MAF

Landyboy of birdflock · Nov 25, 2019

Hi yall, does anyone have any idea why my freelander td4 2005 will only run reasonably well with the MAF disconnected? I have tried a new pierburg maf and a second hand bosch maf but both of these, and the original maf, make it run absolutely awful, any suggestions? Thanks guys

PRO · Nov 25, 2019

how about the MAP the small sensor that checks the manifold pressure as well....

Jayridium · Nov 25, 2019

The pierburgh maf has different electrical characteristics to the original bosch one, a pierburgh maf needs a "synergy 2" tuning box to make it work. I'm guessing all three are sending signals to the ECU that are out of spec, however it strikes me as a bit of a lightning striking twice scenario if that is the case?

I've got a brand new in the box blueprint maf you could try?

Landyboy of birdflock · Nov 25, 2019

Do you think a blueprint, which I am assuming is a make, maf would make a difference Jayridium? Thanks for your offer and is there a way of testing the map sensor PRO?

PRO · Nov 25, 2019

Only checking pressure readings with diagnostics...

Landyboy of birdflock · Nov 25, 2019

Think I may just leave it disconnected, surprised it hasn't put the eml on, doesn't start or idle great though

Arctic2 · Nov 26, 2019

Do you have a synergy fitted to your car if so that could be the problem, also have you removed the EGR manifold & MAP sensor to give then a clean out ? the Bosch MAF you fitted was it a genuine Bosch MAF ?

Landyboy of birdflock · Nov 26, 2019

Hi Arctic2 no I don't have a synergy fitted and I have cleaned out the egr, but not too sure about the map sensor I think I did when I took the manifold off. Both the original one and the second hand maf had bosch on them thanks

Nodge68 · Nov 26, 2019

You can't use a Pierburg MAF without the Synergy 2 fitted, as it's specification isn't suitable. If the new Bosch MAF you fitted cost less than £100, then it's very likely that it's a fake, and not anywhere like as good as the genuine Bosch MAF. Avoid any MAF that is too good to be true, as it is too good to be true.
Only genuine Bosch MAFs are suitable.

Landyboy of birdflock · Nov 26, 2019

Okay nodge68 I have not fitted a new bosch maf, just the one that was already in it, and a used bosch maf off eBay

Nodge68 · Nov 26, 2019

Landyboy of birdflock said:
Okay nodge68 I have not fitted a new bosch maf, just the one that was already in it, and a used bosch maf off eBay

Ah. That could be the problem. A MAF has only a certain working life, and it's output starts to degrade the moment it's first used. So a second hand MAF is likely to be as bad as the original, or worse. Unfortunately second hand MAFs are worthless, as they all degrade over time. The only way to prove the MAF is to fit a genuine Bosch replacement. There is just the sensing element available, from another BMW car (I forget which) but it's about £50 cheaper than the complete Freelander MAF.

Arctic2 · Nov 27, 2019

Nodge68 said:
Ah. That could be the problem. A MAF has only a certain working life, and it's output starts to degrade the moment it's first used. So a second hand MAF is likely to be as bad as the original, or worse. Unfortunately second hand MAFs are worthless, as they all degrade over time. The only way to prove the MAF is to fit a genuine Bosch replacement. There is just the sensing element available, from another BMW car (I forget which) but it's about £50 cheaper than the complete Freelander MAF.

Hi John.
These have been used to some good success from the BMW but you only use the element remembering once the security tag as been broken to take out the sensor the warranty is void, so that must be taken into account. you are looking for this inside. ( F 00C 2G2 229)

1

as opposed to this which is blank.

2

I/we have tried quite a few after market MAF in the R40 forum one worked for about 12 months that we know of but the owner did not report back after that, I still have one in the cupboard but am waiting to find a member to fit it to his/her car for a long period of time and report back on a monthly basis, hopefully we have a member early in January to test that out for us.

3

Original Bosch MAF will also have an hologram on the box and a green O-ring round the sensor.

