MPG Drop after full service

mr wilks · Post by **mr wilks** » Mon Oct 17, 2016 8:50 pm

More the better Chris , i never go over 12 months or 7k so whichever comes around first , doubt i would ever do 7k in a year with one car though

RickRob · Post by **RickRob** » Mon Oct 17, 2016 9:01 pm

Are you sure that it's not that your £54 is just buying you less petrol following recent price hikes due to the exchange rate?

Chris_D · Post by **Chris_D** » Mon Oct 17, 2016 9:11 pm

mr wilks wrote:More the better Chris , i never go over 12 months or 7k so whichever comes around first , doubt i would ever do 7k in a year with one car though

I only decided to do it so regularly as the car was my workhorse for getting me around Europe visiting clients in Poland, Germany and Switzerland. I used to take advantage of the derestricted sections of Autobahn in Germany especially and cruised effortlessly at 130-140mph back home to Holland. Hence, the thinking was longevity of the engine and regular oil changes as preventive maintenance.
The last compression check revealed a within-spec reading of factory-fresh on 5 of the 6 cylinders and the 6th not far behind. I might add that it was never revved hard and never saw the redline or limiter.
So I would certainly recommend regular oil changes to anyone even though not ultimately verifiable. Obviously motorway miles at high compression rates can only help but other dynamics will have an influence on how long any given engine will last.

flybobbie · Post by **flybobbie** » Mon Oct 17, 2016 9:42 pm

My mpg on the 23i has gone down a few miles.
Cooler air means more fuel being pumped in, more power, less mpg.
You don't get howt for nowt.
What we call density altitude in aviation.

goldbcfc · Post by **goldbcfc** » Tue Oct 18, 2016 5:25 pm

since when did an oil change cause bad mpg....lol

it most likely the fuel and air mixture if you have turbos then it more noticable

Doddsy · Post by **Doddsy** » Tue Oct 18, 2016 6:33 pm

mr wilks wrote:
Doddsy wrote:
mr wilks wrote: Personally I wouldn't run any car i had on 0w 30 ok for hitting the best MPG but not best for protection of the vital parts as miles increase
Hi Mr Wilks, I put Castrol edge FST long life 04 titanium 0W-30 in my 2.5si at 55k. Now at 60k what would you use? 5W-30?
Cheers
I would definitely be on to 5w 30 grade & my own preference is Millers so any of their fully synth range is top quality .
I would still change every 12 months or 7k though

http://www.ebay.co.uk/itm/MILLERS-EE-LO ... SwwpdW227w

Cheers! I'll take a look at millers then.

goldbcfc · Post by **goldbcfc** » Wed Oct 19, 2016 9:22 am

Probably have faulty maf or intake sensor why would your mpg drop so much. I work in trade seriuosly oil would not affect the mpg so much. Have you even checked your air intake box to see if after the service the tech reseated it properly soinds more like a vacuum leak not oil change. Remember young trainees do services its first thing dealers teach/ trust you to do. Reason i service my own and i work for a dealer so i know whos doing these jobs some 17yr

martins · Post by **martins** » Wed Oct 19, 2016 10:40 pm

I have a similar issue, also with a 35i, but my service wasn't recent. I've also had the engine light on with P0171 & P0174 running lean codes. These codes were cleared and they've not come back, but I'm still only getting 26MPG where I used to get >30.

I've read up that it could be a vacuum leak, MAP sensors or O2 sensors. Is there any way of me further diagnosing this, or is an expensive trip to the garage in order?

M.

benv6 · Post by **benv6** » Sun Oct 23, 2016 8:42 pm

Just to update you guys! everything was fine with the service as I am not the guy who would hand my keys and go away while my car is being worked on, my Indy is used to me getting involved when anything is being done on my cars.

I have changed the fuel from the standard unleaded to the SHELL V-POWER and now my MPG stands at 29mpg with some spirited driving in both central London and some motorway driving .... it is not too bad atm.

martins · Post by **martins** » Sat Oct 29, 2016 10:31 am

martins wrote:I have a similar issue, also with a 35i, but my service wasn't recent. I've also had the engine light on with P0171 & P0174 running lean codes. These codes were cleared and they've not come back, but I'm still only getting 26MPG where I used to get >30.

I've read up that it could be a vacuum leak, MAP sensors or O2 sensors. Is there any way of me further diagnosing this, or is an expensive trip to the garage in order?

M.

I've also tried using v-power, and apart from having a lighter wallet sadly my MPG still sucks at 26MPG. I'm tempted to replace one or both MAP sensors as I can't believe both O2 sensors would fail at once, unless anyone would be kind enough to offer some guidance on other diagnostics I could do to narrow this down a little? I'm not getting any other noticeable issues other than low MPG and a noticeable increase in soot lining the exhaust outlets.

M.

freemadw · Post by **freemadw** » Sat Oct 29, 2016 11:36 am

The soot would imply that it's running too rich. Does sound like you might have a problem with air filters or MAP/02 sensors.
I'm afraid I can't offer anything more constructive than that, I'm sure you've checked that there are no obvious hoses/cables disconnected.
Cheers, Dave

martins · Post by **martins** » Sat Oct 29, 2016 5:33 pm

freemadw wrote:The soot would imply that it's running too rich. Does sound like you might have a problem with air filters or MAP/02 sensors.
I'm afraid I can't offer anything more constructive than that, I'm sure you've checked that there are no obvious hoses/cables disconnected.
Cheers, Dave

I've done a quick check over and there isn't any obvious signs of disconnected hoses. The airfilter is fairly new so clean (well cleaner now since I took it out and cleaned out the bugs that had collected in the airbox).

M.

martins · Post by **martins** » Wed Dec 07, 2016 9:50 pm

So, I eventually took it into a BMW dealer to have diagnostics done. Their notes say:

C/O High Pressure system - Issue with high pressure fuel pump - New required

All in, they've quoted me £929.24

- doing a bit of research online, it seems as though BMW US have put a 10 year warranty on this part because of the high failure rate, is anyone aware of anything similar in the UK?

M.

martins · Post by **martins** » Tue Dec 27, 2016 5:14 pm

martins wrote:So, I eventually took it into a BMW dealer to have diagnostics done. Their notes say:

C/O High Pressure system - Issue with high pressure fuel pump - New required
All in, they've quoted me £929.24 - doing a bit of research online, it seems as though BMW US have put a 10 year warranty on this part because of the high failure rate, is anyone aware of anything similar in the UK?

M.

To close this one off, I called BMW UK complaints and they said that although there was no extended warranty on that part in the UK, they were 'aware of other customers' having similar issues' and I should contact my dealer and ask if BMW UK would 'assist' with the cost of the HPFP. I did this, at which point the dealer said 'thanks we needed you to phone BMW and ask about this - we'll now put the claim request through to BMW'. The result? BMW agreed to cover 50% of the parts, so £929.24 down to £524.64. Still a fortune to pay for a pump, but at least it was £400 off!

I hope this helps someone else in a similar situation.

Martin

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