Clubjazz - Honda Jazz & HR-V Forums
Honda Jazz Forums => Honda Jazz Mk1 2002-2008 => Topic started by: guest780 on February 04, 2009, 10:24:39 PM
-
i have a 2004 jazz se.
it has now 95000 on the clock. its only given me 32mpg.
does any one know what i could do to bring the mpg up.
i drive in high gears and at a regular speeds.
-
Are your miles all short stop-start journeys around town? Is the car serviced regularly and have the spark plugs been changed recently? have the brakes checked to make sure they are not dragging (feel the wheels and wheel studs as soon as you stop the car after a journey, if one is a lot hotter than the others suspect that the brakes on that wheel are binding). Try adding some fuel injector cleaner to your petrol for a couple of tanks.
It's acceleration that uses up the fuel, try to change up as early as possible - the Jazz is quite happy to be in 3rd gear by 30mph unless you are going up a hill.
-
'the Jazz is quite happy to be in 3rd gear by 30mph '
Im normally in 4th gear at 30 mph
-
the car has been serviced all at the right times and has everything that needed changing at service changed.
i put £20 fuel and managed to get 150 miles. surely this cant be right for a small car like this.
i drove 85 of those miles on a one way journey on the motorway 65 miles in town. i this right?
-
Do you keep the tank topped up? Try waiting until the low fuel light comes on and fill-up the tank right to the top. I get better mpg on full tanks then I do if I keep it topped up weekly.
-
My sport auto over the last year & 10468 miles averaged 44mpg - best 1000 miles last March at 47.6 - December/January distinct drop some weeks of cold weather starts & local miles stop/start - feel a service will restore everything !
New Jazz ES i-shift on drive now so unable to say if service worked
I always fill-up & keep a constant record
-
i was thinking of using the injector cleaner petrol treatment.
maybe this will help. has any 1 used this and seen positive affect?
also could it be the type of unleaded i use. lately i have been using the cheaper unleaded at tesco. should i use the super unleaded instead.
-
Try a couple of tankfuls of super unleaded from one of the major brands, it may 'clean' the system out. I've seen an improvement in using super unleaded, *but* the figures remained improved if I returned to normal unleaded.
I doubt the injector cleaner would work though.
Your Jazz is quite high mileage, although I would still expect better than the low 30's.
-
Normal unleaded is fine, using the super stuff gives no benefit either economy or performance.
I use a petrol treatment once a year just as a precaution
-
Sick Motor?
Lost power, high fuel consumption, rough acceleration, exhaust smoke or just won't start.
Any of these sound familiar?
You may have a fuel system problem that could be fixed with the DIY application of D-TOX,
a powerful combustion chamber and fuel system cleaner.
A common fuel system problem affecting modern cars is the build up of combustion chamber deposits. Harmful deposits gradually accumulate and clog up fuel systems and the injectors, seriously affecting your engine's performance. Carbon deposits can also accumulate in the combustion chamber, piston and upper cylinder area, and unless removed with D-TOX they may eventually flake off, settle on the valve seat so the engine loses compression and then will not start. D-TOX breaks down these deposits to allow them to be exhausted without harm whilst at the same time acting as a powerful cleaner throughout the complete fuel system. D-TOX is formulated for use in all petrol / gasoline engines including those with turbo and super chargers, carburettors, multi valves, direct and indirect injection systems, and its catalytic converter friendly. We recommend using D-TOX once your engine is a year old and then again every year or 10,000 miles/16,000km or when reduced performance is noticed.
The above is the Comma petrol D-tox which I use on a yearly basis
-
Of course injector cleaners work - I use them about twice a year. Think of then like kettle de-scaler, no-one says that they don't work because the evidence is clear to see. Petrol from reputable garages (and I exclude supermarket petrol here because they cut costs by reducing the additives) has stuff in it to keep the injectors clean, but the less miles you do the more the injectors tend to clog up.
People think that the petrol that they put in their tank is really clean, but it isn't - its made from that yucky thick tarry stuff that is pumped from underground, and it leaves gunky deposits in your fuel system, especially the fine injector nozzles. Injector cleaners mainly have kerosene or similar as their main ingredient to dissolve this gunk. Anyone who has ever used carburettor cleaner knows how quickly it could turn a carb gunged up with sticky brown laquer into a sqeaky clean shining piece of precision engineering.
-
Normal unleaded is fine, using the super stuff gives no benefit either economy or performance.
I use a petrol treatment once a year just as a precaution
What I mean is it might clean the system out which in turn could improve mpg. Does it actully also have cleaners in the fuel like some say it does? Directly, no gain will be made in performance or economy as the engine won't take advantage of the higher octane rating.
The injector cleaner I got confused with those performance enhancers you stick in your tank.
-
Since manufacturers started sticking mpg displays in cars people have really become anoraks about their fuel consumption. Before the displays became common only a few people really checked their mileage against the amount of fuel they put in their tank and no-one challenged the car makers claims. The facts are that the following things all have a big effect on fuel consumption - start-stop driving and rapid acceleration, speeding**, not changing to a higher gear soon enough, short journeys, cold weather, incorrect pressure in tyres.
** Remember that air resistance is not linear - it increases rapidly as the speed rises. Even on modern streamlined cars the wind resistance really starts to increase your fuel consumption above 30mph - you will use about a third less fuel by travelling at 45mph instead of 70mph.
-
Try working out the mpg and not going by the trip computer.
Is this problem something which has only recently occured?
