Fuel Consumpstion in 2 different Libertys

AlpineRaven · Post by **AlpineRaven** » Tue May 15, 2007 10:25 pm

G'day,
I am hoping you could point out a few things here -

Let me get back to the point, I used to have 1994 2nd Gen Liberty sedan AWD 5MT (was around 240,000kms when written off in Aug. 2006), engine was kinda smokey in cold or if driven hard as 4th Cylinder was on way out, oil was always black after 1500-2000kms. Used to be able to get around 8.4 - 9.4 litres per 100kms, I remember when I bought it, about 2 months later I bought it, it had cracked "Y" exhaust manifold and I replaced to 2.0 litre Impreza manifold with Impreza O2 sensor, that Impreza was written off at 60,000kms and looked so clean etc so fitted it on mine, I cannot remember the fuel figures before I changed it...

Now, I currently own 1996 Liberty wagon AWD 5MT, engine/car is now at 250,00kms, oil colour is always golden brown, never goes black between service, previous owner and my ownership is always well serviced on the dot. Fuel consumption is around 9.5-10.8 litres per 100kms and until recently its getting worse - never gets in lows 9 litres per 100 or below, for past 2 months its around 10 litres per 100 close just under 11..

What could it be? I've run fuel injectors stuff thru last week - no change. Would it be possible the Oxygen sensor be on its way out? How can I test it?

The butterfly/inlet manifold/air flow etc is all clean - no sign of restricted air flow. Transmission and rear diff. has been changed 2 months ago - approx. 8000kms ago. Is it possible Wheel Bearings be on way out? - I have no history of bearing replacement as its not in the books.

Tyres are 15"65/195 at 36psi all 4 wheels, same size tyres. (NB - 1994 Liberty had 16"/50/205 mags)

What else could it be causing it to use more fuel?
Cheers & thanks
AP

AlpineRaven · Post by **AlpineRaven** » Tue May 15, 2007 10:34 pm

Oh I found Oxygen Sensors on ebay to get them to Australia will cost me around $33AU, are they any good do you know?
Cheers
AP

90brumby · Post by **90brumby** » Tue May 15, 2007 11:42 pm

have u tryed fuel filter

brumbyrunner · Post by **brumbyrunner** » Wed May 16, 2007 6:32 am

blocked air filter will cause exessive fuel consumption
failing that, give it a really good tune up. O2 senser, TPS, timing, plugs, etc...

Outback bloke · Post by **Outback bloke** » Wed May 16, 2007 7:22 am

Is it down on power at all? Or just using more fuel?

An O2 sensor will help with fuel economy but the variance in the computer is not great. It does help with economy is what I am saying but I think it could be some thing different.

I would be putting my money one the exhaust change you did. More so the cat being blocked/unblocked rather than the oxygen sensor making the difference.

With it being well maintained as you say then you can pretty much rule out plugs, leads, filters etc.

Unfortunately there is no 100% true method of testing if the cat is blocked or not. (By blocked I don't mean complete just full of crap from over the years) I do know that if economy is bad and power is down it is a pretty good place to start looking.

AlpineRaven · Post by **AlpineRaven** » Wed May 16, 2007 7:25 am

I would rule out Spark plugs/Tension leads/fuel filters because they were replaced 15000 kms ago and Air Filter replaced 5000 kms ago.
Hmm Cat could be blocked... I'll put money towards O2 sensor..

Do you know if these ebay O2 sensors are any good?
Cheers
AP

daza · Post by **daza** » Wed May 16, 2007 8:11 am

OK i'll ask the silly question,
Did the transmittion and diff change go to a taller ratio?
Daza.