Thursday, May 20, 2021 at 09:35
Woodsy
If a 4.8 normally runs on 91 and timed to do so then all ok. With the "Outback Experience" of using Opal which is said to be also 91 or better, the
fuel which you received may have been stored for a while and much of the most volatile molecules had left the scene through evaporation in Aussie heat. That leaves lower volatile fractions of
fuel to make up the fluid
fuel you received. When used, MORE
fuel has to be injected to make up the energy/power required to drive the vehicle forward. That may explain why very high
fuel use. If there was any contamination in the
fuel the OXY sensor may have received a blast of rubbish and not sensed OXYGEN levels very
well. Most times they then cause the ECU to overfuel until the sensor is replaced or the crap is burnt off the sensor by long hot running. Just a thought.
Might also explain why some of the community folk think they have enough
fuel to travel to see mates and find they run out somewhere and search parties then become involved.
If
fuel has deteriorated through evaporation the
fuel burning rate will be slower when ignited by the plug. That means the
fuel is still burning when leaving the the cylinder, a bit like late spark timing, and so causes overheating and engine failures if extreme or driven hard while it is happening. Burns exhaust valves!
Any
fuel which is still burning upon exit from cylinder is total lost
fuel efficiency as that portion contributes nothing to gas expansion in the cylinder to push pistons. If the burn hasn't happened by 2/3 of downward piston travel, then in the last 1/3 or beyond nothing much is gained. All
fuel should be burnt before exhaust valve opens. Best if it is!
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