Crazy fuel consumption

[PieterB]

Hi all,

I've got a 2005 Chev Aveo LS 1500cc manual. It has over 300 000km's on the clock.

The issue started last week where the fuel consumption increased suddenly from the normal 8.0 L/100km to over 16+ L/100km.

It is so bad that if I do a steady 80km/h I could see the fuel gauge visibly dropping.

I could find no evidence of any fuel leaking, dripping or even dust collecting on all the hoses, fuel filter and bottom of fuel tank.

There is a smell of petrol while driving but not a lot.

I've replaced the purge valve out of desperation, so far it seems better but not much.

The engine still perform as usual no loss of power and runs smooth so I made the assumption that it is not the fuel injectors.

Does anyone have an idea as to what else it could be?

Regards

Forgot to mention that there is no engine light or any codes on the scanning tool

[EAD15]

You almost certainly have a fuel leak if you are smelling fuel. Access to the fuel pump and related hoses is typically underneath the rear seat. Remove the seat and inspect that area. I would bet you are leaking from there if you can't find it anywhere else and are smelling fuel inside the vehicle

[PieterB]

This weekend I took a step back and started from scratch.

Firstly I bought a proper OBDII app for my phone and then I took it for a long drive while I monitored the sensors.

While the car was cold all the sensors reported correctly, when the car was at temperature I noticed that the MAP sensor was not changing much and the long term fuel trim was moving from -1.3 to 1.7. When I got home and stop the long term was back to -1.3.

When the long term fuel trim was 1.7 I could see that the amount of fuel being used was way above normal.

So I waited for the engine to cool down and pull the MAP sensor again. It looked clean from the outside but I sprayed break cleaner into it and by magic a piece of something black came out. I put it back again and went for a test drive and problem solved.

Just show how a intermittent MAP sensor can mess everything around and it is difficult to diagnose without a proper logging system.