HELP! Jimny Burning Fuel - 12L/100km

Hi Guys,

My Jimny 2011 has recently begun using loads of fuel. The exhaust is black with soot and I can smell the fumes are rich with fuel.

I have replaced the spark plugs, air filters etc. Nothing seems to be mechanically broken.

Last year November my catalytic converters gave out and I replaced them with a quality free-flow exhaust. Everything was running fine but I started noticing about a two month back that my fuel economy became high. I'm averaging 12L/100. When we replaced it I didn't chip it or have any modification to fix the check engine light.

Does anyone have any suggestions on what to do?

I'd start by looking at the pre-cat lambda sensor, this controls the fueling.


If it stinks of fuel then it must be miles out, and I'd expect the engine light to be on, as it must have hit the end of the fuel trims.

Mind you, a 2011 with no catalyst should have put the light on anyway- has some one been at it and nobbled the post cat sensor with one of those "fixer" pipes? - (actually, I'd start with checking for fault codes, I'm guessing there aren't any?)

If it has been nobbled, and is just running open loop all the time, I'd check fuel pressure, and then for a stuck injector, either mechanically stuck, or an electrical short keeping it open.

Jace wrote: When we replaced it I didn't chip it or have any modification to fix the check engine light.

It's likely to be something caused by the recent changes, as Facade said the Lambda (or lack of?) Is a likely cause. If I am reading your post correctly it appears you do have engine light on, so start by reading any fault codes and address these issues to put the light out.
All the best
Mike

Another possibility comes to mind, the engine temperature sensor. If this is disconnected, or failed the ecu thinks the engine is cold and runs rich- the equivalent of being on choke all the time.