Was doing average 15l / 100km but now doing 21l / 100km

[EvilDaifu]

Hey Guys,

 

Got a question about fuel consumption.  If I was doing 15l / 100km on average previously and now suddenly finding I'm doing 21 / 100km on average - what are possible causes if my driving patterns have not changed?  FG F6 with edit.  When I change to instaneous view of fuel usage - I see it shoot up to 75l / 100km occasionally but I got to admit I've never really monitiored instaneous fuel use before so would not know if that was normal or not.

 

I have an XCAL3 edit.  I'm planning on reflashing the custom tune back in tonight over the existing tune but am pretty sure nobody's touched the edit.  Maybe I should drop it back to stock to see if fuel consumptions is still high?

 

K&N pod air filter in a SS Growler induction setup is dirty but from what I've seen that would only contribute to a 10% increase in fuel consumption if it was dirty.  I'm planning on cleaning that tonight.

 

One other thing I'm doing lately is only filling up to about 1/3 tank because farrken fuel prices so high.  I let it drain down to close to empty.  Do you think that's fooling the trip computer somehow?  I have normally previously only ran with full tanks and never let it drop below 1/4 tank.

 

Could it be some fuel filters getting clogged up cos I let the tank drain down to much?  I did have the oil filter changed out in recent service though.

 

Open to ideas.

 

Thanks.

[Rab]

Only real way to test is to fill tanks, take note of how much fuel went in for how many km's over quite a number of tanks.

 

If it's only over a shorter distance then any variables are going to be exaggerated. (e.g. 6 uphill, 4 downhill trips on one record vs 6 downhill, 4 uphill on the next one - all due to which part of the journey you reset the counter)

 

I don't think??? the levels in the fuel tank come into the consumption calculations? Just the distance to empty (which is based on the level of fuel and the recent consumption)

[masda74]

the fuel log app on android works a treat. each time I fill her up or even do top ups(mark it as top up when doing entry) will calculate real world fuel consumption.

not sure if you use an android up or iOS.

[Rab]

I dare say your consumption on Friday night/Saturday morning will vary quite a bit from Saturday arvo, Sunday, Monday

[EvilDaifu]

So I took the K&N pod air filter out and I'm part way through cleaning it with K&N filter cleaning products.  Just letting the pod dry over night.  

 

But I can't believe it was the cause of the huge change in fuel consumption - but who knows - worth a try cleaning it anyways.  What I suspect is more like what I think Rab was saying - because I had changed my pattern of filling up - instead of filling completely to the brim - I only went 1/3 to 1/2 tank - its somehow mucked up the fuel consumption calculations.  I can't believe instantaneous can goto 99.9l/100km but that's what I was seeing at times on the drive home from work today.  So am hoping its got something to do with my changed filling habit and with the clogged up air filter.  Had bugs and stuff in it from Tassie cruise and prolly had not been cleaned for ages - possible ever since the SS Growler was installed which is when I don't know.  

 

Oh - I also filled up completely tonight and it shows Range 380 km whereas previous it would show about 405 km.  But I guess that is directly related to the current average being 21l/100km. 

 

I'll try flashing my edit back in tomorrow as well.  

 

And I'll see what the fuel economy ends up when I drive to Adelaide.  If it is north of 9.9l/100km which is what I was doing in Tassie after a long drive - then I suspect something is quite wrong with the engine.

[Box stock T.]

O2 sensor can be a bit of a calprit.

[EvilDaifu]

Where's the O2 sense and how are the ways it can get damaged?  Thanks mate.

[Box stock T.]

On a b series it's on the standard dump pipe.

On the F series it has two . One before the cat and one after the cat.

[EvilDaifu]

Ah okay.  So if its the cause then maybe one ot both got damaged somehow whilst driving around?

 

Anyway - I did a search and Big Kays was saying he could smell fuel when idling and thats the case for me.  But my tunes have always smelled high on fuel - even in my BA.  So its not something I would pick up easily. Thanks.

[Box stock T.]

I would of thought the fact that you are practically running tune only with a couple of intake mods it points to something like the O2 sensor or even intake manifold leak maybe...

People like Jet or Luke( ralphy ) would narrow it down a bit more for ya..

Mine fouled due to crap injectors and a rich fuel tune installed before I took it to Jetters..