'89 929 Fuel usage

[Troys_81]

Hey Guys,

Just wondering if any of you had an idea about fuel usage or where I may be able to find some information regarding the fuel consumption of these models? Currently I'm getting a bit over 17.5L/100km(13.4 miles per gallon). Modern cars I know built in Australia with bigger engines are getting way better fuel consumption. Is this right as I checked a while ago with the mazda dealer and they said when new the fuel consumption was 15L per 100km. I guess mazda hadn't worked out how to get good economy with new technology(the recent introduction at the time this model was made of efi).

[donbryce]

Hi. Read 9ine deuce's thread about his mileage, which includes some on mine as well. Looks like the car was never designed for economy. 9ine's transmission is standard, however (rare), and I'm running the automatic.

I was wondering if anyone had noticed any diference in the 'power' versus 'economy' gear change settings on this tranny on mileage?

[9ine Deuce]

my mileage is pissing me off, I put in 59L, I have 235kms and about a quarter tank left, I was expecting way better, looks like Ill end up with 280kms from 59L, whats that work out to ??? I used to get 330kms average and got 510kms to a tank of all highway mileage

I think my O2 sensor is ******, my mileage is still crappy after the motor vac, although the engine is a little smoother

[Troys_81]

Hey Don,

The econo vs power setting is a valid argument. Next time I fill up I'm going to leave it on power and see how it goes. The only difference that I can notice is the shift points. I don't think there would be a lot of difference between eco and power. I'll read 9inch's thread on fuel economy. I am just stumped as it is a 3L engine compared with bigger 6's that have better fuel economy.

Hey 9inch deuce worked out that based on your record its getting 21L per 100km . I don't know how hard you drive it though....

[9ine Deuce]

yup, 285kms to 59L of premium winter gas, man wtf is wrong, I dont drive my car hard, I shift at the recomended shift points, sometimes earlier

[9ine Deuce]

just got 140 kms to 25L of regular fuel

[donbryce]

Filled up yesterday...the weather has improved, lots of days in the plus celcius range now here...still only short around-town trips:

55L/300KM = 5.5 L/KM (means squat to me)

Equivalent conversions:

12 Imp. Gal/186.4 Miles = 15.5 MPG (I can relate to this)

14.5 US Gal/186.4 Miles = 13 MPG (for our US members)

142,000km on the OD of my 1988 929, no plug/wires/rotor/fuel filter/air cleaner changes since purchase in May 2002.

[donbryce]

9ine Deuce's 140 kms to 25L of regular fuel (5.6L/KM) =

5.5 Gal Imp/87 Miles = 15.8 MPG

6.6 Gal US/87 Miles = 13 MPG

I'd attribute the lost mileage since you lived in Vancouver to (a) warmer weather there, ( more short trips here than there, and © the viciously cold winter weather here.

Let's hear from Australia, Troys 81....

[9ine Deuce]

23L of fuel and I got 110kms, this is what I dont understand, my mileage varys too much, I sure that something is wrong, do you think it could be the fuel pressure regulator ? a guy on the MPV club said he replaced his and got 2 more miles per gallon

[vaughnc]

I usally see 22/26 MPG when the car's tuned up & running right. Note I did replace catalytic converter & pre-cat at 125K miles due to an exhaust leak, so the exhaust backpressure is probably less than the orginall OEM exhaust. That means better fuel economy.