trip computer?

[finallyrangie]

Hello people,

Does anyone know how the computer calculates fuel consumption, I have just fitted a diesel engine into my P38 and the computer assures me I am using 35-40 litres per 100:eek:, I am pleased to report that at the pump its about 11 on a usual week to work:), shopping and the like.

When I got the car it had been sitting for 5 months and said 90 litres per 100 but I thought at the time it was because it had been running without moving for months.

Thanks for any suggestions

[mtb_gary]

I take it you have reset the calculator?

Gary

[finallyrangie]

I think so, I have reset trip 2 and it comes up with calculating range etc, it does change in traffic or on the motorway, it's just way out.

[PeterAllen]

Reset it and start again. Sounds like it is just averaging down from the 90 litre reading you had when you got it. Previous owner must of had it running in the shed for a while to get such a high previous reading.

[PeterAllen]

On mine its trip 1 that it measures range and fuel usage. Trip 2 on mine is just for distance. If yours is the same reset trip 1.

[Keithy P38]

Out of curiosity, what engine did you fit up?

[finallyrangie]

Out of curiosity, what engine did you fit up?


I put the 2.8 tgv engine in, a red P plater was kind enough to make the engine in my old disco available when he jumped a traffic light. Good old fashioned mechanical diesel with plenty of low down torque, seems to move the old bus along quite nicely.

[benji]

The fuel consumption is calculated from the injector opening times over distance.

I know the 2.8 bitsamisn punts along a delica fairly well; sounds great.

[Hoges]

check out principle behind trip computer economy (http://www.rangerovers.net/forum/7-range-rover-mark-ii-p38/24854-principle-behind-trip-computer-economy.html)

Apart from the info here which points to the Bosch/GEMS ECU my experience with a gunky fuel sender, which only showed 50% full on a full-to-the-brim tank indicates that the fuel sender level also provides data for the calculation. In the case of the 50% full reading, the average fuel consumption was showing 28L/100km and the distance to empty 350km after resetting the trip meter...

While all of the sensors/ECUs mentioned in the rangerovers.net posts appear to be implicated somehow...I'm uncertain as to which does what....:confused:

Given that the TGV engine presumably runs an independent ECM (or not) then without it being somehow integrated as per the Bosch/GEMS arrangement (or the 2.5 diesel option), it's unlikely you'll get a meaningful result from the new setup...

cheers

[finallyrangie]

Thanks Hoges

The fuel sender works perfectly, full is full as you would expect. The tgv engine is a modified version of the 300 tdi and so has no computer at all, the readings do change depending on how I have been using the car so I am hoping I can figure it out.