[pahwa]

A dumb question here - Did you change the tyres? I did an upsize by 1" and resulted into 30% skewed odo and speedo on my Maruti Zen.

[mayankk]

Performing CPR here.

My dad uses a Dzire VXI(new one).

Now, we fired a driver 3 months back, because he was caught with 3 2 litre bottles in his bag, and the average of the car had dropped to about 10-11 kmpl. The MID constanly showed 16kmpl, but this was hardly close.

Now, with a new driver, who has been told in no uncertain terms any theft will result in immediate termination with no scope for working in the society ever again, teh MID still shows 16KMPL, but the car is not giving more than 12-13 kmpl(Vindication here. Theft WAS happening).

Can other Dzire/Maruti owners comment here?

Dad is adamant that get it checked, else I will sell it off, and get a new car (He's a petrol head's father. I suspect he may just WANT to get a new car).

But I dont want to get rid a car thats just under 3 years old, still in warranty, and running good without any other issue.

[Rohitj92]

Originally Posted by mayankk

Performing CPR here.

My dad uses a Dzire VXI(new one).

Now, we fired a driver 3 months back, because he was caught with 3 2 litre bottles in his bag, and the average of the car had dropped to about 10-11 kmpl. The MID constanly showed 16kmpl, but this was hardly close.

Now, with a new driver, who has been told in no uncertain terms any theft will result in immediate termination with no scope for working in the society ever again, teh MID still shows 16KMPL, but the car is not giving more than 12-13 kmpl(Vindication here. Theft WAS happening).

Can other Dzire/Maruti owners comment here?

Dad is adamant that get it checked, else I will sell it off, and get a new car (He's a petrol head's father. I suspect he may just WANT to get a new car).

But I dont want to get rid a car thats just under 3 years old, still in warranty, and running good without any other issue.

My 2013 Dzire vxi gives a mileage of 12-13 in 100% Mumbai traffic conditions. Although, the MID shows mileage of 14.7-15. The car has just covered 6000kms.

[a4anurag]

Originally Posted by Rohitj92

My 2013 Dzire vxi gives a mileage of 12-13 in 100% Mumbai traffic conditions. Although, the MID shows mileage of 14.7-15. The car has just covered 6000kms.

I guess you follow the full tank method for FE calculation so the next time you do a full tank, please RESET the average FE in the MID and then check for the readings obtained by the end of the tank.

I reset the MID (Avg FE) every full tank to get the reading pertaining to that full tank filled.

Anurag.

[mayankk]

Originally Posted by a4anurag

I guess you follow the full tank method for FE calculation so the next time you do a full tank, please RESET the average FE in the MID and then check for the readings obtained by the end of the tank.

I reset the MID (Avg FE) every full tank to get the reading pertaining to that full tank filled.

Anurag.

How do you reset the MID FE display?
May sound noob, but Ive hardly driven the car.
I didnt know it was possible to reset the average reading!!

[a4anurag]

Originally Posted by mayankk

How do you reset the MID FE display?

I didnt know it was possible to reset the average reading!!

It is simple:

1) In the MID bring up the Average FE on display by pressing the illumination control stalk (found in the speedometer ring);

2) Long press the same stalk now till the MID displays "--.-km/L"

Voila!

Anurag.

[KarthikK]

Originally Posted by itsprak

Not just the MID, even the speedometer / odometer readings are not always accurate.
...
I have observed that speed indicated in the speedometer is always more than what is indicated in the GPS and also the difference between the two increases with speed. The difference is almost around 5 KMPH to 10 KMPH when driving at more than 100-110 KMPH. I have also observed that the distance traveled indicated in the odometer differs quite a bit from what is indicated in the GPS.

The speedometer is always calibrated to read a little more than the actual true speed. I had read some article once that said this is done deliberately by the manufacturers so that the driver gets a feeling of being quicker (than he actually is) and is likely to get freaked out by the false higher number earlier. Human psychology

Originally Posted by Trust_In_Thrust

I have seen the MID on fiats to be very accurate while that on the city was vague and nowhere close to real figures.
MID will be more close to real figures when the instrumentation and processing information calculated from various methods like the injection cycles etc is done using more sophisticated hardware (read more expensive) .

I have found both my Fiats (Punto multijet / Linea T-Jet) to report almost 0.1-0.2 kmpl higher fuel efficiency than the actual number measured through the tankful-to-tankful method. Always! Since that variation is very small, it can be considered negligible enough say the MID is fairly accurate most of the times.

I also use a 2010 version City AT for urban commuting and find that this car also reports a 0.1-0.2 kmpl variation with actual values. Didn't really find that way off the mark compared to the Fiats in my case. I haven't measured too many times though, so I can't call my test conclusive either.

[a4anurag]

Originally Posted by KarthikK

The speedometer is always calibrated to read a little more than the actual true speed. I had read some article once that said this is done deliberately by the manufacturers so that the driver gets a feeling of being quicker.

+1, that is done wantedly by manufacturers.

