I have owned this car for five years and throughout this time have cared for it in every respect and it has never let me down.
As a means of checking performance I occasionally use a twenty mile identical journey as a test to ascertain MPG.
Ensuring that everything is the same on every trip (same speed, same gear, same load, correct tyre pressures, no gear changing, similar weather conditions etc), I set the trip computer to zero and with engine already warmed up, obtain the same very good MPG without fail?.until now :o(
Last Thursday, the five-year service was carried out and on Saturday and Sunday I needed to make the same journey so, as usual, made the same MPG test. On both occasions the MPG was down by 10% !
I have not yet contacted the garage because they would probably point out that the ?service? was mainly an ?inspect everything? occasion which did not involve any engine adjustments and would then offer an ignition timing check at my expense.
Would anyone care to suggest why I should suddenly experience this disappointing change? I have deliberately not mentioned the actual MPG because most people would tell me how fortunate I am to achieve such good figures?with which I would agree but that is not the point of my thread.
TIA
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No offence, but I would question the validity of your testing. 20 miles, no gear changing, warm engine and using the trip computer?what are you trying to prove? Any small car would achieve a good mpg figure tested like that.
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Hard to imagine what the dealer could have done, unless they've used a much higher viscosity oil (doubtful that would make much difference anyway) or maybe adjusted the handbrake and left it binding?
I note the 20mile comments above, but when I refill our Jazz I always reset the trip, and it always quickly comes back to same MPG - very high 40's.
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1st off what did the garage change at the service?
you need to confirm what was replaced checked adjusted, at best they should have changed the 8 spark plugs and the air filter + oil filter.
The only 'fault' of the 1.3 jazz engine is the egr value -poor running acceleration.see link below:
clubjazz.org/knowledgebase/honda-jazz-2002-2008-fa...l
I recommend you ask the garage then if no new info --- give the car run out of 100miles + then recheck brim to brim.
Good Luck
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Does this engine have manually adjusted valve clearances? If so, were these chacked and adjusted during the service?
If the valve clearances had been maladjusted, this would easily explain the proble, as would a faulty plug, or poorly re-fitted air pipe.
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Many thanks for those replies.
Dereckr?.no offence taken! >>>what are you trying to prove?<<< As stated in O.P.>>>As a means of checking performance<<< I cannot think of a simpler way of self-testing that things are satisfactory under the bonnet. Surely anyone concerned with MPG would wonder why, in identical circumstances, the figure should drop by 10% and try to rectify.
Bill Payer?.Good suggestion but as you will see from page 12 of the Jazz service book, parking brake is adjusted at 4 and 6 year services?.not at 5?.and there is no change to the travel of the lever.
Ukjazz?.Also as stated in O.P.>>>the service was an ?inspect everything? occasion which did not involve any adjustments<<< I am grateful for your input and will check with the garage but rather doubt whether they did more than they charged for especially as they were one man short that day.
Number Cruncher?.I respectfully refer my Honourable Friend to answers given above re ?no adjustments made?.
So, I await any further answers with interest and will post here if I manage to solve the problem.
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Hello 007
I have owned a Jazz CVT for 21/2 years now, and the mpg [on the dash indicator] often fluctuates.
A few days ago I bought about £25 of Tesco unleaded. I have only used their petrol about twice in 21/2 years. On this occasion, the mpg readout is showing 58 mpg, the engine is running sweet as a nut and I have been using the air conditioner. In the time I have owned it, it has never shown this figure. Why? Who knows?
If your engine is otherwise fine, I would not be too concerned about a small fluctuation.
screwtape
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Is it worth "Ensuring that everything is the same on every trip", again, and re-trying to see if the worrysome result is a one off?
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We've had a 10 mpg drop in economy (so says the trip meter).
Started after it's last MOT at a Honda Dealer.
We used to get just under 60mpg on a motorway run and now its 49mpg.
I know they rev them very high as part of the CO2 checks - any thoughts?
Tony.
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SFAIK it is only diesels that are revved to near-destruction in the MOT. Is this a diesel Jazz?
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Our Jazz CVT always returned 50-55 in the early days. This has slowly got worse and recently we were lucky to get 46.
It's 5 years old (45000miles) this month and went for a service this week, I insisted on new plugs and valve shims despite the dealership insisting it don't need 'em.
I'm pleased to report that it seems to be back to its old self again with a mighty 62.3 showing after 110 miles of urban/town driving.
I'm happy but £375 lighter!
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I got a similar (10%) reduction in mpg indicated on the trip meter last week when it was very hot and I was using the aircon a lot.
Edited by L'escargot on 10/07/2009 at 10:08
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I had a starting problem with my audi A4, immediately after a service, the car would start but only after being turned over a few times.
I checked under the bonnet in all the areas that i thought the mechanic had been, near the oil filter were a couple of engine sensors, i pushed the connectors on more firmly, and that sorted the problem.
I would have a look under the bonnet, if you find nothing or the mpg does not return to normal, then i would contact the dealer, ask them if the correct oil has been used etc.
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