M4.4 Remapping.......

[ExternalError]

I don`t understand the figures either ....but looking at it logically which this may be the reason for the wrong or expected figures!........

The pic. of the 850R MAF the sensor part which reads the volume of air is in the centre of the MAF which it has to be to read the volume correctly also the design of the sensor with it`s thicker holder would of been calculated into the equation as it will effect the volume of air going past.

The pic. of the BMW MAF holder with the Volvo sensor in, the sensor is not in the centre of the holder so therefore you won`t get a proper reading of volume!

Also if you compare the Youtube pic. of the BMW MAF holder with it`s own sensor you will see although the pic. is on an angle the sensor is in the centre of the holder and is extremely thin to avoid any loss of volume of air going past and also will read the volume accurately.

I think the reason it is lean is because the 850R sensor is off centre in the BMW holder and so it is only capable of reading less but more air is going past due to it`s diameter.


Can you not use the BMW sensor or are the electrical ohms etc different or if you have a spare 850 sensor try modifying to go deeper into the holder to be central and also trim some plastic off it?

Good Luck

......................................

Could it have something to do with forced air hitting the sides of the MAF and causing pockets of turbulance which is why sensor is normally located at the centre. Not really sure but it seems to make sense in my head at least

[960kg]

I understand where you are coming from with the 850 sensor not being in the middle of the housing. The formula that I`m using with the maf editor software take in to account that the 850 sensor is not in the middle of the housing.

When I moved the sensor even more away from the centre of the housing my kg/hr readings where closer to the values in the maf editor software.

But that would make sense Rob as the more off centre the sensor is the more correct the MAF editor software readings are because as you say it allows for it!

Could it have something to do with forced air hitting the sides of the MAF and causing pockets of turbulance which is why sensor is normally located at the centre. Not really sure but it seems to make sense in my head at least

I don`t know but surely the larger BMW MAF is designed to work with it`s own more slender sensor in it`s centre......so really the nearer to the same shape as the original would be best, which is why i just suggested playing with the 850 sensor to allow it to get nearer the centre and also trim some plastic from it to make it more slender and as you say it would minimize turbulence of the measured air!

One thing seems definite ......the sensor is not accurately measuring the volume of air going past as the mix is lean!

[jamesy12345]

...
The scaling for the 3.25" maf over the standard maf is 1.94 using the maf editor I`ve got. My one and only O2 sensor is brand new

The scaling factor I mentioned was from here, page 10

http://www.paerl.it/volvo/Volvo%20Motronic%204.4.pdf

[Avinitlarge]

But that would make sense Rob as the more off centre the sensor is the more correct the MAF editor software readings are because as you say it allows for it!





I don`t know but surely the larger BMW MAF is designed to work with it`s own more slender sensor in it`s centre......so really the nearer to the same shape as the original would be best, which is why i just suggested playing with the 850 sensor to allow it to get nearer the centre and also trim some plastic from it to make it more slender and as you say it would minimize turbulence of the measured air!

One thing seems definite ......the sensor is not accurately measuring the volume of air going past as the mix is lean!

The BMW sensor is exactly the same as the Volvo one, the only difference is the plug. There are a number of people using this maf and table with no problems. Rob has a very odd issue. I would like him to get to the bottom of this, he has spent a lot of time on it. I can't see it, possible faulty ECU? I suppose its worth trying another.

[oblark]

The BMW sensor is exactly the same as the Volvo one, the only difference is the plug. There are a number of people using this maf and table with no problems. Rob has a very odd issue. I would like him to get to the bottom of this, he has spent a lot of time on it. I can't see it, possible faulty ECU? I suppose its worth trying another.

I`ve sent my bin file to Maarten who is going to check it in HxD, I hope to god it`s not a ecu problem but I`m on the look out for another one to do the same mod that you`ve done

[oblark]

The maf upper & lower tables didn`t match, thats why the logged values didn`t match the values in the maf table.

Thats that problem sorted on to the next, my LTFT_PL

My LTFT_PL is @+29.69 which is way to high, I`ve tried all different values but with no joy.

I know I was adding to much fuel as the car back fired everytime I changed gear.

Will get they in the end

[Jamest5r]

The maf upper & lower tables didn`t match, thats why the logged values didn`t match the values in the maf table.

Thats that problem sorted on to the next, my LTFT_PL

My LTFT_PL is @+29.69 which is way to high, I`ve tried all different values but with no joy.

I know I was adding to much fuel as the car back fired everytime I changed gear.

Will get they in the end

Over run on.lift.off is good I say keep it, do you get flames?

[oblark]

After going through a load of data logging, text files and xld files I thing I've found the problem.

Now I dont want to tell how I've come to this conclusion as it is complicated and it will go straight over your heads

but I need a new fuel filter.

[oblark]

Well I`ve changed the fuel filter and guess what still the same, So I`ve done some testing with different injectors/maf`s. The idea is to get the LTFT_PL to be as close to zero as posible on idle and while driving.

Whites with 3.25 maf @ idle



Whites with 3.25 maf driving



Whites with stock maf @ idle



Whites with stock maf driving



So the problem looks like it`s the 3.25 maf/maf table. I`m going to send the white/stock maf bin file to Piet who is goin to convert it to run the 3.25 maf as something is wierd is going on with my maf table convertor software.

[Dangerous Dave]

Yep, seems that way.

Hopefully Piet can get the right values for you.

[M-R-P]

Still want the squirters checked Rob?

[theflyingbrick]

well at least you found whats bugging it up,good news

[oblark]

Still want the squirters checked Rob?

I`m holding fire on them at the moment, I`ll see what comes back about the maf table

[oblark]

On Piet`s recomemdation I`ve checked the sensor too housing fit.

Sorry for the picture quality as they where taken on my phone.

I discovered that the 850 (right) sensors o ring is 6mm from the flange and the BMW (left) sensors o ring is 10mm from the flange.



Also the BMW maf housing has a 6mm deep chamfer whilst the volvo one only has a 2mm chamfer.

BMW maf housing.



Volvo maf housing.



So the o ring on the 850 sensor is not sealing againt the BMW housing as it sits where the chamfer is, to overcome this little problem I`ll get a thicker o ring tomorrow from work.

Then I`ll refit the maf with Piet`s bin file.

[Dangerous Dave]

Hmm, so it may be leaking then

[oblark]

Hmm, so it may be leaking then

It looks like it could of been, but only slightly.

[theflyingbrick]

slightly would be enough to cause grief on a standard tune so i reckon itll cause havoc on yours!!

[oblark]

The o ring on the 850 sensor is 3mm, so I`ve fitted a 4mm and its sealed the sensor to the housing.



The first picture is the 850 o ring and sensor, the second picture is the with the 4mm o ring, it pulled in nicely when the screws where done up.





I`ll go for a drive later on once the rush hour traffic has died down and report back

[oblark]

Loaded the bin file Piet checked for me and result one happy bunny

Here two screenshots first is at idle and the second one is driving.

[theflyingbrick]

wow thats a big difference!! just a little leak huh? glad you sorted it mate