E92 330i M Sport Auto MPG Issue (N52)
Discussion
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..
squareflops said:
Euro Car Parts, £188 I think for all 6. They're N52 specific, I recall the N53 items being quite a bit cheaper.
Recommended by a BMW tech to buy Delphi as that's what they use and should be current models. Apparently Bosch can be older units but that's just anecdotal.
Interesting. I've an n53 and I thought the coils were the same tbh. Will check out ECP cheers. And yes delphi is what bmw currently fit. They have the metal rather than plastic shielding.Recommended by a BMW tech to buy Delphi as that's what they use and should be current models. Apparently Bosch can be older units but that's just anecdotal.
squareflops said:
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..
4 mile trips will kill your mpg, moreso in cold weather. I have a 335i that is in tip top condition (barring a potential walnut blast) and get around 22mpg as it’s mainly used for trips to the station, nursery drop off etc OR long motorway trips. 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..
While the 6-speed auto is fine once in the higher gears, it’s still a slush box at slow speeds and so eats up both power and mpg. The 335i is also very torquey, so the 330i will be working harder at low revs.
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.
Cool, something certainly is at fault and that could be it!
My E90 330i Manual average 31mpg over it's life time, half urban (London). It would average about 30mpg at 90 leptons on the cruise. Always run on 95, as unlike the s54, I couldn't notice any difference in mpg or response on super.
At 70mph it would do high thirties. All indicated though, so probably a little optimistic.
Overall, about 3-4 mpg better than the MX5 I had before, with half the power!
My E90 330i Manual average 31mpg over it's life time, half urban (London). It would average about 30mpg at 90 leptons on the cruise. Always run on 95, as unlike the s54, I couldn't notice any difference in mpg or response on super.
At 70mph it would do high thirties. All indicated though, so probably a little optimistic.
Overall, about 3-4 mpg better than the MX5 I had before, with half the power!
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!
I don't think the battery was part of the issue!
My 325i (also N52 engine) was showing 35.3 mpg, then in January it needed a new battery. But when that is fitted the OBC resets the average mpg, so mine is now only showing 33.2 mpg (probably mostly due to colder weather).
I think the issue was your caliper, but at least it's now sorted!
My 325i (also N52 engine) was showing 35.3 mpg, then in January it needed a new battery. But when that is fitted the OBC resets the average mpg, so mine is now only showing 33.2 mpg (probably mostly due to colder weather).
I think the issue was your caliper, but at least it's now sorted!
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