TD5 MAF Replacement

[reid25]

Hi All,

Have run the nanocom on the car, and found that I have two faults - 1,7 Air flow circuit low, and 5,7 Air flow circuit current. Readings are 0 air flow at idle, and a maximum of about 100-110 under full load. I'm going to assume MAF is cactus - what's the recommendation these days? OEM is $450ish, and I don't want to spend that if I don't need to.

Cheers!

[Slunnie]

The Siemens/VDO/Continental unit. The manufacturer has evolved through these names, but its the same product.

[shack]

Hi All,

Have run the nanocom on the car, and found that I have two faults - 1,7 Air flow circuit low, and 5,7 Air flow circuit current. Readings are 0 air flow at idle, and a maximum of about 100-110 under full load. I'm going to assume MAF is cactus - what's the recommendation these days? OEM is $450ish, and I don't want to spend that if I don't need to.

Cheers!Your engine may actually be a 10p utilising speed density fuelling.

If this is the case and you have deleted the EGR you won't get any benefit from replacing a broken MAF.

[reid25]

Your engine may actually be a 10p utilising speed density fuelling.

If this is the case and you have deleted the EGR you won't get any benefit from replacing a broken MAF.

It's a 99 with MSB so I assumed it would be 10p. I have an EGR delete kit ready to go, do you suggest just deleting that and keeping the MAF unplugged? I got confused reading the SierraFerry MAF thread haha. Also was planning on getting an NNN with a tune, would this tune be a MAFless one then?

[reid25]

The Siemens/VDO/Continental unit. The manufacturer has evolved through these names, but its the same product.

Cool. I noted some older threads suggested OEM only thats all

[shack]

It's a 99 with MSB so I assumed it would be 10p. I have an EGR delete kit ready to go, do you suggest just deleting that and keeping the MAF unplugged? I got confused reading the SierraFerry MAF thread haha. Also was planning on getting an NNN with a tune, would this tune be a MAFless one then?I'm not going to get into the OEM/genuine vs Siemens/VDO/Continental or whatever.

But if you are 10p with MSB or NNN with the correct tune on it and no EGR, you will simply be wasting money.

The MAF on a 10p tune is mainly required for controlling the EGR.

The only time a MAF is useful on a 10p without EGR is for error checking the MAP/IAT.

I wouldn't bother replacing.

[reid25]

I'm not going to get into the OEM/genuine vs Siemens/VDO/Continental or whatever.

But if you are 10p with MSB or NNN with the correct tune on it and no EGR, you will simply be wasting money.

The MAF on a 10p tune is mainly required for controlling the EGR.

The only time a MAF is useful on a 10p without EGR is for error checking the MAP/IAT.

I wouldn't bother replacing.

Just to really spell it out for me - do I unplug the MAF as its not performing correctly? I feel as if I'm missing some power and am hoping this may make a difference

[shack]

Just to really spell it out for me - do I unplug the MAF as its not performing correctly? I feel as if I'm missing some power and am hoping this may make a differenceI shall.

You can unplug it or leave it plugged in, it'll make no difference.

If you are noticing lag when coming out of low power request cruising, it could be because of the EGR trying to work with a faulty MAF.

More likely though it's that the EGR could be leaking, I.E. stuck partially open.

Unplug the MAF if it makes you feel better!

[reid25]

I shall.

You can unplug it or leave it plugged in, it'll make no difference.

If you are noticing lag when coming out of low power request cruising, it could be because of the EGR trying to work with a faulty MAF.

More likely though it's that the EGR could be leaking, I.E. stuck partially open.

Unplug the MAF if it makes you feel better!

Haha thank you. I better get on to the EGR delete then!

[Slunnie]

Cool. I noted some older threads suggested OEM only thats all

I'm pretty sure they are the OEM.

But Shack is far more informative about the value of replacing it than me.

[shack]

Yeah I think they are OEM, Fery always says "genuine only" which is serious money.

I've found the OEM ones to be pretty good.

If anyone has a good genuine one, I'm happy to flow test it against an OEM and make the results public.

Just to quickly explain, the MAF provides the engine ECU with total flow of air going into the engine in weight, the ECU then uses this to calculate the maximum amount of fuel that can be injected without going outside stoichiometric AFR. This is to provide a clean burn and reduce emissions.

A MAF will generally fail by under reading, but I have seen 1 that failed over reading.

But most failed ones simply don't read anything at all.

[sierrafery]

Just to really spell it out for me - do I unplug the MAF as its not performing correctly? I feel as if I'm missing some power and am hoping this may make a difference
I have nothing to add to what @shack have already explained about the MAF on a 10P, if you have the EGR delete kit fit that ASAP then cut out all the internals of the MAF as to be just like an empty tube for the best air flow and let it unplugged but check fuse F2 anyway cos if it's blown the MAF shows zero while the wastegate modulator is on the same circuit as well and then you can have power issues without other code, also if the EGR was there untill now clean well the MAP sensor cos it might be full of gunk, the pressure sensor is in it's bottom near the probe make sure that little hole is very clean but use only spray as to not hurt it, the visible probe is for IAT reading.

[reid25]

I have nothing to add to what @shack have already explained about the MAF on a 10P, if you have the EGR delete kit fit that ASAP then cut out all the internals of the MAF as to be just like an empty tube for the best air flow and let it unplugged but check fuse F2 anyway cos if it's blown the MAF shows zero while the wastegate modulator is on the same circuit as well and then you can have power issues without other code, also if the EGR was there untill now clean well the MAP sensor cos it might be full of gunk, the pressure sensor is in it's bottom near the probe make sure that little hole is very clean but use only spray as to not hurt it, the visible probe is for IAT reading.

Awesome, thanks so much. will get onto those items.

[Kaaaiju]

Pitty VDO don’t make the MAF anymore