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Old 03-26-2013, 09:20 PM   #22 (permalink)
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I have setup my MPGuino using calculated fuel flow rate from the injector spec, and the standardish 500us delay. This seemed to give pretty sensible figures and typical averages from normal driving, followed by much improved figures after figuring out what the engine likes to do.

I've just done my first tank full and this calculated as 4% more estimated used over pump figure. After plugging in the correction, I am now getting stupid figures for flat MPG, like 60-70 along the flat.

I'm thinking the low duty cycle of travel along the flat and tick over is more sensitive to delay.

I assume the standard MPGuino software does not allow pulse counting so we can use simultaneous equations (eg long periods of tickover against full rally)

Anyway I have done the current measurement suggested at tickover and about 2500rpm and gotten delay figures of 632us and 643us.

Obviously my delay is bigger, but how accuracte is this method. Does it account for fuel momentum etc. Will 40us make much difference?

I think I'll go back to the calculated flow figure and change the delay to 645. Opinions?
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1995 Volvo 940 SE 2.3 Turbo estate (petrol) Running MPGuino from Dec 2012
Peak flat: 42mpg
Long run average: 37.4mpg (Jan 2013)
Typical average: 24mpg
UK based, gallons are imperial unless otherwise stated

Last edited by Tonys9; 03-27-2013 at 10:14 AM..
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