Corsa utility 1.4 fuel economy/consumption

[frodo]

Hi all

I recently purchased an Opel Corsa Utility 1.4 Club. I have now done just over a 1000km. The dilemma I am faced with is the VERY poor fuel economy. 3 Tanks filled so far. The last 2 I was getting less than 10km/l

I have spoken to an agent service manager who reckons the fuel is automatically managed by a sensor. A closed circuit which can not be tuned. He also reckons the engine is still very tight and still using running in oil. Apparently I can expect it to better after the first oil change on 15,000 km.

I find the poor fuel efficiency a bit hard to swallow.

Does anybody have some recommendations or experience(s) to share?

Regards

H

[blaaislaai]

From my experience, a car needs to be 'run in'

If you still having issues after 15,000km then they should have a look at the ECU or air/fuel mixture.

[Fazda]

When I worked for GM, the 1.4 Corsa was always a gas guzzler, I'm afraid. I never managed to get better than 9.5l/100 and that was doing 80 km to work and back every day...all on freeways. I shudder to think what the consumption would have been if I had been doing more town driving.

[HammerDown]

Bloody ell, that is what I am getting on my 4x4 double cab 2.8 Isuzu. it's got muddies on and I drive with the "hammer down" (sic) all the time....

[BTTB]

I have one Corsa 1.8 Sedan left from the Opels we used to own that my daughter still drives and my father has the Utility.
If there was ever a reason I would never buy a Corsa again it would be for the reason of Fuel Consumption on both the 1.4 and 1.8 models. Always been a mystery to me? Performance too.

My father last year was at his wits end with his 1.8 Corsa Bakkie getting 7/8Km to a litre and the vehicle was still under Warranty. He still joked with the guys at GM that if he wanted this sort of fuel economy he would have bought a V8 Bakkie instead.
To cut a long story short in his instance they removed his computer unit and intake sensor and swapped the parts with an identical Corsa Bakkie they had at the workshop and then it worked like it should. I think he gets in the region of 12 to 14 Km per litre now and it all seems Ok again.
My father who was in the Automotive Industry years ago and knows a little bit about cars although his knowledge is now outdated reckons the problem lays with the sensor unit on the intake manifold. A small little plastic switch looking thing situated (if you are standing in front of the vehicle) at the back against the firewall on top of the manifold.

My experience although I have not changed anything on the car is as follows:
Fiirstly, you have to make sure that you fill the petrol tank up to the top and here you would have to supervise the petrol attendant to do so and then refill your tank the same way later, dividing the kilometres by the number of litres used to get an accurate reading. GM fuel tanks are a pain to refill if you want them filled to the top.
I found that no matter how fast or slow I drove my consumption never varied much, so basically I never tapped off.
I found spark plugs made a difference in performance on the 1.8 and with that goes consumption.
All I know that ever since I had our Corsa I would always be telling the Service Consultants about the performance and consumption. At one service the car would come to life and at another it would be like driving a donkey. I even returned it after one service as the car was dead.
There was even once I had such incredible fuel economy I thought I was driving a UNO. How that happened I cannot say. All I can say is that the car was inconsistent and in my opinion I think it also has something to do with that Intake Sensor and perhaps the computer, but my guess is the computer is sending the right data, it is the mechanical parts/sensors on the vehicle that wear or do not function properly. Perhaps the fuels we use do not lubricate these sensor unit properly. I know by adding small amounts of Two Stroke Oil to your fuel tank can lubricate parts in your engine assembly, but better to ask your Service Manager for advice on that one.

My 2c

[BTTB]

Bloody ell, that is what I am getting on my 4x4 double cab 2.8 Isuzu. it's got muddies on and I drive with the "hammer down" (sic) all the time....

My 300 D-Teq never gets less than 10Km to a litre. I think the guys that hammer these models get about 9.5Km but generally 10Km per litre plus.

[DOOMIE61]

Yeah just wait for the engine to settle, then it should improve..

otherwise tell the sales man you want the 1.7dti

[frodo]

I expected the fuel economy to be better though. Thanks for all the feedback

[Gnome]

The Corsa Utility is heavy on fuel unfortunately. Corsa Utilities fitted with 20XE/C20XE (2L 16valve engine, both the BigBoss and SuperBoss variant) engine use less fuel than the standard 1.4, that's been my experience. That is how terrible that engines consumption is!

I've found that fitting performance mods on a Corsa actually reduces fuel consumption.

I have one Corsa 1.8 Sedan left from the Opels we used to own that my daughter still drives and my father has the Utility.
If there was ever a reason I would never buy a Corsa again it would be for the reason of Fuel Consumption on both the 1.4 and 1.8 models. Always been a mystery to me? Performance too.

