04 ZC Vectra 3.2 Bad Fuel Economy

[marsupial]

I have had this car for 2 months now, there is a bit of a story to tell to get to my question.

Bought the car and the Trip Computer was telling me I was getting between 13-14.5L/100KM which was a bit surprising because all reports I read said 10-12, I am talking City Cycle. Anyway one day when the wife picked me up from the train station I smelt a really strong smell of petrol and I mean REALLy STRONG. I told her to turn the car off and get out. Called out roadside assistance and there was a fuel line just behine the engine if you go from the top, he just clipped it back in with a push, I heard it click. Since then no more fuel smell. I figured this may improve my economy now, WRONG! My fuel economy went to 16-17L/100KM consistantly.

I was very confused. Any way the spanner light came on when I started the car now but went out again. I took the car to a Holden dealer, they put the OP COM thing on and said yep your engine is missing. So they charged me $1000 and replaced the Coil Packs, $800 for the parts and $200 labour, yes I now know Holden Dealers suck. Anyway if I drive the car very gently now and peeve people off behind me I can get the economy down to 15L/100KM which still sucks.

Can anyone suggest to me what can be the issue? Can I use OP COM to adjust fuel mixture or something. I mean the car has only done 80,000 KM's, there is no smoke blowing and it runs quite well otherwise. I am lost to know and so was the dealer. Is this normal economy? if so I would never of bought it to be honest.

Any assistance would be appreciated.

Stephen (Australia)

[KieronGSI]

So the way i work it out is thats 62 miles for 3 gallons of fuel. Which works out at about 20mpg.

I get about 22mpg average but i drive my car quite hard, if i drive like a grandad i can get it up to 30mpg so i would definetly say there is something not quite right with yours.

[poves]

It's a 3.2 , - mine doesn't get much better than that , whether I drive slow or fast.

[KieronGSI]

Really? I find if i stick to 55-65 i get a huuuuuuge difference in economy compared to if i do 90-95.


I have emptied the tank doing 170 miles but on the other hand i have managed 320 miles going slow.

[poves]

That's day to day driving , on a run I can get 220 miles on £40 @ about 80 mph ish

[marsupial]

Really? I find if i stick to 55-65 i get a huuuuuuge difference in economy compared to if i do 90-95.


I have emptied the tank doing 170 miles but on the other hand i have managed 320 miles going slow.

You see that is the issue. we put 50L in the tank the other day and barely got 300KM for that 50L. Both my wife and I have made a concious effort recently to drive slow and careful.

Has anyone played with the OP COM interface? are there any settings I can check assuming I can get one?

[marsupial]

Does anyone have any ideas where I can start?

[Robert Kelley]

The chances are one of the oxygen sensors is at fault. The dealer should be able to test these.

[stevedee3]

On my 2003 manual CDXi I get around 11.5 L/100km if I never let it go above 1500 RPM. Normal city driving gets high 12's and more enthusiasm gets high 14's.

I don't think there's anything electronic that can be adjusted.

I assume your measurements are the average and not the instantaneous fuel consumption?

[CDXI_2003_AUS]

I'm not the lightest foot and I get 10.6 - 10.8 average on mine, mind you, thats with intake, exhaust, premium fuel etc. I'd say do the ecu test stevedee3 posted somewhere in here to read the codes yourself. Where abouts in Melb are you as there are a few of us with the veccy c who would be quite willing to have a look at it for ya.