E92 330i M Sport Auto MPG Issue (N52)
Discussion
Hello all,
I've avoided writing this post for a while as I can foresee the answers and quite rightly the answers will be "could be a lot of things". That being said I'll hold out hope that maybe someone has had a similar problem that they've fixed or at least a nudge in the right direction.
Recently purchased a 330i auto with 112k and the N52 engine. I love the car, it's superb. I am however as eluded to in the title getting 20.9mpg or there abouts regardless of how I drive it, I can re-set the trip and travel 50 miles on a motorway @ 65 and see mid 20's; maybe. Breathe on the throttle and I'm down to 20. Around town in stop start = 20mpg
The car is in very good condition and has no hesitation or other running issues, it's super smooth so no obvious plug/coil issues and no smell of petrol (it's not leaking out anywhere)
I've recently taken the car to Redish Motorsport for a PPI and all came back fine. I was hoping that a code may be stored that pointed toward say a dodgy coil etc but nothing, nothing noting anything that would cause such bad mpg. One thing they did note was that the golf tee mod had been done. I removed this and on the way home from Bristol I actually saw 31mpg on the motorway, I was elated for a few hours as I thought it had miraculously fixed itself. Then over the next couple of days I saw the figure slowly creep back down to 20 and it's stayed there.
Where do I go next? I don't want to start throwing £££ at the fuelling/ignition system replacing everything under the sun in the hope that something I change is causing the issue. As I said I know there's no magic answer but it's spoiling the enjoyment of the car as I'm fixated on (unsuccessfully) raising the mpg figure and getting dejected when it won't budge from 20.
My mates e92 m3 gets 26 hard driving and 30+ on a cruise for goodness sake.
TLDR - fuel economy is crap, no obvious issues, advice please.
I've avoided writing this post for a while as I can foresee the answers and quite rightly the answers will be "could be a lot of things". That being said I'll hold out hope that maybe someone has had a similar problem that they've fixed or at least a nudge in the right direction.
Recently purchased a 330i auto with 112k and the N52 engine. I love the car, it's superb. I am however as eluded to in the title getting 20.9mpg or there abouts regardless of how I drive it, I can re-set the trip and travel 50 miles on a motorway @ 65 and see mid 20's; maybe. Breathe on the throttle and I'm down to 20. Around town in stop start = 20mpg
The car is in very good condition and has no hesitation or other running issues, it's super smooth so no obvious plug/coil issues and no smell of petrol (it's not leaking out anywhere)
I've recently taken the car to Redish Motorsport for a PPI and all came back fine. I was hoping that a code may be stored that pointed toward say a dodgy coil etc but nothing, nothing noting anything that would cause such bad mpg. One thing they did note was that the golf tee mod had been done. I removed this and on the way home from Bristol I actually saw 31mpg on the motorway, I was elated for a few hours as I thought it had miraculously fixed itself. Then over the next couple of days I saw the figure slowly creep back down to 20 and it's stayed there.
Where do I go next? I don't want to start throwing £££ at the fuelling/ignition system replacing everything under the sun in the hope that something I change is causing the issue. As I said I know there's no magic answer but it's spoiling the enjoyment of the car as I'm fixated on (unsuccessfully) raising the mpg figure and getting dejected when it won't budge from 20.
My mates e92 m3 gets 26 hard driving and 30+ on a cruise for goodness sake.
TLDR - fuel economy is crap, no obvious issues, advice please.
It's a very good point Robb and call me crazy but I have not as yet. Having raised the issue with the boys over the last few days they've recommended the same, take the issue of the computer being wrong out of the equation, although the rate it goes through fuel it certainly feels like 20mpg.
I'll be doing this next before I start spending money but I haven't needed to use the car this week and I still have half a tank. Although I'm sure in about 80 miles I'll need to refuel. I'll mechanically calculate it then. I have a bottle of Forte injector cleaner in there at the moment (£16!) although I don't think it will do much.
