Hey folks.

Wondering if someone can answer this question for me.

I know most modern cars with an ECU will cut the fuel supply or at least reduce it greatly when the car is on over run but does the felicia do this?

Also if it does is it only when the engine is above a certain RPM?

Thanks

to a certain extent yes, it will only work if the throttle is completely closed, below a certain rpm (1800rpm i think?) it will reduce the fuel to a base flow, above that it will cut completely till it falls below 1800 rpm. also another function of this temporarily retarding the ignition timing too. it also depends on how much load the engine is under on the map sensor... there are deceleration maps stored in the ecu to allow for this... also there is an aceleration curve for when reapplying the throttle which temporarily enriches the fuel till the engine has picked up again (normally a few hundred revs)

Interesting stuff!

Thanks.

When you refer to the map sensor is this the 1.6 and 1.3MPi engines? As far as I am aware the 1.3 SPi doesn't have one?

Either way you have confirmed that the woman from the Energy Saving Trust was, in fact, talking rubbish by telling that it is better to decelerate in a higher gear rather than block changing down to a lower gear to get the revs up and use engine braking/over-run!

Thanks

Phil

Edited 19 August, 200916 yr by philje123

yeah but i presume if you are block changing down then you will be braking harder than you would than if you were using a high gear run down, so the net effect is the same.. every time you brake you are wasting energy that was use to accelerate the car

No I'm not... I block change down early then by the time I get to the lights etc I can just carry on in that gear. Or if the lights suddenly change then brake hard, block change down then can keep rolling ready for when they change again. All dependent, of course, on traffic conditions and if some numpty is sat behind me.

I try to DWB (Drive Without Brakes) as much as possible as this is effectively turning my expensive precious petrol into heat and rubbed off brake dust!

Phil

Phil