I am getting about 17 mpg(around town, low traffic) in my tracker. Not sure if this is normal but for such a small vehicle i was expeting a bit more. This mileage is almost the same or worse then my previous car which had a V8. Only thing not stock is my cat is removed because it got rusty/damaged and replaced with a length of pipe (mpg was about the same before anyway). Anything known for bringing mileage down without a CEL i can look into? Or maybe this is just normal.

thanks

First thing I would check is your CEL bulb - does it light up for the test when you first start it?  I have a hard time imagining that low of mileage on a 2-door without a CEL on (unless you have REALLY big tires).  After that, I would check air cleaner, then O2 sensor, then MAF sensor, etc. (starting with cheapest items then moving to more $$).

My wife's old 2-door '89 hardtop would get 26 - 30 mpg, but it just had the old TBI 1.6L.

First thing i did was check that, CEL is on when key is at ON with engine off. How does one check to see if a o2 sensor is working , what about MAF? just clean them off? I'll pick up a new air filter today, only a few bucks might as well.

update: i took a look at the air filter today and it looked very very clean, so it looks like it must be something else.

I know you can clean the MAF with SENSOR SAFE carb cleaner.  As for the O2 sensor, good luck getting it out of the exhaust - they're usually rusted-in tight.  Once it's out, you could clean it too, but I've never heard of that helping . . . better to just replace it while you've got it out.

If you have a shop manual and a multi-meter, there are test procedures for almost every sensor on the rig, but chances are if they're not setting a CEL code, then they will pass all of those tests.

Another thing to think about - your sig. says automatic trans. - is it working properly?  Or is it slipping and/or delaying shifts?  Tranny problems could lead to low mileage.

One last idea:  was your muffler checked out when the cat. was removed?  If the cat was damaged and dumped its contents, it could have gotten blown back to the muffler and plugged it up.  A plugged muffler would certainly lead to low mileage.

Good luck!

i have some o2 sensor safe carb cleaner around, i'll try that. The trans seems to be fine to me but i have never driven another auto tracker/vitara so i don't know what is normal, but it seems that it shifts and takes off normally.

I changed the spark plug insulators on mine and made a big difference but mine has 250k kms.  The springs inside that carry the current were rusted. They were 13 bucks each so why not.

Next im going to check the vaccum hoses for leaks. O2 sensor is 150 bucks (maybe cheaper online?) so that would have to save me a lot of money in gas to pay for itself.

mine only has 124km, only a youngster. getting a new air filter(it actually looks pretty dirty in good light, and cleaning the maf tommorow. we'll see if if anything happens. First time in my life i wanted a CEL lol

Just a suggestion - how old is that O2 sensor?

They are maintenance items, pretty much like a spark plug or a timing belt, and depending on when the vehicle was built, the anticpated life span may vary from 50,000 to 100,000 miles.

I just swapped out the O2 sensor on a Mitsubishi Pajero iO (a compact SUV about the size of a 5 door Sidekick), that I picked up last year - the replacement cost me about $35 from Amazon, and judging from the improvement in fuel economy, I'd say I'm going to save that $35 in fuel within about two months - not bad for $35 and an hour of my time.

I had no CEL and I did check all the sensors with a meter before the swap, the O2 sensor gave me bogus readings, which might have been because I let it get hot enough before the test, but, given the mileage on it, and the relative low cost, I decided to swap it and see how it would work out.

I'm changing the plugs on it next - and those actually cost me more than the O2 sensor.

A leaky exhaust manifold gasket or cracked manifold can cause outside air to be drawn into the exhaust stream  and make the o2 sensor think the engine is running lean and richen the mixture way up.

just for reference, in the last month i figured out I've been getting just shy of 20mpg. Of course mine is a 4 door and isn't very stock.

Your 2 door should be getting better mileage then mine. Here's hoping you figure out what's causing the problem 

I'm thinking 24 town and 26 highway would be more in the 'normal' range so you have been losing alot of mileage.  My 4 door with a 2 liter is pretty reliable on getting 23-24MPG around the country where I live with slight modifications as long as I don't put my foot in it.  Better mileage in the summer months, worse in the winter.

there is defiantly no exhaust leaks, that i can hear anyway. i just got one fixed actually. I think the o2 sensor is the one that come with it from the factory. I see a few fairly inexpensive ones on the web. Is there 2 of them on these rigs? if so which one should be replaced, or both?

Yes there is two sensors, the front one, aka the primary sensor is the one used to determine the A/F, the secondary sensor is placed after the cat and is merely there to determine if the cat is functioning.

Stear clear of the budget E-bay sensors as they usually are substandard seconds that are slightly out of calibration. Quality does indeed cost $$$


Have you reset the ECU ?

Whenever the fuel blend is changed(fall and spring) the long term fuel trims in the ECU's memory get all whacked out of sorts and it can take weeks of DD driving to reset. Removing power will reset those values to factory neutral ASAP.

yeah i did reset it when i cleaned my maf and changed out the air filter. it looks like my mileage has gone up a bit but it is hard to tell because i went playing mud yesterday and we just got over a foot of snow today (summer yesterday, dead of winter today....) so i am spending alot of time in 4wd.

i am up to about 18mpg now but this wasn't a very economical tank of gas so i may have gained 1 or 2 more. thanks for everyone's insight. 235/75/15 goodyear wrangler territory's tires and a 2 inch coil spacer lift to come this weekend or next so i can expect to drop from that i assume