-
Forget the injector cleaner, just try the Italian Tuneup and some decent quality fuel (super unleaded or branded unleaded).
-
I just filled up and done the usual calculation on fuel use and it came up 47 mpg!!
The highest I have achieved since owning from new in apr 07.
-
Ref. super unleaded...
Super unleaded like BP Ultimate and Shell V-Power do two things. Firstly, super unleaded has a higher octane rating (98 RON Vs 95) for a higher resistance to engine knocking. Second....it contains more and better fuel additives to clean out the fuel system and prevent grime collecting in the system if used regularly. That's the theory....
Judging by my 1.8-litre Civic it's unlikely that the Jazz will see any benefit using super unleaded in terms of performance or economy. It may clean out the fuel system though. Shell, Esso & BP's 95 RON unleaded does contain some fuel additives over Tesco's so I would keep to this middle ground and use the branded normal unleaded.
TBH though, I think poor mpg is at least 75% driving conditions....stop/start, cold weather, etc, etc.
I would never use injector cleaners in newer cars, at least not still under warranty (in case anyone with newer cars are considering)
-
Has anyone given a thought to the fact that your favouite fuel supplier maybe supplying fuel blended with ETHANOL, it is well known across the "pond" where the use of ,ethanol blending is widely used ,can cause a 10% increase in fuel consumption.
It is difficult to get definative information on this subject but it might be worth trying a switch of supplier to see if it has any effect.
-
Mad Jazz, what did your previous cars do on mpg?
+
What changed the car the driver or the weather.....
-
I think that UK law would ensure that the petrol supplier would have to advertise it at the pump if the petrol was blended with ethanol.
I fill up with Premium petrol from Esso or BP occasionally and certainly notice the difference in smoothness and extra MPG. It seems to clean the system out and the effect lasts for a while - it may be cheaper to put in a system cleaner at between £5 to £10 a bottle every 6 months than to pay an extra 10p per litre for premium though.
-
I too have noticed with my previous 98 Civic VTi that the car ran better on fuels from Esso, BP and Shell. The engine always felt strained when using Tescos - ie. less 'oomph'.
I later discovered the reason why Tesco advertise their fuel as 'green', is because it does contain up to 5% bio-ethanol.
In Southeast, I understand Tesco source their supplies from the Greenergy Vopak terminal by the Thames - source of the contaminated fuel fiasco affecting Tescos and Asda a few years back.
http://www.greenergy.com/Products/index.html (http://www.greenergy.com/Products/index.html)
I've avoided the stuff ever since.
-
I understand that by European law petrol can be blended by up to 5% Ethanol I have yet to see a pump anywhere that states this. Can we assume that the lack of any notification means there is no ethanol present. I think not
-
From Car Magazine, March 2009:
"Virtually all pump fuel in the UK is likely to contain some ethanol, probably 5%".
"Ethanol contains 30% less energy than petrol so your touring range is slightly reduced".
-
If you want some definitve research info on this whole subject go to Car Bibles.com, click on to Fuel and Engine Bible and scroll down and read the results of much painstaking research by a Chris Longhurst. Be prepared though as there is a lot of info to similate.
-
Recently filled up with petrol and reset the trip meter at a garage that was at the top of a long steep hill. Left the garage and went down the hill, more than half a mile with foot off the throttle. By the time I got to the bottom the display was showing 138 mpg, although when I got home it was back to 42.
I tend to fill up anywhere that is convenient when I am low on fuel. I find that different brands froth up at different rates and make the pump cut out sooner or later, so you can get in more of some brands. Therefore if you want to calculate the actual fuel consumption accurately you need to return to the same petrol station and preferably the same pump.
-
Did a journey from Shrewsbury to Liverpool and back today, filled up soon after starting out and zeroed the trip mileage. When I got home the mpg display was 59.5, pretty good for mixed motorway and main road, didn't hang around either.
1.4SE Jazz GE with 55K on the clock - I normally cover 250 miles a week just getting to work and back and am getting about 54mpg just lately now the weather is 'warming up'!!
-
Just filled up and worked out the fuel consumption. It worked out at 47.5mpg!
Finally mpg nearer the official figures
-
Hi JazzyB,
my 52 plate with 103,000 needs a new EGR valve and the fuel consumption around town has dropped by 10mpg to less tahn 40, my best was 57 (B4 the EGR prob !)
-
Im not sure of the cost of an egr valve but its easily accessible on top of the engine. Left side of engine when standing in front.
-
Hi JazzyB,
I have already located it and if you take it off and give it a clean this will last a few hundered miles b4 the engine warning light comes on again. I just don't think you can get a new one unless you pay a lot for one from Honda.
-
Tim F, how did you discover the erg valve was at fault? My best results to date on a round trip to Lowestoft and back from Kent is 45 mpg. I was hoping to get this up to 50+
-
EGR (Exhaust Gas Recirculation) valve problems show up at lower revs (when the valve should be shut but is probably stuck open) - the EGR opens at higher revs anyway to allow some exhaust gas back into the inlet manifold and cool the combustion to reduces emmisions. If you car is running roughly at tickover and lacks low down power suspect EGR.
-
Hi JazzE,
The fault showed up as an orange management warning light and it failed the mot. Honda as is normal wanted nearly £100, but a local mechanic had the correct diagnostic equipment. His unit detected the fault and he removed the egr valve and cleaned it but the light came on about 300 miles later. I have cleaned it myself but I think it now needs replacing.