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Diesel Engines A forum dedicated to diesel engines fitted to Volvo cars. See the first post in this forum for a list of the diesel engines. |
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Wildly inaccurate MPGViews : 1782 Replies : 17Users Viewing This Thread : |
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Sep 8th, 2017, 07:23 | #1 |
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Wildly inaccurate MPG
Hi all, my first post so apologies if it's in the wrong section!
I've been surprised at the rate my 03 V70 D5 AWD geartronic has been using fuel. I measured economy between the last 3 fill ups (reset trip and mpg) and found that the trip computer was telling me 46.5mpg but the calculated economy from the pumps and odometer was just 37! This was consistent between fill ups. Does anyone have any suggestions what might cause the indicated mpg to be 25% higher than actual? There's no sign of Diesel on the driveway so I presume it's all making its way into the engine somehow. I'm thinking that the indicated figure should be achievable with the roads I drive and my driving style. I do my "spirited" driving in my other car (a highly tuned N/A mx5) so driving this one is all about fuel economy. My last practical car (02 Toyota Avensis 2.0D) managed around 63mpg actual measured economy so I'm pretty shocked how thirsty this one is! Has anyone else experienced similar? |
Sep 8th, 2017, 14:57 | #2 |
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Pretty normal fuel consumption for an auto d5 of that era in my experience. The dim display is never that accurate.
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Previous -03 S40, 04 V70 D5, 04 V70 D5 Sport, 05 V50, 07 S60 D5, 09 V70 D5 R design, 12 XC60 DrivE, 15 V60 D3 Current- 05 XC90 D5 Exec, 12 XC70 D4 AWD Se Lux, 14 S80 D3 Se Lux |
Sep 8th, 2017, 22:07 | #3 |
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Yeah, it's not too horrendous but it's 40-60mph cruising almost the whole way from home to work so I was hoping for a little better... My last car managed 15mpg higher than quoted on the same route which would put the trip computer mpg about right.
10% out I could deal with bit 25% out makes me feel like something isn't right... |
Sep 9th, 2017, 08:22 | #4 |
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I think a lot of the internet hype about the astonishing frugality of the Euro 3 D5 engine comes from the utter lies the trip computer tells. On my 2004 V70 T5 it always over reported by 20% or more too.
Sensibly, a 1700KG car with an automatic gearbox and AWD system with what is not exactly a state of the art diesel engine cannot be expected to do much better than 38mpg. For comparison, my C70 is about the same weight, has a newer revision of the engine, and is FWD and a manual and that averages 43mpg if I'm gentle. Lots of motorway driving. I'd expect to do no better than you in our brand new manual XC60 D5.
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Sep 9th, 2017, 08:41 | #5 |
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Good to know I'm not the only one who's noticed this! Sounds like perhaps this is normal behavior for these cars.
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Sep 9th, 2017, 13:25 | #6 |
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55-60 mpg measured at the pump after a motorway cruise euro 3 d5 manual.
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Sep 9th, 2017, 15:54 | #7 |
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What fuel are you using?
I have a Euro IV 185BHP D5 auto and whilst mines not that badly out, it seems to be closer with Shell/V-Power then when I used Tesco Diesel for a bit. |
Sep 9th, 2017, 18:29 | #8 | |
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Quote:
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Sep 9th, 2017, 20:18 | #9 | ||
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It's funny that it would make a difference since the ECU will be doing its mpg calculations based on how long the injectors are open for rather than any sort of power measurement. The only way I can see the fuel brand making a difference to the accuracy is if the shell fuel was more viscous so less flow for the same injector time. Quote:
Yes, I have been zeroing the average speed, mpg, fuel consumption and trip when doing the calculations so it should be a fair comparison. Tyre size is standard and I'd expect that to affect the odometer and mpg numbers equally. Last edited by LoudPedal; Sep 9th, 2017 at 20:24. |
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Sep 9th, 2017, 20:59 | #10 | |
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Quote:
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