Thread: Fuel economy from 2nd hand motor

I'm no Disco expert, but generally trip computers work by basing their values by measuring injector pulse width and then using a lookup table to convert that into a consumption figure. At least the ones in other cars I know do, so i'd expect it to be off if the engine is not identical.

On my other car, every single injector comes from the factory with a measured value that then has to be input into the car computer so that it can adjust for that particular injectors characteristics.

Could be that the newer injectors have a bigger hole and provide more fuel.
Andrew

Originally Posted by shining

I have recently replaced my motor with a low km 2nd hand unit. (due to a catastrophic time belt failure). The motor is an MY2010 TDV6 with 45K kms. On the trip computer the old motor (MY07 with 215K kms) was averaging 9.4L/100km. The new one is currently at 10L/100km for the same usage profile. I purchased the vehicle at 100K kms so I don't know the early economy was. Questions Can I expect the economy to improve? Do I need to set/reset something in the carputer as I have gone from a EURO III to a EURO IV motor? (The motor replacement was NOT done by a dealer). Cheers.

Sorry to hear that mate. Have just had same thing happen to mine. Not sure if I'll be getting it fixed yet or not. Up to the bank!!

Hi Pete.
Weighing it up I had to spend the dollars. It would have cost me a lot more to get into something comparable. I don't thrash it and now I have a "new" motor.

Motor could still be a bit "tight". Some diesels start to return best fuel economy after the first 100,000 kms.

Originally Posted by shining

Can I expect the economy to improve?

I doubt it will improve much - as the run-in for your original motor may have been better. In my experience (D3 and D4 2.7), there was not much improvement after about 20,000km.

Originally Posted by shining

Do I need to set/reset something in the carputer as I have gone from a EURO III to a EURO IV motor? (The motor replacement was NOT done by a dealer).

Your tagline says you have a MY07 - in which case it was a Euro IV motor. So theoretically no change in design.

Maybe check your MAP sensor for gunk build-up. "Drive it like you stole it" - one day a month, to clear out cat converter and EGR lines. Check your air filter is clean. There's not much else to do to improve economy.

Hi shining,
I was thinking about this some more today and I just remembered there is a fundamental difference between the D3 2.7 and the D4/Territory 2.7 motors: the latter has the larger big-end bearing and crankshaft from the 3L.

I also noticed that the fuel economy of my D4 2.7 is not as good as my previous D3 2.7. I suspect the larger reciprocating weight of the crankshaft plus larger bearing increased inertia and efficiency, respectively. The positive from this is improved bottom end - so I am happy to use a little more fuel and have less risk of killing the motor.

Cheers,
Rob

Originally Posted by jonesy63

I doubt it will improve much - as the run-in for your original motor may have been better. In my experience (D3 and D4 2.7), there was not much improvement after about 20,000km.


Your tagline says you have a MY07 - in which case it was a Euro IV motor. So theoretically no change in design.

Maybe check your MAP sensor for gunk build-up. "Drive it like you stole it" - one day a month, to clear out cat converter and EGR lines. Check your air filter is clean. There's not much else to do to improve economy.

Yet to drive my D4 "like I stole it".I take on board your thoughts and now I have an excuse
12 months old now and 13000km of joy!!!!
Andrew