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Anyone any ideas why my fuel consumption is so high. Ive got a standard 115pd and im lucky if i can get 40mpg around the doors. I used to easily get high 40's around town and high 50's early 60's on a run. I know the cold weather doesnt help but when the mfa reads 33mpg i think something is up. Ive noticed recently that car seems to have a miss but only when just started. Recently replaced the MAF with a genuine VW jobby. Could this be faulty? Car still seems perky enough although on a recent trip to scotland I had my foot planted to the floor on a slight hill and i was struggling. Any ideas would be greatly appreciated.
 

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Try:

- Fuel Filter

- Air Filter

- Tyre Pressures

- Split/Detached Vacuum Hose

If you have VAG-COM run a maf test (or disconnect it and see if you notice any degredation - if not, it's likely to be faulty).
 

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I thought my maf was faulty, but not so sure, as i took it out and cleaned it. Car felt better and mpg improved slightly, but majorly i put a k and n air filter on it ?40 euro car parts on team valley.

I would do a vag com test it want, i do charge. in sunderland also
 

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Do you do a lot of short journeys?? My fuel consumption was very low then went on a long run M1, M6 and it's improved. Perhaps cleared all the crap out.
 

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I also have a 115pd with 55k on the clock. my MPG has dropped over the past 6 months from average 45 to 40. not sure why, I have put a new air filter on 2 months ago and just had it serviced.

I have a Merc maf on so Im going to try cleaing the old VW one and putting that back on. Also going to give the Millers diesel additive a try.

let me know if you sort the problem out!

wheres the fuel filter located?
 

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Strange this.

I've also noticed a drop. Could it be something wrong with the PD unit ? Ours were the first Pd's out and hence the oldest. I wonder if there is a connection and long term usage, are the newer PD 130's & 150's noticing anything ? If you ever go to the TDI.com site (Canadian) they endlessly go on about cleaning their intakes which soot up and restrict airflow into the engine.

This could be something that is effecting us to some degree but not as much as in the USA / Canada as our fuel is of a much higher quality and therefore less prone to sooting. I've often thought about this happening and have read a few threads about it ON HERE so it's a real problem. I've also considered cleaning out the intercooler on my car as I'm sure it must be half full of oil by now (have you ever taken an intercooler hose off and noted the amount of oil in the hose ?)

Although my drop in MPG isn't that dramatic I think the service items as mentioned in the previous posts above and the 'dirty' intake all contribute to the drop, but I think the single biggest factor is the lower ambient air temperature and increased warm up time / increased fuelling.

Are those of you experiencing the biggest drops in MPG doing short journies ? I myself travel between 100-150 miles each working day which might explain why my drop is less noticable as the engine is at working temperature for longer so the cold start is averaged out.....
 

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I'm almost certain it's ambient temperatures and short journeys causing this . Also uses more fuel if you use the heater whilst the car tries to warm-up, probably because it saps the engine of the heat it's generating thus prolonging the warm-up period.

My commute is a mere 5 miles and I barely see 34 MPG since I'm in town traffic then get a very short blast at 50 MPH on a dual carriageway.

Recently went to the Peak District with three passengers, stuck to the speed limits all the way and managed to get 47 MPG (3-8 degrees Celcius ambient temperature).

I've driven a 130PD Bora from cold and not noticed such a dramatic drop in economy. . .
 

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I got my car serviced at VW this morning. Mentioned to them that the performance and economy had dropped lately (43mpg instead of 50+mpg average). I also had put it down to the cold weather.

They put it on the diagnostics. Guess what ??? Bad MAF Sensor.

To be replaced under warranty next week. Result.
 

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Hi,

I've got a 2000(w) reg 115PD too. I've seen the consumption fall from 47-50mpg to (currently) around 37mpg. I've also seen problems with the temperature fluctuating wildly which led me to believe the sensor may be faulty (new parts awaiting collection from VW this w/end). People mentioned about the MAF sensor as well. Is this also easy and relatively cheap to replace (I've heard people fitting alternative vendors MAF's before).

I was also considering fitting a K&N Air Filter (ebay around ?45 http://cgi.ebay.co.uk/ws/eBayISAPI.dll?ViewItem&category=9889&item=4508397991&rd=1&ssPageName=WD1V ) and/or the K&N induction kit.... (one for sale here http://cgi.ebay.co.uk/ws/eBayISAPI.dll?ViewItem&category=36680&item=7933311161&rd=1&ssPageName=WD1V).

