What A Difference A Service Makes!

[Dacre]

I had my 2010 T4 serviced two weeks ago (by B & M in Amersham - very good service) as I had clocked up 20,000 miles. This was my first service as I bought it with 13,800 on the clock.

Prior to the service average MPG was around 54.5mpg - the last two tankfuls have seen 62mpg!

Both tankfuls have been mainly motorway miles and long distances so very few cold starts - which I find knocks the mpg down considerably - but nothing too different from my normal driving style

I check my tyre pressures weekly so I don't think that is a consideration, so I can only assume that the previous service (when car was run by Toyota Management) had used the wrong oil.

Does anyone else have any opinions as to why there would be this large decrease in the consumption apart from the oil?

Tim

[ian rooke]

Hi the last week has been unseasonably warm my fuel consumption has improved by 5mph over the last week.

[Grumpy Cabbie]

It sounds like a classic case of 5w30 having PREVIOUSLY been used. I had found it almost impossible to get a journey average over 60 mpg in any weather when mine had been filled with 5w30.

With the more expensive but correct 0w20 oil (remember this is a gen3 we're refering to) the engine will run more freely and you will easily get over the 60 mpg mark in winter and in the high 60's to low 70's in summer.

I bet you can now see what all the fuss is about regarding this wrong oil malarkey. With the correct oil the gen3 is amazingly economical but with the 5w30 it's no better than a diesel Avensis. I wonder how many owners have been disappointed with their gen3 Prius/Auris hsd fuel economy without realising a dealer had scrimpted £30 by using the wrong oil.

At least you've got it sorted now and come the warmer spring/summer weather (where heating isn't required) you'll notice a significant increase in mpg's.

[noisyhen]

Checked with local dealer before my first service that they do use 0w20 oil.

Out in car for first time today since service yesterday and noticed engine seemed to be racing quiet a bit, went down a flat road from standstill and without my foot on the accelerator, speed increased to 4 mph then to 5!

Car is back into dealer next week for them to deal with rattle problem and would like to know if anyone else has suffered anything similar?

[Grumpy Cabbie]

Did they put a new air filter in? I also recon they must have disconnected the 12v or reset the management system and it is now relearning the engine parameters etc. Perhaps they did a software upgrade too?

The racing could be the engine charging the HV Battery, cold start and its warming the engine and cat up, warming the heater for the cabin (do you keep it over 20c?) or even you've just decended a steep hill. If you're in 'normal' mode the car runs the engine more continuously in the warm up stage until it is happy. With 'eco' mode the engine will switch on and off more in the early stages to save fuel.

The Prius is happy to throw warnings if there is a problem and I think they work in three stages. I once had a hybrid system error warning message flag up (in writing on the screen), the car didn't start but did on the 3rd attempt. This was sorted by the dealer under warranty and was a failed HV Battery ecu. The car was still drivable and wasnt in snail/get you home mode. The dealers said the next warning if things were more serious would be a yellow exclamation mark which is a get home and call dealers warning and a red one would show if the car was completely kna*kered and you should pull over asap.

As you have non of these I wouldn't be too worried. I'm pretty sure it was reving because it was cold or the heater was warming up, or for the reasons given earlier.

Hope this helps.

[johalareewi]

noticed engine seemed to be racing quiet a bit

That isn't unusual. You will get used to the lack of a direct link between engine revs, pedal position and speed. The ICE (petrol engine) does its own thing from time to time.

[noisyhen]

noticed engine seemed to be racing quiet a bit

That isn't unusual. You will get used to the lack of a direct link between engine revs, pedal position and speed. The ICE (petrol engine) does its own thing from time to time.

I've never noticed this occurring like this until after the service.

[noisyhen]

Did they put a new air filter in? I also recon they must have disconnected the 12v or reset the management system and it is now relearning the engine parameters etc. Perhaps they did a software upgrade too?

The racing could be the engine charging the HV battery, cold start and its warming the engine and cat up, warming the heater for the cabin (do you keep it over 20c?) or even you've just decended a steep hill. If you're in 'normal' mode the car runs the engine more continuously in the warm up stage until it is happy. With 'eco' mode the engine will switch on and off more in the early stages to save fuel.

The Prius is happy to throw warnings if there is a problem and I think they work in three stages. I once had a hybrid system error warning message flag up (in writing on the screen), the car didn't start but did on the 3rd attempt. This was sorted by the dealer under warranty and was a failed HV battery ecu. The car was still drivable and wasnt in snail/get you home mode. The dealers said the next warning if things were more serious would be a yellow exclamation mark which is a get home and call dealers warning and a red one would show if the car was completely kna*kered and you should pull over asap.

As you have non of these I wouldn't be too worried. I'm pretty sure it was reving because it was cold or the heater was warming up, or for the reasons given earlier.

Hope this helps.

Thanks for the info, I'll check it out with the dealer to see what they say.