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Poor fuel economy

K

kthaiss

New member
After driving my recently purchased 1996 C4 for about a month now, I have noticed a steady decrease in fuel economy. I'm now averaging about 14 mpg (city & motorway driving). This seems pretty low to me even for city commuting.
I've also noticed that the interior smells heavily of exhaust fumes about 30 sec- 1 min after ignition (it goes away after a while) and that the oil pressure is steady at about 4.5 while reving (not too bad but higher than I would expect). All of this leads me to suspect a blocked catalytic converter.

Anyone have any experience with these symptoms? Or am I just being paranoid?

Thanks.
 
I think that a '96 car should have some onboard diagnostics monitoring the emissions.
A trip to the OPC or suitable independent should be able to tell you if there is some obvious malfunction.
Although if there is a problme with the cats the check engine light will come on (at least on the newer cars).

It should only take a few moments.
 
my average is about 13mpg at the moment.... with about 80% of city driving.... but that's cause I'm haveing TOO MUCH FUN ! [:D]

I'll prob' only ever get up to the teens on a regular basis.. but that seems ok to me..

although easily to about 24mpg for motorway runs.....

but is low mpg is the price of loving the 911 experince .. fine by me ! [8D]
 
Oil pressure should be around 2 when hot and at idle and at 4.5 - 5 when revving (so you sound OK there). Fuel economy could be a little low but as Sundeep says it depends on where and how you drive the car.

However your interior smell is not normal at all and could be related to either the exhaust system or the heating system (which uses the engine as a heat source but should not cause an exhaust smell in the car).

An OPC or independent could check the ECU system for any error codes being generated by the car (it is not unknown for the check engine light to have been 'disconnected' somehow).

Ian.
 

ORIGINAL: ian_uk

However your interior smell is not normal at all and could be related to either the exhaust system or the heating system (which uses the engine as a heat source but should not cause an exhaust smell in the car).
Click to expand...

yes.. as ian says this ain't normal !

prob' more of a worry than bad fuel economy !
 
In the past have checked my fuel consumption and it was about 22mpg.

Thing is not too worried as I tend to drive with some exuberence[:)]
 
I only checked MPG when I drove to LeMans for the 24hr this year and achieved about 25/26 MPG driving in 6th at about 85MPH.

Usually get about 300miles +/- from a full tank of juice depending on driving style/right foot.....

Although fuel economy has dropped since putting the mufflers on as I just love the sound !!! [:)]
 
I normally get between 20 and 25 MPG and always drive the car hard. On the track it drops to a wonderful 12 !
 

Although fuel economy has dropped since putting the mufflers on as I just love the sound !!!
Click to expand...

I managed 27 ish last year on the way to Nurbergring - this did take a dive after a couple of laps of the Nordscleif[8D]

Normal av MPG though was a creditable 17/18 - 25 on a run.

RSB's do make a difference though!
GPM
 
after a few motorway runs.. the trip computer is advising that I am averaging about 22mpg.. which ain't that bad [&:]

but will drop down towards 15mph with toen driving
 
Thanks for the feedback. Sounds like I may be running a bit low (particularly for motorway driving) but there seems to be some variation out there.

Mentioned it to an independent and they think both the low fuel economy and the exhaust smell may be related to the engine bay wiring loom recall issue. I'll need to get that replaced by an OPC and see what happens...
 
Oops! That was just a typo in my signature. Its a '96 993 not a '93. As far as I know its not an import. VIN # WP0ZZZ99ZTS311619.

The loom part number was checked and found to be 993-60701607 which, I believe, is the recall part.


...It's my first posting but I'll get the hang of it eventually. [8|]
 
Hi Karl

I run a 964 and had an internal heater hose split and caused a lot of cab heat along with engine/exhaust smells. On mine the hose ran from the passengers floor well into the rear of the dash, might be worth a look.

MPG, get the best on Super unleaded at around 20/22MPG or 300 tank to tank. On run I'll get 25 ish, other half as got it to 27!
 
hum

i dont seem to get more than 220 on a full tank of super unleaded......however i guess i only
recently bought the car and enjoy listening to the free "soundtrack" and am thus exploring the
upper ends of the rev counter more frequently than i should [:)]
 

ORIGINAL: sanjay

hum

i dont seem to get more than 220 on a full tank of super unleaded......however i guess i only
recently bought the car and enjoy listening to the free "soundtrack" and am thus exploring the
upper ends of the rev counter more frequently than i should [:)]
Click to expand...

aye.. had a few of those days.. and still do now and again....[:D]

although did get through 80% of the tank at Bedford a few months ago !
 
Ok

been a bit more sensible in last week

Managed 248miles before petrol warning light came on

this was using super unleaded from sainsburys and mainly london driving......

is this an acceptable mileage?
 
not bad till the petrol light, but as I've got an OBC I can normally go another 30-40 or so miles till I have about 5 miles left....

so if you are only filling up when the light comes on then no to bad.... I assume you put in between 50-59 litres ?
 
I get about 27 mpg with or without superunleaded. That's about 370 miles before the warning light comes on. Currently the gauge reads just under half with 256 miles on the trip meter.

That's driving with economy in mind, but I reckon I drive as fast as I can whilst staying safe (and keeping to an indicated 75-80 on m-ways and d-carriageways) and little if anything passes me. The 993's not as economical as my A4 (35-38 mpg), but then it's nearly twice as powerful and I use some of the extra.
 
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