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The mkiv Supra Owners Club

fuel!!


Andrew_sup

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hey guys i got a fueling problem, which is im using way to much fuel i can do a journey of 14 miles and it will cost a £5 which is nutts even for a 3.0ltr and its only a n/a auto. can notice a slight smell of petrol when i get out after a good blast and it idles at about 500-600 rpm. will a simple service cure this? and what mpg should i expect.

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There's an FAQ on how to check your O2 sensors.

 

Click HERE.

 

I'd like to add to what they say there though.

 

If you're not getting the readings mentioned or want to confirm the operation of the O2 sensors, rev the engine taking it up to over 2k revs sharply and then let the throttle off quickly whilst looking at the voltmeter. As the ECU adjusts the fuelling for the sudden changes in load you should see the voltage vary up and down between 0v and close to 1v. If this doesn't happen, you'll probably see only a few millivolts or nothing at all. In this case, the sensor is probably knackered and the ECU isn't getting any signals from it.

 

When the ECU receives low voltage (tending towards zero) from the O2 sensor, it interprets this as running lean and will try to add more fuel. In the case of a knackered O2 sensor, it will keep adding fuel, waiting for the voltage returned from the sensor to climb. When it doesn't climb to a normal level, the ECU never backs off the fuelling and the car runs very rich.

 

Hope this helps. Let us know how you get on.

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