27.5 MPG down to 23.5 MPG Mystery

#11

"RichGK" <RichGK (AT) hotmail (DOT) co.uk> wrote

Quote:

On 21 Feb, 17:33, "Ken" <Reply to NG only> wrote:
"John Laird" <lai... (AT) gmail (DOT) com> wrote in message

The only record I have kept is a monthly reading of the average MPG
according to the cars computer. Every month throughout 12 months was in
the
region of 27.5 and the months following the three events was 23.5.
Everything about my driving routine is so boringly the same week after
week.
My own feeling is the service as the car does not feel quite as it should
be
post service so now thinking of getting a smaller garage with old
fashioned
mechanic to take a look.

Ken

Do an old fashioned MPG survey on your car for a while and see if it
matches what the computer says.

Not sure if I can be bothered but thanks for suggesting.
Ken

#12

On Feb 22, 10:13 am, "Ken" <Reply to NG only> wrote:

Quote:

"Tim S Kemp" <n... (AT) timkemp (DOT) karoo.co.uk> wrote in messagenews:RbednS0WZ8530UDYnZ2dnUVZ8qCqnZ2d (AT) eclipse (DOT) net.uk...

Is the idle dead smooth or does it hunt a little? - google for VOLVO ETM -
it's likely to be the electronic throttle module (I'm assuming it's a
petrol turbo) especially if it has been driven economically.

Idle is very smooth and is at 650 rpm.
It is petrol and I am going to get into our small garage where the owner has
a V70 so is familiar with this type of car.

I'm no expert, but I would've thought the closed loop system with a
working lambda sensor would have trouble running at anything other
than optimum fuel/air ratio. A sudden drop in mpg would tend to
suggest something is knackered, or just maybe, the trip computer has
decided to lie or is poorly calibrated.

A quick emissions test would verify all is well with the mixture (if
it's been running very rich for months I wouldn't like to hazard a
guess as to what state the cat is in), or some careful brim-filling
and basic maths over a couple of tankfuls should verify the actual
mpg.

--
"Don't ask me, I'm making this up as I go!"

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27.5 MPG down to 23.5 MPG Mystery

Miscellaneous UK car topics Other UK car topics (uk.rec.cars.misc)

Re: 27.5 MPG down to 23.5 MPG Mystery - 02-22-2007 , 11:23 AM

Re: 27.5 MPG down to 23.5 MPG Mystery - 02-23-2007 , 08:20 AM