4

BMW may use only the insert
https://www.ebay.co.uk/itm/381351136629?ul_noapp=true

Nodge68 · Nov 27, 2019

Arctic2 said:
I/we have tried quite a few after market MAF in the R40 forum one worked for about 12 months that we know of but the owner did not report back after that

I used a cheap Ebay MAF for a while, but it quickly started causing issues with slow starting and sluggish low end response, so I put the original Bosch back in. It's still not working correctly, but the old Bosch is better than a few month old Ebay one.

Arctic2 said:
These have been used to some good success from the BMW but you only use the element remembering once the security tag as been broken to take out the sensor the warranty is void, so that must be taken into account.

Isn't just the sensing element available? from a BMW M5 IIRC. I'm sure the sensor numbers are the same, which would make more sense, although it probably won't work perfectly, as the sensor is likely calibrated to it's housing.

Arctic2 · Nov 27, 2019

Hi John.
I don't think the sensor is calibrated to it housing other wise the BMW Bosch one would not work as it does in the M40 housing when we have removed it from the BMW housing. Its those crucial number inside the sensor that needs to be followed. ( F 00C 2G2 229)

Nodge68 · Nov 27, 2019

Arctic2 said:
Hi John.
I don't think the sensor is calibrated to it housing other wise the BMW Bosch one would not work as it does in the M40 housing when we have removed it from the BMW housing. Its those crucial number inside the sensor that needs to be followed. ( F 00C 2G2 229)

I'm assuming that on the M40 jusj the sensor element is need for MAF replacement?

Arctic2 · Nov 27, 2019

Nodge68 said:
I'm assuming that on the M40 jusj the sensor element is need for MAF replacement?

Hi John.
On the R40 you can either replace just the sensor but if you purchased and genuine Bosch MAF with the housing it's best to fit it as an whole unit, otherwise the warranty would be void, also always replace the air filter at the same time. quite a few Rover 75 members have modified the air filter cover so it does not have to be removed if you were only going to change the MAF insert.

Nodge68 · Nov 27, 2019

Arctic2 said:
On the R40 you can either replace just the sensor but if you purchased and genuine Bosch MAF with the housing it's best to fit it as an whole unit, otherwise the warranty would be void,

I understand now. I thought I'd seen just the sensor available from Bosch, but could be wrong.

Arctic2 said:
quite a few Rover 75 members have modified the air filter cover so it does not have to be removed if you were only going to change the MAF insert.

That's a sensible mod, considering how awkward the rear filter housing bolts are to access.

Arctic2 · Nov 27, 2019

What FL1 owners need to look for is this below.

1

I always carry at least two in spec genuine Bosch MAF even though they are used ones they are checked on the T4 to be in spec.

2

Both have the ( F 00C 2G2 229) code on the insert.

3

Also the same hot wire

4

This is the after market MAF that we found to work for at least 12 months cost was £30 if I remember right, it was just a shame the owner did not come back to us after that period, I will try and chase it up later if I can.

5

6

The after market MAF was tried on a R40 diesel recently and it went right into the bin completely useless so steer clear at all costs.

mbrokof · Sep 11, 2022

Thanks @Arctic2 for the pictures and the explanaion. I had mine changed back to the old/original(?) one maybe two month' ago to check about the poor fuel con. It went further down to 11.5l. Measuring with pscan showed the air expected then mostly was higher than what came in. Since unplugging the old one fuel went down to 8l last week and 8.99 this week urban and the measurements were almost double on what came in, to what was expected therefore think will throw the old one to the bin. The 'new' has 4 years on now and gave similar values, will probably have to get a new one again. Both look like the pictures you've added. Not sure why the fuel con went down unplugged, but will measure again thinking to keep it unplugged. The fuel rail harness is due for change, will see if it'll help somewhat as well. Thanks again.

Arctic2 · Sep 12, 2022

Always add a new air filter if you changed out a MAF.

It's a good idea to clean the MAP sensor just wipe it over with a rag with some carb cleaner on it, note i said (MAP) not (MAF) anything touching the hot wire on a MAF will destroy it.

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