Why is my car drinking petrol??

Question

I have a Vauxhall Vectra 1598cc ... 1.6ltr engine. I drove it for 30 miles and have already used about 10 ltrs. of petrol. Now this will definitely cause a dent on my pocket. Any clue why is it literally drinking petrol?

I do not smell petrol though, so I doubt its a leak.

Also.. I drive at 60-70 miles/hour. The tyres are inflated to the specifications- not more, not less. I think it might be the filter then... since almost everyone is saying so...

That is it... I do have that orange light lit. Infact just this morning I noticed that it just doesnt go off and it was indeed bothering me. Thanks Mick..

Answer 1

Hi, I had a similar problem with my car recently. I was getting 10mpg and I managed to sort it out my self. The Vectra 1.6 has a modern car, and has an engine equiped with OBD2 (On Board Diagnostics). This diagnostic system is part of the ECU and enables you engine to run efficiently buy monitoring engine conditions to minimise the amount of fuel needed at any given time. If any of the sensors it relies on go wrong, this can effect how your engine runs and its fuel ecconomy.

The first thing you should check is your coolant temperature sensor. This sensor costs less than £20 and is easy to change. It's job is to tell the engine management system how hot the engine is. If the engine is cold, more fuel is required to prevent the engine from stalling. If this sensor is faulty, it could be telling the computer that the engine is perpetually cold, pumping in more fuel than necessary all the time.

The second thing you should have checked it your LAMBDA probe. This sensor monitors the exhaust gases. It tells the engine computer wether the fuel mixture is too rich or too lean and adjust it accordingly. If this sensor is faulty it could tell the engine that the fuel mix is too lean and cause it to burn more fuel.

Another thing to check is the airflow mass meter. This sensor if found close to your air intake and monitors the amount of air going into the engine. Anagin, if this meter is giving false information to your ECU, the result could be lower fuel mileage.

A tell tale sign that one of these sensors could be at fault is whether or not your engine idles smoothly. If they idle speed of your engine is erratic, then one of these sensors is likely to be the culprit.

Otherthings you might want to check include your spark plugs and leads. They should be changed every 40,000 miles approx. Also your fuel injectors. They should be cleaned every 60,000 miles.

My MPG is back up to 45mpg after changing my coolant temp sensor.

It shouldnt be a fuel leak, as you would have the assotiated smell if you were loosing that much fuel.

I hope that this has helped you

Regards A.



Additional:

The orange light is part of the OBD system that I have mensioned. Without seeing the car, it would be impossible to tell you which of the sensors has gone wrong. I would take it to a garage, but make sure that they are equipped to diagnose OBD problems. I will also add that it is very unlikely to be the airfilter causing your problem.

Answer 2

Forgive me, I'm not too good at metric conversions, but it's apparent that you're using alot of fuel.

A 1.6 liter engine would of course be a 4 cylinder engine. You should be getting around 30+ miles per gallon ( Please do the math, I'm terrible with the metric system! ).

If the vehicle has been run for some time without having an oil change, that's going to consume alot of fuel. Also, if the motor is having problems with "breathing", you might try a different air filter than what you have now. OR, the stock air filter may be clogged and dirty. If the motor has a PCV valve, and it's clogged or dirty, that will consume fuel.

Another thing to consider is the condition of the cylinders themselves. If this is a high mileage vehicle, you could have worn piston rings, causing "blow-by", meaning that gasoline is blowing past the piston rings and the cylinder wall, and the gasoline is not burning efficiently.

Another thing to check.... if the engine is carbureted, then there is possibility that there is a problem with your carburetor. Even a gasket leak. If it is fuel injected, then you might want to have your injectors checked out by a mechanic. Also, don't rule out a leak in your gas tank or fuel lines. Hey, don't laugh, it happens!

At any rate, a motor of that size should not be guzzling gasoline, and it should be checked out as soon as you can.

Answer 3

Actually i had a similar problem in a 1300 Vauxhall Astra, it was using petrol like a 2 litre. Eventually whilst checking out an entirely unrelated matter my mechanic found a very small hole in the fuel pipe just near the fuel pump. This was causing an almost imperceptible leak when the engine was idling but was obviously pumping well when the engine was under load. As i say it was only by chance that he found it and thus i would suggest that you check the entire fuel system including the pipe work. Incidentally the hole was on the blind side of the pipe which was why it was so hard to trace.

Answer 4

Have you ever had an orange light on the dash showing if so its your eng managment system telling you it has a fault.The most common fault with the Vectra is the lambda sensor not working correctly this will give you an over rich mixture which causes poor fuel consumption.Also the mass airflow meter can cause this problem.You need to get it booked in to a garage that has diagnostic kit for Vauxalls.

Answer 5

there are several potential reasons - but as it's such a huge amount my first guess would be a leak - do you get a strong smell of petrol when you get out of the car or when you start it? check under the bonnet and see if you can see it coming out anywhere - should be quite easy to spot as it'd cause a clean bit! Then it might be as easy as replacing, or even just reattaching a piece of hose.

If it's not that take it to a mechanic - hopefully all it will need it adjustment to either the carburetor, I can't think of anything too expensive that'd cause this

Answer 6

Have you changed the air filter? if this is blocked then it's like the car is running on choke all the time. Put the back of your hand near the tailpipe with the engine running, if the fumes feel hot then the engine is burning too much petrol, if it feels cold it is normal and you have a petrol leak.

Answer 7

Well my friend there can be a few wrongs settings in your car engine,can be the carburetor [ciclers too big],air intake too much [air filter too big],can be the timing [too much advanced],can be the tyres low on air,a very soft suspencion sistem that makes the car heavier,and also can be how much you press the acelerator because many people complaint about the use of too much petrol but this is because they like to race all others cars and allways want to go first than everybody.

Answer 8

Automatic cars are slightly heavier on fuel than manual cars due to the slippage between the fluid clutch in the gear box. If there is a substantial difference in consumption and you are comparing like for like (Same car, same engine) then you need to check out the following:- 1) Gear box oil level. 2) Service record. 3) Kick down setting. 4) Tyre Pressure.

Answer 9

if u haven't serviced the car in a while then have it serviced

anything from blocked air filters, dirty engine and engine oil filter to dirty fuel filter could responsible for this

while u r at it have the plugs changed as well

Answer 10

It could be the Lamda sensor which will make it run very rich, a garage diagnostic check should pin point the problem.