I'll be doing this next before I start spending money but I haven't needed to use the car this week and I still have half a tank. Although I'm sure in about 80 miles I'll need to refuel. I'll mechanically calculate it then. I have a bottle of Forte injector cleaner in there at the moment (£16!) although I don't think it will do much.
aquarianone said:
What sort of fuel are you using..?
For what it's worth, my Zed has the same engine...and easily gets 28+ on a regular drive and 35+ on long distance.
When I had a similar drop in economy (down to low 20's)...a couple of things helped to fix it. one was a dodgy coil pack (they all been changed around 6 months prev) and the second was changing the battery (looks like it was still on the original).
Always Super from Sainsburys/Tesco predominantly. For what it's worth, my Zed has the same engine...and easily gets 28+ on a regular drive and 35+ on long distance.
When I had a similar drop in economy (down to low 20's)...a couple of things helped to fix it. one was a dodgy coil pack (they all been changed around 6 months prev) and the second was changing the battery (looks like it was still on the original).
I'd be the happiest man on earth with those figures bud. Hm interesting about the battery, wonder if that was coincidental or contributed, strange to think that could have any effect but who knows with 'modern' cars.
You know that's my next step - coils. I can replace all 6 for lets say £200 max (ECP) and for the outlay I'm thinking it's worth the money. I've read quite a few threads that have said similar things re the coil packs. I'm more than happy to put some money into her as I really love the car. I'll take a look a the battery as I know they don't like low voltage so may replace as it's winter anyway if it's past its best.
Cheers for the info.
I really hope replacing the coils fixes it.
Cheers for the replies all. In chronological order
Thermostat - yes has been mentioned also, I'll have a look at the hidden menus.
The m3 MPG - highly anecdotal I realise, just going off what he told me but did raise an eyebrow when he mentioned those very frugal numbers.
Running 19" style 225s with 35 all round. On an unrelated note I've had 3 punctures since owning the car, not a fan of 19's for puncture resistance! Think I'm just going through an unlucky spell
DISA flaps - hmm first I've heard of them but if the coil packs don't fix it I'll look into that next cheers bud.
metric vs gallons, would be surprised if it was that but will certainly check.
again laingy - agree, I'll see him tomorrow and call chinny reckon on him
I'll keep this updated and hopefully a resolution when I sort it so there's some closure
Thermostat - yes has been mentioned also, I'll have a look at the hidden menus.
The m3 MPG - highly anecdotal I realise, just going off what he told me but did raise an eyebrow when he mentioned those very frugal numbers.
Running 19" style 225s with 35 all round. On an unrelated note I've had 3 punctures since owning the car, not a fan of 19's for puncture resistance! Think I'm just going through an unlucky spell
DISA flaps - hmm first I've heard of them but if the coil packs don't fix it I'll look into that next cheers bud.
metric vs gallons, would be surprised if it was that but will certainly check.
again laingy - agree, I'll see him tomorrow and call chinny reckon on him
I'll keep this updated and hopefully a resolution when I sort it so there's some closure
It did have a water pump just before I bought it, maybe the thermostat wasn't changed and could be a good shout, I'll need to find the stats for the water temp also. I'd like to take it out tonight but will have to wait until the weekend to hopefully get this tyre repaired.
I'm hovering over the buy now for 6 coil packs from ECP so will no doubt pick those up soon. Delphi or Bosch though.
And a battery is £100 after discount yikes. Will only replace that if actually necessary, will see how it looks on the weekend too.
I'm hovering over the buy now for 6 coil packs from ECP so will no doubt pick those up soon. Delphi or Bosch though.
And a battery is £100 after discount yikes. Will only replace that if actually necessary, will see how it looks on the weekend too.
jeez these new cars. This is why I like my 27 year old Rover 216 GTI! Would that simply give an incorrect trip reading or actually effect consumption? The former I'm guessing. Something else I'll check cheers for the info. 
