Quick MAF question

Hi all.....Just a quick one. My MAF meter is duff and has been since I bought my Disco but I've just drove it on. Now the NCT( MOT on steroids) is due and I was wondering if a failed Air Flow Meter would affect fueling and, subsequently increase emissions. I had a look at the previous test certificate and noticed that it just about passed the emissions test that time. I have since de-EGR'd which should bring emissions down but will I have to rush out in the morning and fit a new MAF meter before she is brought to the test centre?

Thanks all....

you should have replaced it not only for emissions but for the running of the engine and sake of the consumption... why would you risk? ... it depends much on some other elements too how it will affect the emissions but certainly it does, more or less... the depression controll valve is important too(that mushroom kind of thing after the MAF) cos if it's old even if it works it lets more crankase gasses through than it should, the condition of the AAP(in the airbox) and the MAP sensors( i mean how dirty they are) affects the emissions too... strangely the EGR would not affect the MOT as they measure the concentration of NO3/opacity which is regardless of EGR.

in a nutshell the management must be well maintained to have good emissions, if you want to improve things a bit put some gasoline in the diesel(max. 5%) and make sure the engine is very hot when you get to the MOT station.

Thanks for the technical info sierraferry.....I knew the fueling would be affected alright but was kind of able to live with it because of short daily journey's. I have a nanocom and was aware that the MAF meter was duff. I cleaned up the little sensor inside and this raised the airflow reading slightly but still far short of the norms...Idle was 4 whatever the air flow measurements are. After I cleaned it this went up to 28 units of air. I think the reading should be over 100 units at idle....On my way to get a new one and into test centre later....

Thanks again.

the good reading is around 60 at idle and up to 600 at full throttle... if you kept it so for a long time maybe you paid the price of a new MAF for the extra consumption untill now.... and you didnt even have a well running engine

Just make sure you get a genuine one. No GEN are crap...!

andycudworth said:

Just make sure you get a genuine one. No GEN are crap...!

Click to expand...

ditto when I bought my d2 td5 it had a non gen one fitted, genuine ones have two hot film resistors whereas the ****ter has one hot film resistor.

( a strip of wire that is heated and according to how much airflow passes over it, it changes resistance telling the ecu how much air the engine is using)

and the other resistor is just a fixed value carbon film electronic component resistor soldered in its place which will give a false reading and show air flow meter fault codes