Are either of these worth looking at? Do they really make a difference? I've tended not to fiddle with my motor till now and let the local dealer sort it but as time goes on i suspect more stuff will need replacing so I'm considering doing a few of these things myself. Also, if anyone can recommend a local seller of performance bits like this (Leicestershire) that would be great. I'm no mechanic (I know where to put the water and oil in).

anyway, feedback on any of the above would be most welcome...

regards

Bob.
 

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wouldnt go for the K+n personally, they are a oily filter which has been known to kill mafs, a Green cotton one is the recommended way over on seatcupra.net.

and on a side note both me and my dad have seen a drop in economy to just under 50mpg, about 48-49 from the usual 52 or 53mpg over the last few months..... but i am putting it down to the weather.

I turned my tuning box off as this was making my economy drop to below 45mpg down the motor way which was terrible, think it was overfuelling too much, i should really back it off now the colder denser air is here.
 

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After my service, I drove 400 miles on the M1 yesterday. About 75-80mph. Got 48mpg, used to get 55mpg.

New MAF to be fitted Tuesday. I'll report back with the difference in fuel economy (hopefully).

I took my car on a gentle (60mph) run on a known route of mainy dual carraige way of about 20 miles (zero traffic). I got 47mpg. Then took my friend's GT-TDi 115 on exactly the same run at the same speeds. Got 43mpg. Neither were brilliant. I would have expected 60+ as I have achieved 65+mpg driving like that in my car before. Very strange.

Old cars (in the 70s) used to have a 'flick switch' near the air filter for winter/summer. If it is the cold weather affecting our cars, is there something which needs to 'emulate' this switch ???
 

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Old cars (in the 70s) used to have a 'flick switch' near the air filter for winter/summer. If it is the cold weather affecting our cars, is there something which needs to 'emulate' this switch ???

Most petrol cars do still have this 'flick switch' but its operates itself (thermo controled), it flicks over a flap which directs hot air from around the exhaust manifold into the intake system to prevent the petrol from freezing although its not as serious an issue these days all cars being injection so that wont affect the diesels in the same way, sorry.

As for the engines warm up time in colder weather this will affect the fuel consumption slightly but not majorly, if theres a major drop from what your used to and theres no faults stored I would suspect in order - Coolant temp sender, MAF, fuel filter.

Hope you get it sorted whatever it is.
 

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well in that case im gonna have a word when i service my car next. Ive got a '03 PD100 and my fuel economy is poop! I mainly do short journeys, but still on the motorways im not getin very good fuel economy! At the moment its on like 33mpg, and when im on the motorway im getin like 40mpg! Is something very wrong here?
 

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Deffo Gengar. I've got the same engine in my Polo. I still get about 50mpg on the motorway and I'm not happy with that (as I do drive fairly slow). With 33mpg it's hardly worth driving a diesel from an mpg point of view, bearing in mind the differences in fuel prices at the moment.
 

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After my car came out of its service, i was told my Lambda sensor was on its way out. Dont ask me what it does, but i was told it affects fuel consumption. My car is also clocking on at 56k~

i diagnostic test should reveal whether or not the sensor is dodgy.
 

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Hi

When i first bought the car a few months ago, the fuel consumption was briliant (about 55mpg)[:)]

Since I have had the following

Mudflaps

Alloys 17"

Lowered (although i don't think this should have had a negative impact)

The figures have been going down (40s)[:(]

Checked the air filter, had a few black marks but nothing major. Used the Vacum to clean it up (although not sure about this)

Noticed that some people have mentioned it maybe the MAF .

Is this the thing next to the air filter

Anyone in the Bradford area with a MAF tester

Or should just disconnect the cable above the air filter and give it a drive

let us know

thank you in advance
 

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Strange you all mention this, I was wondering about the fuel consumption in my new car today and I also drive a 2000 plate 115PD. Mines having the MAF changed for a genuine volks part and also going on the diags to see whats wrong with the traction, will post if i find anything else that could contribute to the fuelling.

Mart
 

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Well, had the MAF changed today and the fuel consumption has shot through the roof. Was sat in traffic most of the way back and the average still went up by 4 MPG.

The ar also feels so much more responsive now, so much more power it unbelievable!

Mart
 
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