High Fuel Consumption?

[Arma 134]

What kind of fuel consumption (litres per 100km) are e39 530i's generally supposed to be getting, because mine seems to always be higher than what most people say I should get with this car. To test I filled my tank up, and for the next couple weeks I drove as calm and softly as I can with no crazy acceleration etc. and I still never seem to get under 12L/100km. I used an app to keep track of my fuel usage by recording my odometer readings and how much I refuel to full tank each time and it has always stirred close to, if not over, 13L/100km and occasionally close to 14L/100km when I drove a bit more spiritedly. Here are some of my recent fuel ups:

8/06/2013 - Refuelled after travelling 309km - 12.94L/100km

31/05/2013 - Refuelled after travelling 322km - 13.87L/100km

26/05/2013 - Refuelled after travelling 92km - 12.87L/100km

25/05/2013 - Refuelled after travelling 469km - 14.02L/100km

18/05/2013 - Refuelled after travelling 325km - 14.93L/100km !

Those close to 14L or over 14L are when I drive a bit more spiritedly but only slightly. It is not even close to thrashing or anything - generally shifting at 3k-4k rpm. Those under 13L are when I drive calmly in 'D' with shifts at 2k-2.5k rpm.

Most people have been telling me fuel consumption should be better than this - should they? Or is there something that might be causing my fuel consumption to be higher than usual (MAF sensor, spark plugs etc. etc.) ? The only non stock part of the car I know is one of the mufflers (located near the centre of the car) has been taken out and straight pipes put in instead, and there are twin exhaust tips, opposed to the single stock one - not sure if this would effect it.

Edited June 11, 2013 by Arma

[M5V8 337]

get it scanned. Hopefully that should tell you something.

But from memory the ECU uses inputs from the MAF & 02 sensors to trim fuel maps. But anything from old spark plugs or crap fuel could affect.

But you are right. I regularly get 10l/100 in my M5 cruisin @ 100kph on the motorway, 14-15 on average when i hammer it and usually 600km out of a tank.

Edited June 11, 2013 by M5V8

[Arma 134]

get it scanned. Hopefully that should tell you something.

But from memory the ECU uses inputs from the MAF & 02 sensors to trim fuel maps. But anything from old spark plugs or crap fuel could affect.

But you are right. I regularly get 10l/100 in my M5 cruisin @ 100kph on the motorway, 14-15 on average when i hammer it and usually 600km out of a tank.

Have had it 'quick scanned' (not the one that lasts 20 minutes or something) less than a month ago and only fault was the exhaust cam sensor, which I replaced. Had no faults since. Ray did a quick scan at the CSL meet, no faults there either. I guess I should have a full diagnostic scan done (that covers everything) to be able to pick up on this?

You getting 10l/100 on your m5 - yeah something's got to be off with mine . Hope it's just spark plugs..

[Arma 134]

Come to think of it my 520i has been getting some pretty high fuel consumption as well...

[Ahmedsinc 414]

13/100 sounds fairly close for a nearly 2 tonne 12 year old car with a 3 litre I6 driven pleasantly. Big cars tend to have matching appetites.

Give it hotter plugs and a proper service & see if anything happens

[Allanw 1071]

You may find the thermostat is poked and it's not warming up correctly (the dash gauge won't reflect this is most situations - it shows normal from about 70-75C, upto 115C at least).

Our 525i manual gets 10.4 in our normal around town commute stuff (Kindy, library etc) and I can get 7.0 on a run (though usually more like 8L/100kms with the family and all the gear.

You can check the coolant temp (KTMP) on the secret OBC menu. An M54 powered E39 should be running in the 90's most of the time, generally mid to high 90's, but as low as high 80's if being driven hard.

You can Google how to do it, depends on whether you have high or low obc (text display or picture of a car under speedo)

[Jamex316 1]

I used to get under 12L/100km on my e39 530i, until I decided to try out the upper engine cleaner on the intake....oops...didn't think a cleaner could do so much, it probably decided to have a fit over it...not doing it again...

Now getting similar figures to you. But I've tried resetting the ecu just to let it remap things. Figures are improving now.

[Arma 134]

You may find the thermostat is poked and it's not warming up correctly (the dash gauge won't reflect this is most situations - it shows normal from about 70-75C, upto 115C at least).

Our 525i manual gets 10.4 in our normal around town commute stuff (Kindy, library etc) and I can get 7.0 on a run (though usually more like 8L/100kms with the family and all the gear.

You can check the coolant temp (KTMP) on the secret OBC menu. An M54 powered E39 should be running in the 90's most of the time, generally mid to high 90's, but as low as high 80's if being driven hard.

