Audi 100 s4 fuel consumption

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Thu 14 Nov 2002 14:30
Audi 100 s4 fuel consumption - car fanatic
Hi I have just bought a 1994 Audi S4 Avant Auto, it has been chipped to stage 1 level and has 270 HP, it is a great car, fantastic to drive and fast the only trouble is I am only averaging around 15mpg, for a mixture of town and dual carriage way driving, I do drive the car quite hard but my wife drives it mainly and very sedately and the mpg still does not increase much at all. Does anyone with a similar car get fuel consumption this low or does it point to a fault with the car, the car runs well and I use Shell Optimax unfortunately I cannot afford to only get 250 miles from a £55 tank of fuel. Any contributions would be greatly appreciated.
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Thu 14 Nov 2002 14:43
Audi 100 s4 fuel consumption - madf
I suspect the chipping relies on strenthening the fuel mix and removing the original ECU's cutting off fuel on the overrun..

Hence the increased power.. and the worsened fuel consumption.
madf
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Thu 14 Nov 2002 15:19
Audi 100 s4 fuel consumption - RichardW
15 sounds a bit low, I'd have epxected somewhere around low 20's, maybe 25 if you really tiptoe. Maybe the cold start mechanism has gone a bit haywire and is keeping the mixture too rich. Unfortunately as with most modern engine complaints you need to get the diagnostic computer to talk to it and see what it is thinking!!

Richard
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Thu 14 Nov 2002 15:43
Audi 100 s4 fuel consumption - teabelly
Parkers suggests 26 mpg average for one of these but that is standard tune. Was there a manual version made of this car? If you are driving it reasonably hard and with some town driving then you may not get much more than 15 mpg. Have you checked you don't have a petrol leak anywhere just in case it is just seeping away? Who made the chip? Some are a lot better than others and the worst ones just chuck in fuel regardless of whether it is burnt properly or not. You may just be unlucky and have one of these chips.

It might be worth trying it on ordinary unleaded for a couple of complete fills and see whether economy changes. Unless the car has either an octane sensor or has been changed to take advantage of higher octane fuel it probably won't give much improvement in performance and economy (it could even be worse than ordinary 95 ron).
teabelly
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