Gone ahead an ordered 6 oe Delphi coils, will see if they have any effect.
Was talking last night and it was suggested to eliminate/point the finger at the MAF. Took the car out with the MAF disconnected, the car applies a 'base map' if the MAF isn't readable as I understand it. With the car up to temp I did some bypass driving, mix of steady speed 65 mph and roundabouts to break it up. With the engine warm and the trip zero'd I saw 25.6mpg. This isn't motorway driving and has a hill involved a quite a few roundabouts etc so this sounds about right I'd say. Plugged the MAF back in after about 20 mins and saw 27.4mpg. So think the MAF can be ruled out also. Weird thing was the disconnection didn't throw up an error which I was expecting. Maybe it stored it in the shadow codes. Decent figures though but will see what the coils do when they arrive.
Was talking last night and it was suggested to eliminate/point the finger at the MAF. Took the car out with the MAF disconnected, the car applies a 'base map' if the MAF isn't readable as I understand it. With the car up to temp I did some bypass driving, mix of steady speed 65 mph and roundabouts to break it up. With the engine warm and the trip zero'd I saw 25.6mpg. This isn't motorway driving and has a hill involved a quite a few roundabouts etc so this sounds about right I'd say. Plugged the MAF back in after about 20 mins and saw 27.4mpg. So think the MAF can be ruled out also. Weird thing was the disconnection didn't throw up an error which I was expecting. Maybe it stored it in the shadow codes. Decent figures though but will see what the coils do when they arrive.
Well an update. Now the weather has warmed up and I'm not using the car for 4 mile trips where it doesn't even think of getting warm I've seen 32.8mpg on a run! Nothing has physically changed, the coils are still in the box but @ 32.8 on the motorway dropping to 31.2 when going through town in stop start traffic I'm thinking twice about even fitting them. Have to remember there are no fault codes being thrown so no confirmation that there's anything wrong with the current coil packs.
I'm sure it can get it back down into the mid 20's if I really want to but I'm more than happy with 30+ on a run.
Can't argue with success..
I'm sure it can get it back down into the mid 20's if I really want to but I'm more than happy with 30+ on a run.
Can't argue with success..
I think I may have actually found the issue this evening. Driving to and back from Brecon for an evening out I had an intermittent noise/vibration that was speed dependent. Did it twice before I decided to pull over and investigate; felt like mud/snow had got lodged in the wheel and was throwing the balance out. Got out to inspect the offside rear and could feel the heat coming from the wheel, sticking caliper! The disc wasn't red but was hugely more hot than the other 3 discs so I believe this could well be my issue. It definitely won't have been doing mpg any favours.
On my recent inspection Redish noted the offside rear caliper dust boot was missing and the piston was corroded, no brainer.
Caliper on order and will hopefully be fitted next week.
On my recent inspection Redish noted the offside rear caliper dust boot was missing and the piston was corroded, no brainer.
Caliper on order and will hopefully be fitted next week.
More of an update if not a cast iron answer if anyone else is researching the same issue.
Since renewing the calliper and changing the fluid (incidental) I haven't done that many miles. Another issue recently was replacing the battery. It died 2 weeks ago coinciding with the replacement of the calliper. Since replacing I've done one drive down the motorway and saw 30.0mpg and climbing when I reached my destination. So again; nothing definitive but having a weak battery could have been contributory factory also.
Short story - it seems to be sorted so if you're having the same MPG issue replace your rear off side calliper and buy a new battery!
Since renewing the calliper and changing the fluid (incidental) I haven't done that many miles. Another issue recently was replacing the battery. It died 2 weeks ago coinciding with the replacement of the calliper. Since replacing I've done one drive down the motorway and saw 30.0mpg and climbing when I reached my destination. So again; nothing definitive but having a weak battery could have been contributory factory also.
Short story - it seems to be sorted so if you're having the same MPG issue replace your rear off side calliper and buy a new battery!
Gassing Station | BMW General | Top of Page | What's New | My Stuff