You can Google how to do it, depends on whether you have high or low obc (text display or picture of a car under speedo)

I have high obc and have yet to try to unlock it (scared of destroying something). Might have it scanned properly soon and have a look at the spark plugs (even though that's just one of many things that could be causing this..). I've noticed sometimes the temperature dial isn't always at the centre (12 oclock) but sometimes slightly less (around 11 oclock) - but I don't know if this is even related as this does not always happen (e.g. it stayed centred the whole way home this evening).

Note car has done about 98xxx km's now.

Edited June 11, 2013 by Arma

[jeffbebe 1559]

I asked all the same questions when I got my 528i. Turns out after a lot of analysis and a fair bit of expense, that nothing was wrong. They're just really thirsty if you do a lot of stop/start city driving. I'd be lucky to get 18L/100 around town as I was doing a lot of short 5-10 minute drives from cold starts. As soon as she was on the open road would get 7-8L/100.

Just got to go with it if you live in the city, I'm afraid. I only really use the 540i now as a weekender. Don't really need a daily anymore as work is 2mins walk from home and would rather not have to worry about fuel consumption because I want to enjoy my drives!!

[Tristan 338]

I asked all the same questions when I got my 528i. Turns out after a lot of analysis and a fair bit of expense, that nothing was wrong. They're just really thirsty if you do a lot of stop/start city driving. I'd be lucky to get 18L/100 around town as I was doing a lot of short 5-10 minute drives from cold starts. As soon as she was on the open road would get 7-8L/100.

Just got to go with it if you live in the city, I'm afraid. I only really use the 540i now as a weekender. Don't really need a daily anymore as work is 2mins walk from home and would rather not have to worry about fuel consumption because I want to enjoy my drives!!

When I had the car I was thinking the same thing, really high consumption.

After thinking about it a bit, I was always doing short drives to work/uni from cold so it chewed through the fuel.

[Arma 134]

I asked all the same questions when I got my 528i. Turns out after a lot of analysis and a fair bit of expense, that nothing was wrong. They're just really thirsty if you do a lot of stop/start city driving. I'd be lucky to get 18L/100 around town as I was doing a lot of short 5-10 minute drives from cold starts. As soon as she was on the open road would get 7-8L/100.

Just got to go with it if you live in the city, I'm afraid. I only really use the 540i now as a weekender. Don't really need a daily anymore as work is 2mins walk from home and would rather not have to worry about fuel consumption because I want to enjoy my drives!!

When I had the car I was thinking the same thing, really high consumption.

After thinking about it a bit, I was always doing short drives to work/uni from cold so it chewed through the fuel.

I drive from Flat Bush -> City for work and back everyday (about ~30km one way) and even on highway cruising I seemed to be getting 12+. No way have I ever gotten 7-8/100 on open road. Maybe it's just the way it is - moving to city soon anyway, so might get higher but gotta travel a shorter distance so would be spending less .

[jeffbebe 1559]

I drive from Flat Bush -> City for work and back everyday (about ~30km one way) and even on highway cruising I seemed to be getting 12+. No way have I ever gotten 7-8/100 on open road. Maybe it's just the way it is - moving to city soon anyway, so might get higher but gotta travel a shorter distance so would be spending less .

If your commute is stop/start and low speed (and low gears) it'll use a fair bit of fuel but highway cruising should be better than 12L/100 unless you're driving up hill the whole time!

Definitely worth checking some of things suggested above. Does it idle rough when cold? Quite a few folks reckon perished vanos seals can be responsible for poor consumption and other issues. I never got to them on my 528i but worked my way through all the cheaper stuff first - thermostat, vacuum hoses, injector seals, etc. Would have done Vanos too eventually if I'd kept the car and plan to do it on the 540i in the next couple of months as I need to replace valve cover gaskets soon anyway to fix an oil leak.

Hopefully the complete vanos overhaul and replacing all of the gaskets recommended on the Beisan website will give the engine a new lease of life. Not cheap to do but worth it IMO to give the car the best chance of doing another 200,000+ mms of trouble free motoring!

[Arma 134]

If your commute is stop/start and low speed (and low gears) it'll use a fair bit of fuel but highway cruising should be better than 12L/100 unless you're driving up hill the whole time!

Definitely worth checking some of things suggested above. Does it idle rough when cold? Quite a few folks reckon perished vanos seals can be responsible for poor consumption and other issues. I never got to them on my 528i but worked my way through all the cheaper stuff first - thermostat, vacuum hoses, injector seals, etc. Would have done Vanos too eventually if I'd kept the car and plan to do it on the 540i in the next couple of months as I need to replace valve cover gaskets soon anyway to fix an oil leak.

Hopefully the complete vanos overhaul and replacing all of the gaskets recommended on the Beisan website will give the engine a new lease of life. Not cheap to do but worth it IMO to give the car the best chance of doing another 200,000+ mms of trouble free motoring!

Nice , best keep that big engine happy!

