Renault Scenic (2003 - 2009) - 2004 1.9 dCi poor fuel consumption

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Thu 27 Mar 2008 20:40
2004 1.9 dCi poor fuel consumption - Ricden
I have noticed recently that the fuel consumption of the wife's Scenic has dropped by about 10-20%. The car has a fairly awful daily commute through very slow traffic but normally manages 36 mpg. This is now 31 mpg. Engine still starts well and no drop in power. The car was serviced at 2 years old and is now 3.5 years old. I've done the oil every 12 months.

Was thinking of taking off the air filter to see if it is clogged up and whether its removal improves matters. Can anyone tell me how to get at it? I can see the pipe behind the radiator but it disappears behind the battery.

I read a similar email a few weeks ago and someone wittily replied "if you can't find the filter maybe you shouldn't be looking in the bonnet!" But the Scenic engine access is very very cramped with its short bonnet. Any tips would be appreciated. I'm not completely thick - I have managed to change the headlight bulbs - no small achievement!

If the next step is a garage - not sure if it's best going to a Renault garage which doesn't care or a small private garage? (do they understand turbo diesels?)
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Thu 27 Mar 2008 21:00
2004 1.9 dCi poor fuel consumption - Screwloose

I'd think about an EGR valve fault or maybe a boost pressure sensor. A blocked air filter should flag a low boost code.
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Mon 7 Apr 2008 14:41
2004 1.9 dCi poor fuel consumption - hueycln
in a similar position...
I bought a 1.9dci megane 2 years ago. Initially the mpg were great anything up to 50mpg, now I am lucky to get 33mpg.
I have had it serviced and more recently, taken it to a garage for the air filter to be changed and also put it onto a diagnostic machine. The garage said there was nothiong wrong and vould not suggest what could be causing the low mpg. Generally it drives well and there has been no decrease in performance. I would like to buy a megane convertible but am reluctant to do so now as I dont want to end up in the same position again!!
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Mon 7 Apr 2008 15:10
2004 1.9 dCi poor fuel consumption - Screwloose
hueycln

That's a big drop in mileage; is there any black smoking?

Don't overlook the possible effects of brake drag - even a little can make a big difference.
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Mon 7 Apr 2008 16:38
2004 1.9 dCi poor fuel consumption - hueycln
hi
no, no black smoking
i've tried experimenting with different gear changes etc but noticed even on the motorway in 5th or 6th and not screwing it past 80mph Its still only ever getting 40mpg!
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Mon 7 Apr 2008 17:30
2004 1.9 dCi poor fuel consumption - Screwloose
If it's not the brakes; then there's something seriously amiss there - maybe a sensor reading or similar.

Although there are no codes, a good diesel specialist should be able to see what's wrong using the live-data.

Edited by Screwloose on 07/04/2008 at 17:31

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