Murano 2003: Very high fuel consumption

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lolax
Posts: 3
Joined: Sat Jul 30, 2016 8:20 am
Car: Murano 2003

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Hello guys.

I am having a serious headache due to the rate of fuel consumption of my murano 2003. There is something not just right and my Mechanics have not had any success fixing the issue. I have changed the 6 plugs, had the injectors and air flow meter checked and cleaned, the fuel pump has been changed. The best I could get from my car is 6mpg on an average. Can't be more frustrated. My thermostat is functioning.

What could be the issue? Not sure how one of the catalytic converters got stolen by a dubious mechanic. My new mechanic showed me where the cat was removed and sealed off. Could this be the main reason? A machine/computer diagnosis was done by a friend and it found the oxygen sensor faulty. However, My Mech told me the sensors are not actually faulty, just that the missing car converter will make the sensors appear faulty. Please I need a solution. On the verge of loathing this car forever. Please help.


lolax
Posts: 3
Joined: Sat Jul 30, 2016 8:20 am
Car: Murano 2003

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Help!

ArmedAviator
Posts: 526
Joined: Tue Mar 22, 2016 5:28 pm
Car: 2012 M37x
Location: SW Ohio

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Removing the catalytic converter can actually improve economy if done correctly (however is illegal on road-going, registered vehicles). That is assuming the pipe replacing the cat is of adequate size. There are two O2 sensors. One before the car which measures AFR and the second is after the cat which just triggers a CEL code if the cat efficiency drops below a certain point.

You're fuel mileage can suffer significantly I'd the first O2 sensor is faulty or if the pipe replacing the cat is too small or has alot of restriction inside.

It could also be due to other parasitic drags unrelated to the exhaust system. When in neutral on a flat surface, can you roll your car? You may have a stuck caliper if not...... That's plenty of drag.

lolax
Posts: 3
Joined: Sat Jul 30, 2016 8:20 am
Car: Murano 2003

Post

ArmedAviator wrote:Removing the catalytic converter can actually improve economy if done correctly (however is illegal on road-going, registered vehicles). That is assuming the pipe replacing the cat is of adequate size. There are two O2 sensors. One before the car which measures AFR and the second is after the cat which just triggers a CEL code if the cat efficiency drops below a certain point.

You're fuel mileage can suffer significantly I'd the first O2 sensor is faulty or if the pipe replacing the cat is too small or has alot of restriction inside.

It could also be due to other parasitic drags unrelated to the exhaust system. When in neutral on a flat surface, can you roll your car? You may have a stuck caliper if not...... That's plenty of drag.

Thank you very much. However I was thinking otherwise that my car would rather use up more fuel when there's no cat converter. Is there a way to bypass the cat converter and still have a good consumption level?

Not tried to roll the car on neutral. My calipers are not stuck. I've had them checked.


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