I usually drive at 930 in the morning so theres almost no stop-start traffic from my place to the city (about 95% of the way I am doing 100 without having to stop) - so I should really be getting better than 12L/100km if others get so much less on open road, with thirstier engines. Not sure if this means anything but the temperature gauge on the dash takes quite a while to reach the 12 oclock position. I drove a whole 30km from my place to city and it stayed on or just before the first mark on the gauge (which is located at about 10 oclock). Once I drove around the city a bit, it finally reached 12oclock position. Maybe it's just the cold weather?

Edited June 11, 2013 by Arma

[jeffbebe 1559]

It should reach the centre position within 5 minutes. Could be a faulty thermostat. Worth checking the actual operating temp as Allan suggests. Try this - http://www.ideaphile.com/bmw/540-obc.html - test no.7 gives engine core temp.

[allan 295]

Even doing 30k trip you should be getting better fuel consumption than that mine did no worse than 735k to a tank of gas 95 oct and 750k on 98 open road running and not being nanny

From cold start up how long, distance wise does it take for the temp gauge to reach it's normal reading? The thermostat on my old 2001 530 had electrically connection to the DME and this failed so instead of operating temp being reached very quickly, less than 2k it took some time to reach operating temp replaced the thermostat and problem solved.

Have you checked the idle control valve these get sticky and can jam.

Vacuum lines/ air lines, I found two rubber plugs at the back of the inlet manifold one of these had gone hard and split open plus the take off from the main air intake has a plastic plug outlet for a couple of hoses check their just a thought.

Engine breathe tubing had one split down by the dip stick.

Just a few other items if not already mentioned

MAF on the way out, air filter, spark plugs, crap in the air box, inlet ducting.

[Arma 134]

Even doing 30k trip you should be getting better fuel consumption than that mine did no worse than 735k to a tank of gas 95 oct and 750k on 98 open road running and not being nanny

From cold start up how long, distance wise does it take for the temp gauge to reach it's normal reading? The thermostat on my old 2001 530 had electrically connection to the DME and this failed so instead of operating temp being reached very quickly, less than 2k it took some time to reach operating temp replaced the thermostat and problem solved.

Have you checked the idle control valve these get sticky and can jam.

Vacuum lines/ air lines, I found two rubber plugs at the back of the inlet manifold one of these had gone hard and split open plus the take off from the main air intake has a plastic plug outlet for a couple of hoses check their just a thought.

Engine breathe tubing had one split down by the dip stick.

Just a few other items if not already mentioned

MAF on the way out, air filter, spark plugs, crap in the air box, inlet ducting.

Thanks for the info. It took between 20 and 30km before the temp gauge was at normal reading (12 oclock). Probably should make a list and take it in to check the few possibilities out - haven't got the tools (nor the experience for some of the things) to DIY at home.

Edited June 12, 2013 by Arma

[Allanw 1071]

I've noticed sometimes the temperature dial isn't always at the centre (12 oclock) but sometimes slightly less (around 11 oclock)

If it ever drops down, or isn'tsolid at 12 after about 5 minutes, there is something wrong with the thermostat - Like I say - for it to read 11 oclock, it would only be running at about 60-70 degrees - it will richen the mixture at that point. It's a common E39 thing.

Scanning won't show anything, unless the thermostat electronics are poked (which is common too).

Check the OBC - you can't screw anything dramatic up - especially if you follow the instructions.

I'd be looking to replace the thermstat based on what you've said. They crap out one way or another pretty often anyway!

[Arma 134]

If it ever drops down, or isn'tsolid at 12 after about 5 minutes, there is something wrong with the thermostat - Like I say - for it to read 11 oclock, it would only be running at about 60-70 degrees - it will richen the mixture at that point. It's a common E39 thing.

Scanning won't show anything, unless the thermostat electronics are poked (which is common too).

Check the OBC - you can't screw anything dramatic up - especially if you follow the instructions.

I'd be looking to replace the thermstat based on what you've said. They crap out one way or another pretty often anyway!

Thanks. Will try monitor the secret OBC menu temperature values to see if it looks a bit off.

Can the thermostat in e39s be changed without removing the fan?

[SimJen 0]

I get 8l/100kms on my 330 on long journeys and around 14l/100km around town! But around town I have quite a heavy foot

[allan 295]

"Can the thermostat in e39s be changed without removing the fan?"

Any thing is possible but it could be difficult and painful on the hands removing the fan is not hard.All you need is a rubber mallet or hammer, 12" crescent if you don't have a 32mm spanner a quick smack and undo the nut. OH it's a left hand thread so you will have to try and tighten it to undo it. Then remove fan shroud all done makes life so much easier.

[Allanw 1071]

You can remove the fan, and drop it down inside the shroud, VERY carefully, and the shroud can stay on. It's a little fiddly, but slightly easier than removing the shroud.

