck, the valve inside the pcv is faulty.It has a ball valve inside.

[northyracing]

Well put it this way I had a mate blow down the pipe and I had my ear to the oil filler cap and you could hear it inside the engine so he was basically blowing straight through the pcv

[DarkSideJohn]

Not to go off topic or steal ;)
Can this effect dirty diesels too ? I have a rough idle of my 2.0 TDI, its not constant or regular , just every now and then

[northyracing]

If You Can blow and Suck down that Value then it is Faulty.

I just tried my pcv again and can blow and suck down the pipe with ease