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Discussion Starter · #1 ·
Hello everybody,

My 1.7 CDTi uses an excessive amount of fuel. Combined around 34 miles to the gallon, extra urban, if I'm lucky, around 41 miles to the gallon. Seems to get worse by the day.

I have changed the MAF sensor twice already, Both front and rear brakes were stuck so replaced everything, did an overhaul on the front calipers as well, glutch has been changed (twice). Both catalysts have been removed.

Before I start to pull the engine apart, what more could be the cause for this fuel consumption? I hope te find the solution to this problem with your help as this is my daily. Starting to get a very expensive daily馃槄

Hope to hear from you guys..

Cheers.
 

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Discussion Starter · #3 ·
fuel losses? turbo status? Has the distribution been? intake manifold pressure sensor?
Had a proper check today:

no fuel leak,
took the pipe between induction manifold and throttlebody off, pretty clean.
Took the map sensor out en cleaned it.
The turbo whistles quite a bit, but got rood not to worry about that.
Not sure what you mean with how the distribution's been.

I'll fill her up tomorrow and keep an eye on the fuel consumption the next days to see if the cleaned map sensor has had any positive outcome.
 

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If the distribution is in phase, it is well drained, when do you say a lot of consumption in how many liters?
 

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That's the best thing to do, to begin with. Fill it up and set the trip meter to zero, drive it a bit (preferably in similar road conditions such as urban) then fill back up again to compare litres required versus km driven. You could do the same with a long highway drive. This will give you accurate figures to work with. Manufacturer claims always look more economical than reality. Your 41mpg is low, but not catastrophically low. My 1.7 DTi (not as clever delivering fuel as the CDTi) usually does 44mpg driving through France and Spain, mostly 100-110 km/h on autoroutes/vias but sometimes 80 km/h roads and some 50 km/h towns etc, particularly in France where non-toll roads are not very good.

I had a look at the Honest John website for reader's real-life mpg for the Astra H and Astravan 1.7 CDTi (no Corsa info) and the average was 45-48 mpg across all road types and driving styles.
 

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Discussion Starter · #6 ·
If the distribution is in phase, it is well drained, when do you say a lot of consumption in how many liters?
The average consumption is 1 liter diesel on 8.5 miles. Long rides around 1 liter per 11 miles.. nu former Corsa C Z17DTH did 1 liter on 14 miles, with bad injectors and a nearly dead glutch.

That's the best thing to do, to begin with. Fill it up and set the trip meter to zero, drive it a bit (preferably in similar road conditions such as urban) then fill back up again to compare litres required versus km driven. You could do the same with a long highway drive. This will give you accurate figures to work with. Manufacturer claims always look more economical than reality. Your 41mpg is low, but not catastrophically low. My 1.7 DTi (not as clever delivering fuel as the CDTi) usually does 44mpg driving through France and Spain, mostly 100-110 km/h on autoroutes/vias but sometimes 80 km/h roads and some 50 km/h towns etc, particularly in France where non-toll roads are not very good.

I had a look at the Honest John website for reader's real-life mpg for the Astra H and Astravan 1.7 CDTi (no Corsa info) and the average was 45-48 mpg across all road types and driving styles.
I have a long trip tomorrow night, so i'm going to keep an eye one the diesel consumption. But IT seems to me that I need to get my Nova 1.5 TD back in action. That one does around 4 liter of diesel at 62 miles/100km. A lot cheaper than this peace of scrapmetal馃槀
 

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Let's see, that is not consumption for that engine, it has to be throwing fuel in buckets on the road, or you have the exhaust and the black defense as if you were wearing a repro, or you have some problem with the fuel intake and return, because So much consumption in the combustion chamber of a 1.7 is impossible due to the air fuel ratio, the only one that you have 20 tires and go foot to foot all day, and I don't even think so much consumption, so first pso check losses and turbo geometry


Basically because the previous one, which is DTI from 75 to what the car gives, does not go from 7.5 to 100km
 

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Discussion Starter · #8 ·
Let's see, that is not consumption for that engine, it has to be throwing fuel in buckets on the road, or you have the exhaust and the black defense as if you were wearing a repro, or you have some problem with the fuel intake and return, because So much consumption in the combustion chamber of a 1.7 is impossible due to the air fuel ratio, the only one that you have 20 tires and go foot to foot all day, and I don't even think so much consumption, so first pso check losses and turbo geometry


Basically because the previous one, which is DTI from 75 to what the car gives, does not go from 7.5 to 100km
I am having my doubts about the turbo. And where I'm still thinking about is both catalystic converters being removed. Maybe it needs at least one of the two..
 

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Discussion Starter · #9 ·
Took the diesel for a proper ride, 590 km (366 miles) on 38 liter diesel. Roughly 1 liter diesel per 15.35 km/9.5 miles.

The last few days I keep seeing plumes of smoke as I drive away from trafficlights and when the car is stationary and the engine is running, there is a mix of diesel fumes and exhaust fumes around the car. Yet, we still haven't found a diesel leak anywhere..

Had a spare turbo checked today. The spare turbo is decent, al will be changing the turbo. Still no I dea about what causes the excessive consumption..

So, does anybody have any suggestion?
 

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Discussion Starter · #11 ·
What we have checked up till now seems to be okay. Nothing out of the ordinary. But honestly, i have nothing to compare the data from my car with.
 

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I say, it is the only thing that occurs to me to be able to help you now, see the values, if you say that mechanically everything is fine, the ideas are already running out
 
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