When refitting the thermostat, I like to use a very little bit of neutral cure sealant and the rubber gasket, tighten it up, the leave it to set overnight, before filling and bleeding the system.

If you aren't confident to do it yourself, it's probably not expensive to have done - perhaps it could be done when you get the oil leak sorted??? or was that on the 520i???

[Arma 134]

You can remove the fan, and drop it down inside the shroud, VERY carefully, and the shroud can stay on. It's a little fiddly, but slightly easier than removing the shroud.

When refitting the thermostat, I like to use a very little bit of neutral cure sealant and the rubber gasket, tighten it up, the leave it to set overnight, before filling and bleeding the system.

If you aren't confident to do it yourself, it's probably not expensive to have done - perhaps it could be done when you get the oil leak sorted??? or was that on the 520i???

Ah cool thanks. Might just get it done somewhere to avoid mishandling something. The oil leaks are on the 520i - but haven't been driving that lately so didn't bother fixing the leaks yet, gotta get round to that at some point. Thermostats are like 60 USD on turner motorsport, hope they aren't too much more expensive here if I do end up needing a replacement.

[NZ BMW 368]

There is also a aux water/coolant pump which kicks in when it's cold to bring the car up to temp faster. Mine is buggered and it takes about 7 minutes to bring the car up to the 12 o'clock position on the temp gauge.

If you get someone to scan the car and they delve deeper into the system it will throw a code, Ray up at HellBM found that on mine. Unlike the V8 this pump is not a "must have" for the car so it does not cause any visible issues.

My car get's about 10km/L on the open road or better and around 7km/L around town so not so great. My average speed including the odd bit of motorway over the last few months has been 32km/h according to the computer...

[jeffbebe 1559]

Be happy... In the V8 I managed a thirsty 5.12km/L since the last fill. Admittedly, I have been very heavy footed but the $/fun ratio has been excellent!!

Have just ordered complete set of valve and timing gaskets + Beisan Systems vanos seals for an overhaul of the timing unit and valve boxes in the next couple of months.

The goal is to fix the rough idle when cold, hunt down and eradicate all oil and vacuum leaks while the engine's in bits, repaint rocker covers and hopefully improve performance and fuel consumption. Will be interesting to compare after the pre and post vanos procedure so I'll definitely report back when it's all done.

Just got to save up for the labour now as the vanos procedure is way beyond my limited skills. Ray reckoned around 10-15 hours of work to do the lot.

EDIT: Incidentally, picked up a new thermostat from Schiedmann at the same time as the gaskets for around NZ$85. Their shipping prices are competitive but can't tell you exactly how much as I bought a bunch of stuff at the same time (a lot cheaper than Turner though!).

Edited June 15, 2013 by jeffbebe

[beemn 50]

What kind of fuel consumption (litres per 100km) are e39 530i's generally supposed to be getting, because mine seems to always be higher than what most people say I should get with this car. To test I filled my tank up, and for the next couple weeks I drove as calm and softly as I can with no crazy acceleration etc. and I still never seem to get under 12L/100km. I used an app to keep track of my fuel usage by recording my odometer readings and how much I refuel to full tank each time and it has always stirred close to, if not over, 13L/100km and occasionally close to 14L/100km when I drove a bit more spiritedly. Here are some of my recent fuel ups:

8/06/2013 - Refuelled after travelling 309km - 12.94L/100km

31/05/2013 - Refuelled after travelling 322km - 13.87L/100km

26/05/2013 - Refuelled after travelling 92km - 12.87L/100km

25/05/2013 - Refuelled after travelling 469km - 14.02L/100km

18/05/2013 - Refuelled after travelling 325km - 14.93L/100km !

Those close to 14L or over 14L are when I drive a bit more spiritedly but only slightly. It is not even close to thrashing or anything - generally shifting at 3k-4k rpm. Those under 13L are when I drive calmly in 'D' with shifts at 2k-2.5k rpm.

Most people have been telling me fuel consumption should be better than this - should they? Or is there something that might be causing my fuel consumption to be higher than usual (MAF sensor, spark plugs etc. etc.) ? The only non stock part of the car I know is one of the mufflers (located near the centre of the car) has been taken out and straight pipes put in instead, and there are twin exhaust tips, opposed to the single stock one - not sure if this would effect it.

We had a nz new e39 530i sport and round town would be high 12's low 13's but thats driving from Westmere to Parnell to my wifes office, on a trip high 8's. our e39 540i sport (replaced the 530) would be around 15l/100 around town and about 10 or 11 on a trip but the X5 (replaced the 540) is 18.1 around town and as low as 11 on a trip but thats a 6 speed.....seems i have a habit of replacing cars with ones that are less fuel efficient...sweet

I dont think your car is too far off, as some one else has already mentioned its a heavy car despite having all alloy stuff under it

Edited June 15, 2013 by beemn