Car: Swift ZDi (All stock)

Speedo Display: 80 kmph
GPS Speed: 77.4 kmph
ECU (Recorded) Speed: 77 kmph

Data collected using ELM 327 OBD 2 reader.

Originally Posted by KarthikK

I have found both my Fiats (Punto multijet / Linea T-Jet) to report almost 0.1-0.2 kmpl. I haven't measured too many times though, so I can't call my test conclusive either.

Good to see a negligible difference between the MID Data and full tank readings. In my Swift, I am experiencing a difference of 0.6-0.8 kmpl where the MID gives higher figures as compared to actual full tank data.

Anurag.

[SydNaz]

I guess the average fuel consumption reading of the MID is fairly accurate as the information is obtained and processed from the ECU. But one must be careful in using it correctly. It is prudent to reset the avg. fuel consumption reading every time you use the car, because i feel how the avg fuel consumption is calculated is total distance traveled divided by total fuel consumed over the course of the trip. but if we don't reset the avg. fuel consumption reading overtime, then the readings would most certainly be wrong. Hence for accurate readings the avg fuel consumption of the MID would probably need to be reset for every trip.

[Jeroen]

Originally Posted by SydNaz

I guess the average fuel consumption reading of the MID is fairly accurate as the information is obtained and processed from the ECU. But one must be careful in using it correctly. It is prudent to reset the avg. fuel consumption reading every time you use the car, because i feel how the avg fuel consumption is calculated is total distance traveled divided by total fuel consumed over the course of the trip. but if we don't reset the avg. fuel consumption reading overtime, then the readings would most certainly be wrong. Hence for accurate readings the avg fuel consumption of the MID would probably need to be reset for every trip.

No, both readings would be correct, but represent something different. The principle remains the same. If you don't reset its the actual cumulative average for whatever period/mileage you did not reset. So if you never reset from the time you bought the car new it will show you the average fuel for the total time/mileage of the car. If you reset it weekly it will show you the average for that particular week. If you reset it every 1000km it will show you the average for that 1000km.

The accuracy is not really affected by how long or short your measurement period is. Both the liter used and the mileage are cumulative measurement and their accuracy is a percentage of the reading. But as both are cumulative, the accuracy of the reading remains the same.

My Jaguar can display two averages with individual resets. One I have kept without a reset since the day I bought it. So its shows me the total average fuel consumption for this car. The second counter I reset every time when I fill up and I check the liters of fuel I put in with the numbers on my display. It gives me an idea on short term fuel usage and accuracies of the measurement. Also, i do this because Im a bit nerdy and anal about this stuff and I enjoy fiddling with it.

Jeroen

[puneeth2]

I own a Hyundai Grand i10 which does not show Fuel Efficiency on MID. I have seen a few cars displaying instantaneous fuel efficiency on MID. I was wondering if there is an way to tweak the software to get MID to display fuel efficiency? As I have understood, ECU would have all the necessary data to calculate this. Is there any way to use that data to show fuel efficiency on MID?

[Jaggu]

I am not sure about MID displaying the same, but if you get a OBD reader and hook it up with a smart phone, you should get information on what are the parameters that can be accessed. Based on this if one can really hack the system, maybe it is possible to display it over MID.

Let us wait for electronics guys to come in

[aswin ajith]

I have the Type 1 Ritz from 2009 which doesn't not have an MID. Just the usual odo trip and time. But the new updated Ritz(2012) displays all the info like instantaneous average FE and DTE if I remember right. Is there a way to get the old ones to display these info. Just to clarify both clusters are absolutely same. Not one difference.

[joybhowmik]

I am not sure if this is the right thread to post my question - and request Mods to move it to the right place if not.

Problem: Recently there has been a big drop in reported Distance to Empty in MID ~ 126 km!
Earlier the reported DTE used to be 484 km on a full tank. Recently the reading is 368 km.
Trying to understand what could be wrong here.


I have a scheduled appointment at the dealers workshop tomorrow - and plan to ask one of the senior technicians to lead investigations.

Any helpful pointers from the community will be much appreciated - as that will help in the diagnostic process.


Context
1) Car: "Milemuncher" Innova (Innova VX 2009). Purchased new in Nov 2009
2) Total KMs driven to date: 65k
3) Service History: On time service every time. Sometimes before the required "miles" are up
4) Driving style and Usage: Driven gently. Usually engine RPM meter is in the 1k to 2k band, very occasionally going to 2k to 3k range.
5) Any accidents? - NO.
6) Any smell of fuel? - NO. Visual inspection of fuel tank done - no dents anywhere.
7) Any major mechanical/electrical issue (including error lights on dashboard) ever reported on the car? NO.
8) FE is just above 10kmpl in city with AC on- measured from MID. I do switch the engine off when forced to wait long at traffic-lights. Better FE on highways.
9) Tyres: Standard Bridgestone H/T B390. Inflated to right pressure at all times (35 psi).
10) Any fitments e.g. luggage carrier /lights on top etc that can significantly change drag characteristics? NO. