Excessive Fuel Consumption in 96 V6

[Ezza]

Hi all,

I am a new owner to the MX-3 (or otherwise known here in Aus as the Eunox 30x), have only had it 2 weeks but I am concerned about the seemingly unusually high fuel consumption of the car.

The car has done 130,000 km's and is due for that service now, which I have it booked in for with a Mazda dealer/service centre, although thinking of changing that and using a regular service centre due to the high costs of using dealer service centres.

It has a full service history of being logbook serviced every 10,000kms by mostly a Mazda-familiar service centre (interstate from where I live however) since new, so should be in good condition and has also had timing belt replacement at 100,000km's (however cannot find any evidence of water pump being changed at same time - unusual). The car is stock except for a pod filter having been fitted (which looks quite squished in and a little out of shape as it is quite large). I must say here also though that when I purchased the car it was quite weathered paintwise and the engine and bay is filthy and dusty so looks not to have been all that well looked after in the last few months with last owner.

I noticed from the MX-3 site that the car should use approx. 11L/100kms for city driving and I *think* these cars have a 40L tank fitted? (Please someone correct me if I am wrong but I filled up today and it took 38L and the fuel guage was registering empty). So going on these figures I should be getting on average 440L from a tank city driving.

However, last week I filled up with 98 octane Premium Fuel as the car seemed perhaps a bit sluggish and I was unsure but thought I could hear some very faint chattering noise under load esp with the A/C on so thought I would try to to see if it made any diff (which is seemed to but then I am coming from a big 3.8L V6 VT Commodore, so may have just been used to the quietness & power of that engine). Anyway I got 350km's out of that tank or premium fuel which should really give me a few more km's than regular unleaded anyway so as you can see it is using quite a lot. Now admittedly, I did give it a bit with a couple of hills runs on the weekend and also have had the A/C going but surely that wouldn't make a difference of 100kms out of a tank?

Can anyone else tell me what kind of economy they get out of their car? Also any ideas what might be causing this problem? I am thinking about getting a new pod filter, replacing sparkplugs and maybe getting the timing looked at but any other suggestions would be much appreciated. Also has anyone fitted one of those sprial metal fuel savers off ebay on their car, did it make any difference?

PS: Sorry about the huge post but the more info ppl have the more you should be able to help! Thanks!

[DimaK]

i would start with air filter.sparkplugs.timing will play a role as well.i get 10L\100km in ford probe in the city.
try putting seafoam thought it.about magnetic fuel savers.......it doesnt make sence, they say the molucels in fuel are all messed up when they r in ur tank.they are not.now using higher grade of fuel wont make difference right away.and ac will make your milege worse by 20 percent

[Ezza]

Hi all,

Dimak thanks for the tips however I think the problem I have is now a faulty fuel gauge. Anyone else have this problem? I found out looking in my spec book that the fuel tank capacity is 50L yet when I filled up from "empty" or so the gauge said, it only took 38L, so obv was not empty! Hence why I had only got 350kms so far. I find it odd that the fuel gauge would say empty b4 it is, normally the problem is usually the other way around where the tank becomes empty b4 the gauge reads it is... If anyone else has had this prob and/or can tell me how to fix it would be much appreciated!

Erin.

[mitmaks]

I dont fill mine up until little orange light turns on and after it turns on I can drive around 30 miles easily.

[projectzemx3]

it could possibly be over fueling due to bad oxygen sensors. did it pass its emissions test? do you have emissions tests in aus.?

[yureno]

i gotta agree, im here in aus, i filled up wen i hit the fuel light, she took 35litres b4 the fuel bowser clicked, i only travelled 320kms before fuel light lit agen

[neumann]

My two cents (or 1.8 cents AUS)

I have a 94 GS v6

Fuel tank is 50 litres. When empty light goes on I can add about 38 litres. I don't necessarily think that 12 litres remains although it is probably pretty close.

I kept mileage for a while and averaged a little less than 9 litres per hundred kilometres in mixed city and highway driving. I think 11 l/100 km in city is a little high.

When I encountered drivability issues my consumption went up, but not much. I had a small crack inn air intake hose and 1 bad spark plug. The combination was a little bad to troubleshoot because both would cause stumbling during acceleration.

Anyhow I concur with others. Check the air intake hose - there can be leaks that only occur with engine load when it flexes. Definitely look at the spark plugs to check condition and gap.