It's one of the things I hate GM SA for, the engines used here in the Corsa B/C, namely the Corsa SOHC engines are made in GM's factory in Brazil. They aren't the same engines used in Europe and are largely based on old technology.

Especially the SOHC 1.8 engine is very bad, it's got lower performance and fuel consumption than the 1.6 SOHC engine. Truly terrible engine!

To cut a long story short in his instance they removed his computer unit and intake sensor and swapped the parts with an identical Corsa Bakkie they had at the workshop and then it worked like it should. I think he gets in the region of 12 to 14 Km per litre now and it all seems Ok again.

The reason is that the ECU does store a sort of multiplier value (called the C/O setting), which basically allows the overall mixture to be set. The engine map however cannot be changed, merely updated. Using the latest map may also help.

My father who was in the Automotive Industry years ago and knows a little bit about cars although his knowledge is now outdated reckons the problem lays with the sensor unit on the intake manifold. A small little plastic switch looking thing situated (if you are standing in front of the vehicle) at the back against the firewall on top of the manifold.

Is it green? That would be the manifold absolute pressure sensor. It never comes into direct contact with anything other than air. Basically that sensor detects changes in manifold pressure (manifold pressure comes close to vacuum when the throttle is fully closed and close to atmospheric when the throttle is open). This change in manifold pressure is used to determine the mass of air entering the engine. But because changes in vacuum occur uniformly and at incredible speed, the sensor isn't in contact with anything that could damage it. The sensors are incredibly robust, fitted the many other GM cars (Corsa OPC, Astra OPC, Corsa B,C, some Astra F and G), none of which has this problem.

The problem really is

A) The most obvious: 1.8 engine is a POS, the 1.4 and 1.6 are much better (although not comparable to the UK variant. All the UK engines are DOHC 16v. All the Brazillian variants are SOHC 8v).

B) The ECU used in that car is a local knockoff made by Dupec Electronics Ltd. It's a knock off of the popular Bosch Motronic ECU.

C) The SOHC engines used locally on the Corsa B/C (Utility or otherwise) are based on 1980's engines, these engines never met any type of emissions restrictions. Because South Africa has recently enacted emissions laws these engines are now forced to employ means to meet such emissions. My personal experience is that GM SA have basically created an engine map that specifically meets these emissions but because of this sacrificed both performance and fuel consumption.

All I can say is that the car was inconsistent and in my opinion I think it also has something to do with that Intake Sensor and perhaps the computer, but my guess is the computer is sending the right data, it is the mechanical parts/sensors on the vehicle that wear or do not function properly. Perhaps the fuels we use do not lubricate these sensor unit properly. I know by adding small amounts of Two Stroke Oil to your fuel tank can lubricate parts in your engine assembly, but better to ask your Service Manager for advice on that one.

Nooo. Don't add oil. At all. There is already oil mist being drawn into the intake manifold (by the PVC valve, just about every modern petrol engine uses a PVC valve). That is already bad enough. The only sensor with moving parts on a Corsa is the Throttle Position Sensor and the Idle Control Valve. The rest are passive and the cleaner they are the better (in fact just leave them be). Don't mess with their plugs, don't spray oil in them or their plugs. Just leave them alone. Moisture doesn't get in there and neither should anything else. The sensors are very sensitive, spray anything in their plugs and the readings received by the ECU might become messed up.

If you have sprayed oil in the plugs then that is probably where your problem lies. Just don't mess with any of the engine harness plugs. There is too much theory to explain but you'll do yourself in. Replacing sensors is all fine and dandy but if you are thinking of replacing the manifold absolute pressure sensor or intake air temperature sensor, or cleaning them you'll gain no performance or reduction in fuel consumption. Replace the ECU with another on the other hand may make a difference.

[BTTB]

Phew Gnome. You really know these engines! Thanks for that valuable input.
I will comment tomorrow or the next day, Saturday evening looms and .....

Regards,
BTTB.

[supersunbird]

Now I don't feel so bad about my 1.6 Bantams consumption lol

[wizdumb]

my gf drives a corsa c 1.4, and she gets about 8.5-9l/100km (in town driving only), so i am thinking you are a bit on the heavy consumption side, but engine still needs to loosen a bit

[fs87]

I get 780kms of a tank on my bantam 1.3i so I don't feel to bad, I have a buddy that just got a corsa and it only does 630kms per tank. There is definitely something wrong here. GL needs to fix this...

[snail]

i have the corsa utility 1.4 i base (the new chev model) and i get over 600km on a tank.

[appels]

my mother has the corsa enjoy 1.4 and in town it gets just over the 500km mark on a tank not much in my opinion for a 1.4 but on the open road it gets 15.3km/l very good. my 1.6 golf(citi-rox) gets 14 km/l open road 9-10 km/l town. dads dteq gets 11.6 open road 10.5 km/l town