Fuel Efficiency drop

[madasahatter]

I have noticed over the last couple of weeks that the Cerb seems to be using more fuel than it usually does to cover the same distance. The motorway stuff seems to be normal, but the stop start work seems to consume more petrol than I am used to.

You might say that I have been booting it more , but I don't believe I have.

It isn't a particular problem at the moment, but I am aware that sometimes a change the behaviour of the car can indicate a problem, so I was wondering if anyone here had seen the problem before, and how it was resolved.

I would guess that I am getting something like 50 miles less to a tank of fuel.

TIA

[olly]

How much are you getting on a tank on normal A/B road driving ? If it's between 200 & 250, then I'd say you've got nothing to worry about (fuel consupmtion drops on all our cars in hot weather)

[madasahatter]

I'm getting about 150-170 miles to a tank.

I appreciate that this is quite possible if you get your toe down, but I have done 90 miles of motorway in there somewhere.....

Seems a bit low (I was getting 200-250 to the tank before as you say).

Steve

[olly]

I would speak to an independatn or a dealer.... 150-170 is 12.2-13.8mpg. And even by Cerb standards thats low ! You've not sprung a fuel leak have you ? (does boot smell of petrol ?)

[madasahatter]

Hmmm. Sounds like something might be up then....I'll get it checked out. There is (of course) another explanation, which is that the Fuel Gauge is misreading, and so I am not putting as much fuel in. I'll check it more thoroughly when I fill this time.

Thanks for the advise Olly.

Steve

[danielson]

i had the same thing once on my bimmer (apologies but i am looking for a Tiv honest!), and about the same 50 mile drop in range per my usual tank. It turned out to be the lamda sensor needed replacing as it was running too rich. Another thing to poss check, the calipers arent sticking on one of your wheels? Smell/feel your wheels after a run out if one stinks or is really hot then the pads may be rubbing which could add to overall drainage of fuel and to be honest with the power of your cerb you may not notice the brake is on one of the wheels :-)

[GCerbera]

danielson said:

i had the same thing once on my bimmer (apologies but i am looking for a Tiv honest!), and about the same 50 mile drop in range per my usual tank. It turned out to be the lamda sensor needed replacing as it was running too rich.

Indeed, this is a possible worrying cause.

If the sensor is going or gone, it will pump fuel into
the exhaust which if left would result in:

A) A shower of alarming sparks out the back of your car.
B) Burnt out costly cats.
C) A very leathal situation with a red hot exhaust under you.


See this thread and check out the picture! :
www.pistonheads.com/gassing/topic.asp?t=36143&f=6&h=0&hw=cats

Go create some weather...
Graham
TCR The Cerbera Register

www.TVR-Cerbera.com

[jj99]

The strange thing is after that incident had lambda sensor replaced and full set up on the car. It now runs really well and cat does'nt heat up anymore but is much worse on fuel, maybe something else causing the problem.

[anonymous-user]

Car is most likely out of tune. Even a slight variation can cause the car to use more fuel.
Get it to an expert and ask him to run through the setup again.

[gazzab]

there are lots of sensors (eg air temp) that contribute to mixture. I understand that these can be a problem BUT it is obvious when hooked up to the software ie the readings will be wrong.

[madasahatter]

Thanks for the replies - definitely one to get to the dealer fairly quickly, just in case the overfuelling gets so bad as to be damaging something else.

All booked in. I'll try and remember to report back findings so that the archive of the problem is complete on here.

[Julian64]

Just for info. Since this link I recorded mileage. 187.5 miles using 42.18 litres makes about 20-21 MPG. Thats probably equivalent to urban cycle driving

Cerbie 4.5