E39 M5 Fuel Consumption

[ANiMOSiTY]

The car has CA Automotive software on it, and is ex Joburg. I live in Cape Town.

FWIW, the car does not have CA software on it. Before I sold it, I changed the software to an Xcede remap. My consumption improved massively after that.

Poked Mafs make a huge difference from what I remember with An1mosity's car.

It was my CPSes that were busted.
But yes, dirty MAFs had a detrimental effect on fuel consumption.
I was able to get away with cleaning mine only.

Eon, have you done the L/H MAF test that's mentioned on M5Board?
As far as I remember, Bio's car was always a little heavier on fuel than mine.. but it had the mods to go along with that.. Although I'm talking a difference of 0.5 to 1.5 l/100km at most, depending on the type of driving.

 

[JadielM]

Also try remapping the car. Your car's mapped for reef and you're at sea level.

You're also comparing a modified car's consumption to that of it's stock equivalent.

I'd try remapping the car/reloading the stock map

 

[E63AMG]

The car has CA Automotive software on it, and is ex Joburg. I live in Cape Town.

FWIW, the car does not have CA software on it. Before I sold it, I changed the software to an Xcede remap. My consumption improved massively after that.

Poked Mafs make a huge difference from what I remember with An1mosity's car.

It was my CPSes that were busted.

Ah, right! It's been quite a few years since we were fiddling with mafs in the basement parking and my memory is a bit fuzzy
These threads are making me quite nostalgic about my old M5...

 

[ANiMOSiTY]

The car has CA Automotive software on it, and is ex Joburg. I live in Cape Town.

FWIW, the car does not have CA software on it. Before I sold it, I changed the software to an Xcede remap. My consumption improved massively after that.

Poked Mafs make a huge difference from what I remember with An1mosity's car.

It was my CPSes that were busted.

Ah, right! It's been quite a few years since we were fiddling with mafs in the basement parking and my memory is a bit fuzzy
These threads are making me quite nostalgic about my old M5...

I know.. I miss mine

Sent from my SM-G900F using Tapatalk

 

[Eon]

The car has CA Automotive software on it, and is ex Joburg. I live in Cape Town.

FWIW, the car does not have CA software on it. Before I sold it, I changed the software to an Xcede remap. My consumption improved massively after that.

Poked Mafs make a huge difference from what I remember with An1mosity's car.

It was my CPSes that were busted.
But yes, dirty MAFs had a detrimental effect on fuel consumption.
I was able to get away with cleaning mine only.

Eon, have you done the L/H MAF test that's mentioned on M5Board?
As far as I remember, Bio's car was always a little heavier on fuel than mine.. but it had the mods to go along with that.. Although I'm talking a difference of 0.5 to 1.5 l/100km at most, depending on the type of driving.

What are CPSes?
I have tried cleaning the MAFs thoroughly with isopropyl (rubbing) alcohol but without success.
I've tried searching M5Board for that L/H test but didn't find many MAF specific topics relating to fuel consumption.

What I have done is I swopped mine with my collegue's E39 M5's MAFs and it seemed to behave normally over the 35-odd km that I borrowed them. The consumption has improved slightly (it should be even better with a coast tuned map) but more importantly, it had no misfires and stalling after hot start!

For now I have unplugged the MAFs and the car drives and behaves like normal, no perceived power loss or rough running. The only thing that is not normal is the over fuelling (ie. lots of backfiring, a small puff of black smoke on pullaway, outrageous fuel consumption, and a black speckled rear bumper).

The Xcede map was definitely for JHB altitude. Phone Sherwin and see what he'll do for you regarding a CTN map perhaps.

Do I just look up Xcede and ask for Sherwin? Seeing as the car had been mapped by them before, would he be generous enough to offer the map at reduced or no cost as an 'update' included in their after sales service?

 

[Ratslaaf]

Why not get the car back to stock firmware and work from there?

 

[Eon]

Why not get the car back to stock firmware and work from there?

That might not be a bad idea. Except for the car having no cats or cat foolers in place. How do you suggest I go about it?

 

[Ratslaaf]

It'll run just fine on a stock tune, it'll just throw a CEL light due to the post cat O2 sensors being missing. Once you happy that the car is better (or not) the O2 sensor errors can be masked out in software.

When last have you had codes read on this car?

 

[Andrew]

For your MAF you only need to replace the insert - If I recall the part number on the sensor is 00C2G2029. Only use genuine Bosch item.

They come out on loads of cars and should be around R1800 each

For the record my E39 M5 uses around 21l/100km around town and about 14.5 l/100km on the open road. This is driving without any consideration for fuel consumption. I suspect she is running a little rich though and plans are to replace primary O2 sensors and MAF's and possibly the CPS's

 

[Eon]

It'll run just fine on a stock tune, it'll just throw a CEL light due to the post cat O2 sensors being missing. Once you happy that the car is better (or not) the O2 sensor errors can be masked out in software.

When last have you had codes read on this car?

ChrisBrand last read the codes for me about a month ago.

I will have to replace the MAFs anyway.

The more I think of it, the more I like the sound of loading back the stock software.
Who can do this for me?

Then, once I am happy with the car running normally again, it will have to be tuned according to its hardware mods (branches, exhaust etc.) to make it fast again

 

[Ratslaaf]

I should be able to assist remotely. Send me a PM to discuss