MAF Sensor issues

Oddball8500 · Post by **Oddball8500** » 02 Mar 2018, 03:49

Hi all,

Hope you're all enjoying the snow!

My girl has had an issue with the rpm needle twitching for a while and after a diagnostic with Vida/Dice it showed MAF sensor so I swapped it with an old one I had from an Alfa 156 and all was good including fuel consumption so I left it for 6 months but now Vida is showing an MAF sensor issue with poor air flow. So I bought a cheap new one from eBay and all was good apart from doing only 45 miles on £15

So I swapped the old Alfa one back and fuel consumption returned to normal!?? I then bought another OEM one secondhand from a guy on FB that had the same model as mine although a 2002 model (mines a 2001 C70) that the aux belt had snapped and ruined pulleys etc. So I took the risk and bought the complete MAF and housing for £17 inc p&p ( not too bad I thought) but again fuel consumption has gone high!

So I finally bought a brand new OEM MAF insert for £58 and yet to fit it as we had lots of snow yesterday and planning to swap it over today but my question is......would a faulty MAF sensor cause her to drink fuel? She also has a very slight judder at 2800rpm sometimes on the motorway at 70 MPH and this was worse if I had the fan blower on full but has almost disappeared now!

I have run Vida again and apart from the clutch pedal sensor and the MAF sensor issue there is nothing else apart from a roof sensor is coming up as an issue with the engine so I'm stumped.

I'm hoping that when I get the new new one in today the issue with resolve itself but if anyone has any ideas please let me know.

Thanks

Si
P.S if anyone needs a diagnostic doing in Cornwall for free let me know.

Post by **abscate** » 02 Mar 2018, 05:10

Usually the MAF code comes from an air leak into the system somewhere rather than a failure of the MAF. EU does have different engines and engine management systems we aren't so familiar with , though.

The wrong MAF can definitely screw up your gas mileage

Can I link this post to the " help,a neighbor thread" to advertise your generosity?

We are flattered that the UK named a region after Cornwall, NY

Oddball8500 · Post by **Oddball8500** » 03 Mar 2018, 08:21

Hiya, thanks for the info, I will look into a air leak possibility.

And please feel free to add me to the help a neighbour etc. I do a lot of mobile diagnostics not just on Volvos

The wrong Alfa MAF worked fine and the mileage per gallon was good but I knew it was not the correct one and found after putting the correct one in (first second hand and now the brand new OEM insert) the idle is worse and drops from 840 to 800 and sometimes jumps to 900 rpm (I have pics from the diagnostic and will try and upload) so I'm confused with this as surly the new one should not make it worse!?

Any other ideas why the idle would be fluctuating?

Thanks

Simon

Post by **abscate** » 03 Mar 2018, 09:02

It could be the wrong MAF was not recognized by the ECU and it just rAn from the lookup table. I ran 200 miles like this once and got the same gas mileage as with the MAF hooked up

Post by **wizechatmgr** » 03 Mar 2018, 13:13

If the MAF is unplugged, does the idle still surge? If so, odds are it isn't the MAF causing that particular issue.