Astra AH 2008 very thirsty

[sloanetce]

Hi guys I have just bought a Astra SW . I am not really impressed as it uses more than 12l/100km of petrol. And the engine is not as smooth as I was expected from an European car.
I have changed the oil and filter even weren't due, airfilter is quite new and clean.
What is a normal consumption in the city?
How can I check if everything is ok? Is there any kind of computer test which will tell me if the engine is working in good parameters or if is something wrong? I don't want to spend big money.
Thanks

[guy 27]

lots of things come into factor with fuel economy.
such as fuel type, sensors, but most importantly driving style.

there is an ecu which can show if there are any fault codes. do a search for pedal test on the forum. :)

if the engine isn't running smooth it could possibly be that the timing is out by one tooth.

[sloanetce]

Thx for the fast response.
I did the pedal test. It came with ECN00000.
Shall I understand that everything is ok? Is there any possibility that the ECU will miss out some information which can be vital.
I am going to a long trip (2500km) with my family and I would like to know if I can go with this car or I take my old Nissan which has never broken down.

[guy 27]

if thats what came up then there are no fault codes in the system and all sensors are running within the parameters.
if you don't feel the car is right theres very little we can do via web without seeing the car first hand. thats the beauty of the fault codes when they do appear as it makes diagnosing issues nearly perfect every time.

What engine model is the car? also what type of fuel do you use in it?

[sloanetce]

It is a Z18XER and I use 91 Unleaded.
There is a note on the petrol lid that the engine will work even with E10 not that I want to use.

[dutchy]

don't know how many k's you've driven it yourself but after an ecu reset, the first 250 k's or so the car uses more fuel than normal. Check the plugs too and see if they aren't foul.

[sloanetce]

Thanks. I'll check the plugs.
No recent ECU reset . Actually I have just done it tonight.

[adam_92]

Also from personal experience running the car on 91 will make it feel like its not running its best. Try 3 tanks of 98 premium so the system is flushed through. Costs a couple of dollars per tank more but the car will have better economy and will run a lot smoother...

[XLR87N]

My Vxr gets 650kms to a tank and my sister in-laws 2007 AH gets closer to 700. We both run 98 and average in the 9~L/100 range. Something is up. What oil did you use?

[dizzydumb]

Oh my... 12L/100km from a Z18 is def worrying mate. My vxr is averaging 11L/100km, and that's with me booting it every now and then.

[chrissn89]

My flat mates AH 2007 average is 6.8ltr/100km mostly highway. Never seen it into the 9's before. His is a manual.

[J]

Do the trips involve lots of stop start traffic?
How long is each trip approximately?
How many % of the time does the car stay in the lower gears (a lighter foot in standing starts, and not putting the gearbox into Sports Mode, can perhaps prevent this)?
What tyres are on the car?
What are the tyre pressures?
How choked up with carbon are the throttle bodies and the EGR valve (just guessing this might be the issue)?

As a reference point: our 2001 Corsa C (aka Barina XC) 1.4 auto does low 9L/100km when driven only by my sister on short trips, which is similar to my Turbo Astra...

[sloanetce]

As I remember I did just over 400Km

[sloanetce]

We use the car for short distance trips most of them less than 7km some of them about 2km (going to work and back).
When I went on motorway about 120km out of 400km the average was 10l/100km.
What is the EGR valve?
Tyres 32psi on front , 32 psi back (as I remember)
The tyres are normal size for the car nothing fancy (Bridgestone).

[sloanetce]

I would be happy with around 10L/100km and with a different sound coming from the engine.
Today, I had another Astra, identical with mine, and the engine had a different noise more like a would like to hear.
I will take to a mechanic. Shall I try Holden or better stick with a mechanic which I trust.
Is Holden going to do a thorough check? Is it going to be better than a local mechanic having a tester?
Is it any chance that is a tune in problem?

[sooty]

Go to a trusted mechanic or a place like ultratune etc, not Holden.

Your exceedingly short trips will be responsible for your economy, at only 2km long or so, you'll barely be getting out of closed loop fuelling.

[poita]

Agree with sooty, the short stop start with be the main issue with your economy.

I'm barely getting 450km out of my 1.8l Corsa as I do no more than 5km trips from home to work.

On the highway it gets over 700km

[J]

And while it is being inspected by the mechanic, might as well check how dirty are the throttle body and the EGR valve anyway, as they are definitely worth cleaning, and should make the engine run smoother and more efficiently. You can even DIY! Do a search...there might be a thread here somewhere or on other forums.

Let us know how you go!

[rjastra]

Is it an automatic? If so, do you leave it normal mode or do you put it in (S)port mode that locks out 4th?

Try the car on PULP (95RON). Probably the best compromise between price and performance.

[benzino]

when was the last time (if ever) the fuel filter was changed? If it hasn't been a while, change it and put a bottle of injector cleaner through the tank

[gravy258]

Z18XER's run on 95ron petrol minimum, thats what it says on the filler cap door on mine. If you run it on 91 it will run sh#thouse.

I also took the screens out of the VVTI actuators, that seemed to help.

It hesitates a bit from cold but is just OK otherwise.

Mines a 2008 manual it does about 9.2L to 100km's. And thats doing 7km commutes, never any distance.

[sloanetce]

Thanks guys
I will be busy doing all things. I will start with 2 tanks 98RON petrol hopefully it cleans the injectors and the engine?
That will take about 4-5 weeks. If no improvement I will take to a mechanic for more testing.
I will let you know how things are going. About the fuel filter I do not know as the last Holden authorized service was at 30000km and after that some local mechanics.
I bought the car last month from auction so I have not too much information about the car just the service book.

[sloanetce]

I don't know. Do you know what the maintenance schedule requires?
I couldn't find it in my service books.

[sloanetce]

It is in normal mode.

[gravy258]

you might want to change the oil if you bought it at auction. If it doesn't have full synthetic in it that won't help.

[sloanetce]

I have just changed the oil and filter with mobil 5w-30 semi synthetic. Why do you think that it will not help unless it is fully synthetic?

[guy 27]

you might want to change the oil if you bought it at auction. If it doesn't have full synthetic in it that won't help.

don't see any real point in running a full syn oil in a stock road car. semi syn is ideal.

[benzino]

don't see any real point in running a full syn oil in a stock road car. semi syn is ideal.

+1
hell, the GM factory oil for the SRI turbo is a semi-synth

[gravy258]

+1
hell, the GM factory oil for the SRI turbo is a semi-synth

GM worldwide factory oil is Dexos 2, which is 5w-30 full syn. Made for Holden by fuchs. (or Dexos 1 5w-30 full syn for commodores)

If this guy is looking to increase fuel economy everthing has to be right. From the oil's to the tyre pressures.

AH Astra's state in the owners manual 5w30 full syn.

[sloanetce]

I have just returned from a 2300km trip. The car has just responded perfectly to all road conditions.
It has used 6.72L/100km using petrol 95RON and 7.9L/100km using 91RON which is not bad considering the car was full load with 4 passengers and lots of luggages.
So I believe that is nothing wrong with the car and the problem is that I drive the car for such short distances.
THANKS guys for your input. Hopefully this discussion will be useful to other Opel enthusiastic owners.