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Premium Member
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152 Posts
Discussion Starter #1
My trip computer / MPG is a fair way out. Just wondering if theres any way to get it to recalibrate? I'd have thought letting it drop to near empty when it thinks it has miles left would tell it to adjust, but it doesn't seem to.

Is it possible?
 

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Premium Member
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4,441 Posts
I don't think so, though others will soon correct me if I'm wrong.;)
They never have been that accurate and are meant to be a guide.
I never trusted mine and would never let it read less than about 17 miles to go.
 

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...............Daedalus
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3,687 Posts
Would the inaccurate trip computer have anything to do with the inaccuracy built into the speedo?

Maybe getting it calibrated would back the trip computer more accurate?
 

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Premium Member
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853 Posts
Would the inaccurate trip computer have anything to do with the inaccuracy built into the speedo?

Maybe getting it calibrated would back the trip computer more accurate?
It seems to vary with the engine, the 1.8 was always about 10% optimistic were as the Type R is almost smack on.
 

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Premium Member
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75 Posts
Would the inaccurate trip computer have anything to do with the inaccuracy built into the speedo?

Maybe getting it calibrated would back the trip computer more accurate?
I don't think so. If we are talking about the MPG calculation part of the trip computer, it gets a raw feed of VSS. The speedo is 'inaccurate' because its designed to be, but VSS as fed to engine management and the trip computer will be as accurate as it can be.

MPG calculation is an estimate, I thought mine was pretty good pre remap, but after was over optimistic. Not surprising given that certain figures used in the equation will have changed, AFR being the most likely one.

If we're talking about the fuel measurement part of the trip computer, how many miles left till empty etc, I think its just an inaccurate system used. Doesn't it simply use a rheostat type gauge in the fuel tank for its calculations? The ones Honda use must not be sophisticated enough and be quite basic, not sure any more can expected from a crude measurement device.

At least the fuel gauge gives errors in the right direction, ie there is always more fuel left than expected, better than running out.
 

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Ezermester
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151 Posts
Fuel gauge indication is a calculation from the consumption. When you refuel enough, it reads the actual quantity and then calculates the remaining quantity.
I have a problem since I have LPG installed, the fuel gauge shows as if I am using petrol and then when the quantity decreases about one third of a tank it jump back to the actual value and the cycle start over again.

Andrej
 

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Premium Member
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75 Posts
Fuel gauge indication is a calculation from the consumption. When you refuel enough, it reads the actual quantity and then calculates the remaining quantity.
Andrej
OK, I didn't know that. Because of its 'logarithmic' performance on mine I assumed fuel gauge indicated direct from the rheostat since that's a fairly typical way they read.
 

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I've never had a car with an accurate mpg reading, they always read about 4-5 mpg better than calulating the mpg from mileage ans fuel used.

The miles to next fill up depends on how you drive. On my 1.4 the reading can go up by a 100 miles when cruising at 30-40 mph for about 20 miles. Consequently it cannot be relied upon.
 
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