Mass air valve (1 Viewer)

[Baycott]

I have a friend stuck in Spain with a broken down 2011 Fiat Ducato van. The Fiat diagnosis said it was the Mass air valve and fitted one to no avail. They are now saying it is the ECU and have to wait till next Thurs for a replacement. However, my friend has noticed that the MAV has not been put in the same way round as the old one. I don't know anything about engines but said I would ask you clever lot.

Any ideas folks??????

 

[gus-lopez]

If it is the mass air valve ( Maf) then unplugging it will allow the vehicle to run on the 'fail safe'settings. These are built in to allow normal running to get you out of trouble. If your friend just unplugs it then it should run , to all intents & purposes , normally.

If it doesn't , then it is something else.

 

[gus-lopez]

On any I have changed ,I didn't think it was possible to insert them the wrong way round ?

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[olley]

According to this vid, it can't be fitted wrongly. Skip to about 1.30 mins

 

[ivorantony]

I think you mean mass airflow meter, it tells how much air is flowing into the engine,
MAP sensor measures pressure in the inlet manifold,

 

[Baycott]

According to this vid, it can't be fitted wrongly. Skip to about 1.30 mins

Apparently it looks like this

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[wizza]

I would be checking the harness and connectors around the fuse box they can corrode and rub against the brackets that support the harness. You need to remove the headlamp for easy access.

 

[Baycott]

I would be checking the harness and connectors around the fuse box they can corrode and rub against the brackets that support the harness. You need to remove the headlamp for easy access.

The problem is that he has had this unit replaced by a dealer in Spain and it looks like they have fitted it round the wrong way.
ie the yellow tab is on the engine side (left in the pic) whereas it was on the right (as pic) before.

 

[gus-lopez]

If they have changed the whole tube with the maf in it then yes it would be the wrong way around if the tab was on other side before.Then it wouldn't work. Normally they have an arrow on them but they are usually underneath . Also that one looks like it can actually be put in either way around , which is unusual .Normally they are idiot proof & can only be installed in one direction. Just unplug the wiring plug & try it then.

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[gus-lopez]

Apparently it looks like this
View attachment 135084

Having just looked at new ones on ebay ,they are 80mm dia inlet & outlet & looking at plug position which is just slightly nearer one end than other I'd have my money on that being in the wrong way around.
As I said before ,quickest way to show whether it is the maf when in limp mode is to unplug it. start up & it should run as normal. What it is doing is reverting to the safe settings . i.e. fuel is a bit richer etc;

 

[Baycott]

Having just looked at new ones on ebay ,they are 80mm dia inlet & outlet & looking at plug position which is just slightly nearer one end than other I'd have my money on that being in the wrong way around.
As I said before ,quickest way to show whether it is the maf when in limp mode is to unplug it. start up & it should run as normal. What it is doing is reverting to the safe settings . i.e. fuel is a bit richer etc;

Not sure what the symptoms are as we are only able to communicate by text. He just asked me to enquire if it could be fitted the wrong way round. I think it is running intermittently. Sometimes will, sometimes won't.

Edit: Now I think about it I think he said it was running normal then had a lack of power although still running.

Thanks for your input Gus.

 

[Lofty1]

If it runs but lacks power then the MAS is not working and reduces fuel intake as all have said reverse it a five min job

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[Louis]

These can be fitted wrong way round. Lack of power is most common, but driveable. As already mentioned they have an arrow to indicate airflow

 

[Baycott]

He is going to speak to them in the morning. I will let you now how they get on.
Thanks everybody for your help.