healeyneil

Fuel consumption 528i

17 posts in this topic

Hi all.  My fuel consumption is currently averaging about 22.6 mpg according to the computer. It's an auto, I replaced the crank sensor with a BMW one, just done the front O2 sensors. It's had plugs and filter changed. It's not driven hard, cos it's my waftomatic. I'm sure it was getting about 26 before the CPS started to go. 

oh also cleaned the MAF twice. I was offered a good Bosch one to try, but the connection is different to the original Siemens one. Can't see any split hoses or the like, and it runs smoothly.

Any ideas/ comments please ?

neil

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Tyre pressures, wheel bearings, brakes dragging.

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That was quick ! Tyres just changed from winters to summers and checked, and it rolls freely so no issues there, but thanks anyway

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Ive seen an increase in mpg by +7 after changeing all my worn rear suspension ive a feeling the rose bushes were the main cause as rear wheels not running true

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Wow ! Funny enough Ive just had the subframe bushes done, and one rose bush will get done soon ( other was done last year )

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I noticed you said winter to summer tyres, that could account for 1 or 2mpg

Edited by 530d titansport

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Unfortunately the two didn't happen at the same time. The problem probably started around Christmas time when the CPS started to fail but that has been resolved. I should add that ne fault codes are being logged.

its just a bit annoying!

now if I had lpg fitted I probably wouldn't mind !

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I'm getting 31 on an hours commute including motorway and city, and that's on a 275,000 mile engine. You should be getting more!

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Ouch ! To be fair to the car, Im mostly doing short journeys, but it is getting to warm up at least. I'll try to borrow another MAF and try that

Neil

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Reset the trip and take for a drive down to Greenock on the M8.  Its the only bit of the motorway network near you that doesn't have cones on it and you can legally do 70mph.  If the car gets good mpg on this run then there is probably nothing wrong and its just the short journeys that is killing your mpg.

 

I do short journeys and get 26 mpg, the E60 was 22 mpg.  On longer motorway runs this would improve substantially.

 

Also get your 'box serviced by Mackies Transmissions at Tollcross, that should help too.

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Thank you 5351AR, I owe you one. Instead of Greenock, I drove across to Dalgety Bay, for reasons I will shortly explain. I reset the meter and set off. Just as I reached the Kincardine Bridge the reading hit 40 mpg ! Clear road and cruising at 70. On the return journey I hit the usual M8/M77 gridlock - 25 minutes for 5 miles - but my average for the trip, about 90 miles was 32.8 mpg ! Obviously I need to get out more! So theres nothing wrong with the car, which makes me happy :D The car will be booked into Mackies very soon, I just wanted to sort the  apparent fuel consumption problem first.

The trip to Dalgety Bay ? I bought a '99 528i manual touring for breaking. I need some bits for mine, and the engine/box etc will go to some 3series speeder. Ive just upgraded my membership here, so I'll be posting on the for sale section fairly soon

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Short trips kill the mpg, especially in an auto. Mine used to do about 18mpg in Bristol traffic, but average over 30 on a longer trip.

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Yup

 

Heading to training on a B road and through my local village, MPG in my 530i is around 18-22mpg... As soon as I hit the section of bypass I drive down to get onto the M6 and then onto the M6, MPG will be around 34-38!

 

Short journeys and slow roads are a bugger for fuel consumption, more so in a fuel guzzling auto like our BMWs! ;) 

Machinehead likes this

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Don't forget the mpg reading will over read by 5% to 10%. If you've high level obc you can correct it, not sure how on low versions.

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Thanks for all the answers. I can only assume my journey type had changed a bit. Fridays trip proved there's not much wrong with it. 

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I've owned a 525i Sport and now a 530i Sport and the fuel consumption has been identical on both. Average of 22mpg mixed driving with 90% of it motorway miles.

 

I'm not too worried as I don't pay for fuel. ^_^

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My 523 Auto touring was pretty poor around town. High teens I think. Got 31 on a long run just before the cat shat itself so suspect it would have done better thereafter. Didn't keep it long enough to find out.

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