Consuming too much fuel

Hello,

I would recommend doing a tune up on your vehicle. Change spark plugs and wires[if applicable], change air and fuel filters. The spark plugs are big thing to change here and make sure that the gap is where it should be. Ask them what the gap should be at the auto parts store where you purchase them, Please get back to us with how everything turns out. I hope that this helps you out.

Thanks,
Alex
2CarPros

Hello again,

Sorry, I forgot to add this last time, so here is a guide on how to pull the Direct Trouble Code[DTC] from your vehicle's Data Link Connector[DLC] if your MIL or 'check engine' lamp is illuminated:

https://www.2carpros.com/articles/checking-a-service-engine-soon-or-check-engine-light-on-or-flashing

Please get back to us and we can go from there.

Thanks,
Alex
2CarPros

Hello again,

Okay, so you should never clean an O2 sensor. They are very fragile and can get poisoned very easily. For example, gasoline, oil, coolant, dirt, grease, any of these and a whole list of other things can poison an O2 sensor causing it to malfunction. Is your vehicle's MIL illuminated? If this was a problem with an O2 sensor sending a signal to your vehicle's Power-train Control Module[PCM] or "computer", it would set a Direct Trouble Code[DTC] and illuminate the MIL. Please get back to us and we can go from there.

Thanks,
Alex
2CarPros

Hello again,

Okay, well Honda of North America made it plainly clear to myself when I went through their university not to poison an oxygen sensor and I had three separate modules explaining what not to do, and cleaning them was at the top of list. I don't mean to sound confrontational, I am just trying to pass along what Honda taught me about oxygen sensors. The real way to test an oxygen sensor is to hook up a scan tool with the ability to show live data, and check the voltage values that your oxygen sensor is outputting in closed loop operation. Also being able to look at your vehicle's short term fuel trim is a very useful tool here. If you don't have access to a code reader with this ability, maybe your mechanic that you are working with would have this capability so you guys can check the oxygen sensors operation and make sure that it is not biased lean or rich. Please get back to us with what you find out and we can go from there.

Thanks,
Alex
2CarPros

Hello again,

Okay, so the O2 sensors are good, and you have done a tune up, so the only thing left in the engine management system that could be bad would be the fuel map in the Power-train Control Module [PCM] or "computer". You might want to inspect the electrical connectors going to your vehicle's PCM and ensure that they are tightly connected with no corrosion anywhere. Also you should check all of your vehicle's grounds and ensure that they are clean, tight, corrosion free, and making metal to metal connections.I would give you the wiring diagrams or the location of the PCM, but your vehicle is not in the United States market, so it is not in our reference guide. Please get back to us with what you are able to find out.

Thanks,
Alex
2CarPros

Please let us know what you find. We are interested to see what it is.

One item I don't see mentioned, check the vehicles fuel pressure regulator and the actual fuel pressure. The regulators can fail internally and most are connected to the vacuum system which can give you an uncontrolled fuel source that the engines systems wont try to compensate for. Another issue could be high fuel pressure from a bad regulator or pump. That can cause the injector to spray in a larger amount of fuel that the system thinks it's getting. Depending on how advanced the computer is it may or may not try to compensate for it depending on how much extra it sends. To check that closer you could use a scan tool to look at the actual fuel trims as the engine is running. Ideally you would want to see them at very close to zero on both long and short term trims. If however you see the long term or both showing a negative number, there is extra fuel getting in somewhere.
Also check what the coolant temperature sensor is showing, and compare that with other temperature sensors. If the coolant is fully warmed up but the ECM sees a very low temperature it could be running in a heavy enrichment mapping thinking it is in a very cold area, that can cause a lot of fuel use, but the computer wouldn't see anything was wrong.

Have there been any changes in your driving routine like more air conditioning usage or more stop and go traffic than before? Even something like changing fuel stations can cause fuel consumption differences. I don't know if your country adds ethanol to the fuel or not, I think they do. If they changed the percentage or if you simply got a bad tankful it could cause problems.

Hmm if the problem started after the pump change I would check the pressures. There are many times that a pump can look just like another but they are for different applications and have different specifications. So you could have a pump that puts out a higher pressure.