Caprice fuel economy worst I’ve ever seen

[POVRTY]

Hi people. I’ve got myself a early wm caprice L98. 06 or 07. I’ve had L98’s before however nothing as thirsty as this. I’ve always done my own work on cars if a can and I want to dig a little deeper into this. I’m only getting around 300kms or less to a tank and the car smells. Like I burnt fuel fumes. It make your eyes water. It reminds me of my old cammed ls1 only thirstier. Before I go pulling it apart is there anything I should go straight to. I was going to start with o2 sensors? Can they be tested at home or do I just replace them and hope for the best? the car is regularly serviced and i would happily take the advise who knows or perhaps has experienced something similar. Thanks

 

[Asmodai78]

Check the fuel tank for leaks, is the fuel smell stronger in the engine bay or at the back of the car?

 

[POVRTY]

It’s a rich exhaust smell coming from the exhaust. I can’t even idle at the traffic lights with the windows down. It stinks

 

[lout]

is this stock or been "tuned"
use engineering mode to see actual fuel usage and post result
http://www.autoinstruct.com.au/manufacturer/holden/ve-commodore/accessing-engineering-mode/

 

[POVRTY]

The car only gives an instant fuel reading. And at idle is floating between 1.7-2.3L/h
Leaving the lights or just cruising can give massive reading anything upto 99L/h. I don’t drive it like a race car I normally have 3kids in it with me or the wife drives it. I work away every second week. As far as I know the car is stock.

 

[tfabio]

If it's constantly running rich then it might be the MAF sensor.

 

[_R_J_K_]

Start with o2 sensors and go from there. They're typically the most common issues with fuel consumption.

 

[POVRTY]

Righto. Does anyone have any tips on how to test the old o2 sensors? Can they be tested with a multi meter? The only other way I can think of is to un plug them individually and take it for a drive while keeping an eye on my fuel consumption? That kind sounds like the long way around things though.

 

[Deuce]

O2 sensors are a serviceable item so just replace.
How many kms on the car?
I would also check/replace airfilter. Clean MAF. Check & replace spark plugs noting anything strange on old ones and investigating further.
If it feels underpowered then also check/bin/gut/replace cats.

 

[VT&VX]

Why hasn't anyone told you to get an eBay bluetooth ELM diagnostic.

Since you are going to replace the O2 sensors, try replacing them one at a time, and write on them with a marker. Initials for .. eg driver side, passenger side.

So when you throw them in the tool box, you can know which one was the dud, or both are still good if it makes no difference.