Fuel Consumption???

[E39 Ian]

My E39 540i Steptronic seems a little heavy on the juice..... I average about 15L/100km :bawling:

My daily commute is 120km through varied roads mostly highway which I cruise at 90km/h. Fuel consumption dial shows about 7L/100km.

Do I start looking a air flow meters, etc

However, no codes.

????????????

Would be happy at 12.9L/100km :thumbsup:

 

[rick540]

Possibly O2 sensors.....

I do the same mileage, same speeds and I use max 11-12 L/100Km

If your car has the Lucas injectors, change them for Bosch and save fuel

 

[clutchplate]

jislike, thats abit heavy
from jhb to PE I do like 8.5-9.5L per 100km, depending on how many trucks/cars I need to overtake

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in the city its bad tho .. but only because I'm an enthusiastic driver I think. could be better

 

[E39 Ian]

What do you recommend I try???

 

[rick540]

No codes.....

If the car still has the catalytic converter it could be blocked.

Clutchy is right, on the highway you should be getting anything from 7.5 -9.5 at 120Kmh on a flat road.

Just went and checked mine 10.5 L/100Km mixed open/city driving combined. One thing about the E39 540i with the M62 is unbeleivably good fuel consumption for such a big engine.

 

[E39 Ian]

Ok, how do I check if my catalytic converter is blocked?

How do I test if my oxygen sensors need replacement?

 

[clutchplate]

I have a better idea just remove your catalytic converters. all 4 of them
it makes it sound quite nice too

just take it to an exhaust shop, get them to replace the 4 cats with straight pipe.. and for the 2 rear O2 sensors, they must just make a little 2.5cm tube and mount the sensors into that.

simple as that

 

[rick540]

Oh yes, forgot to mention my cats are long gone, straight pipes and yes it does sound much nicer.

 

[E39 Ian]

On the odd occasion I do throw down the throttle I notice a large black cloud of smoke from the exhaust, running too rich, is that cats, o2 sensors and AFM all going?

 

[veridico]

I am averaging about 14.5 l/100km combined city and highway driving. If just city driving I get about 18l/100km. But Im not using a 540i.

 

[E39 Ian]

City driving will always be rough, however the 540i is a very special V8 from all accounts and has been designed to light on fuel. Another interesting thing is in all the road tests I can find on the net the steptronic (auto) is lighter on fuel than the manual version.

Just pulled a spark plug, see below:

<a href="http://s927.photobucket.com/albums/ad118/iandickie/?action=view&current=Photo-0032.jpg" target="_blank"><img src="http://i927.photobucket.com/albums/ad118/iandickie/th_Photo-0032.jpg" border="0" alt="18/04/2010 spark plug 1" ></a>

<a href="http://s927.photobucket.com/albums/ad118/iandickie/?action=view&current=Photo-0031.jpg" target="_blank"><img src="http://i927.photobucket.com/albums/ad118/iandickie/th_Photo-0031.jpg" border="0" alt="18/04/2010 spark plug 2" ></a>

Pics a bit unclear, the black is not oil but carbon build up of sorts, time for a change?

On Monday I going to an exhaust shop and have them cats removed! Looking forward to a sweeter sound from that V8 puppy!!

 

[E39 Ian]

Got down and dirty this afternoon, jacked up the car and saw the cats have already been removed, replaced with straight pipes!!

 

[clutchplate]

lol, no ways ? serious ?

you should not be seeing black smoke .. I drive the living CRAAAPPPP out of my car and it never smokes nothing :/

you could be having bad ignition.. I would suggest, getting injectors cleaned, and maybe new spark plugs
you're supposed to be using Bosch Platinum quad tip plugs btw .. they are abit more expensive, but they last ALLOT longer, and they are really good for ignition..

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trying to think .. but I'm not sure what else it could be..

 

[rick540]

Starting to think your MAF may be faulty

 

[SonGoKu619]

I know the threads old but hey..if it helps someone out there
I recently bought a 2001 540i, in town it was sitting between 18-24l/100km...quite scary actually...turns out it was one of the o2 sensors...Got it replaced and I'm averaging at around 11 l/100km

Now I can use the friggin kickdown