A question on VZ O2 readings

[Charlescrown]

I looked at a VZ Alloytech V6 today. The complaint poor fuel consumption (uses more than his old Ecotech). The car consistently gets in the high 9's on trips. On the live data it shows both front O2 sensors running hard around 1 volt and not getting any lower. The rear wideband sensors are reasonably steady around 500-560mv which to me indicates 14.7 A/F ratio. The short and long term fuel trims are around 1 to 3% and it's in closed loop. Opinions please. Are these reading normal or should the front O2 sensors be much more active and swing all over the place? The car has dome 130,000km and he has continually complained about high fuel consumption since he bought it at around 80,000km.

[Holden202T]

my Alloytec was a SV6 (190kw) with 5 speed auto.....

the front O2's in it was actually LSU 4.2's are you sure they are reading volts and not Lambda ? cause I know mine showed in HPT as lambda readings....

as far as fuel economy went, I'd possibly see 8's on a long freeway type of trip, but it was also rare that I wasn't fully loaded for holidays or towing a trailer ......

but also just day to day work trip it averaged about 10-11L/100km, that's about 50-50 town and highway, and im a bit of a lead foot

[HQ355]

My wife's vz sv6 has done a best of 6.7 L/100 on a trip but normaly on a long trip it will be in the 7's. My VE sidi is in the 7's on a trip so I'd say it's using a bit too much fuel

[Jayme]

ive heard a lot of alloytec owners complaining about excessive fuel consumption...
my alloytec 190 AWD adventra does about the same as my LS1 sedan... 12.5 ish around town, high 9s on freeway. should be able to do better than that in a sedan.

my narrowbands swing about, the widebands I read in lambda.

[Charlescrown]

OK that explains it. I didn't look close enough at the time to see the front ones but Lambda is sensible for the reading I was getting and looking at the service notes the front is indeed a Bosch wideband and would then put out 0-5 volts and if it were 1 volt it would be extremely lean. So my assumption is everything is fine. Thanks for the input. This bloke has kept a diary record of every bit of fuel he has put in his cars for the last 20 years that I know of and analyses every tankful. Crazy.

[HQ355]

Everyone needs a hobby ! Lucky he dosnt have a V8 lol

[Holden202T]

yeah that's dedication

I know I make sure I reset my L/100km counter everytime I fill up but that's just more boredom I think

[Dylan]

ive heard a lot of alloytec owners complaining about excessive fuel consumption...
my alloytec 190 AWD adventra does about the same as my LS1 sedan... 12.5 ish around town, high 9s on freeway. should be able to do better than that in a sedan.

my narrowbands swing about, the widebands I read in lambda.

12.5 gee I just checked mine this arvo it's 16.2 and I drive it very easy bevause I know it's a thirsty bugger.
It's an 05 6 speed crewman. Not sure if it's in need of a major service or a tune surely it's not meant to be that heavy on juice. And it has bugger all go too. Really lacks power should put my wideband on it one day to see.

[Charlescrown]

I just had a thought. He mostly does country runs but carries a load of tools each time so I am happy with the way its running. I did the plugs last time at 115,000kms and like always with modern cars they looked like new. Air filter is clean and as I said short and wide term fuel trims are 1-3% so He should sit back and enjoy the car (or by a fuel cell car 1L/100kms but how much does Hydrogen cost?).

[vlad01]

Worth checking tyre pressure. that effects economy a lot.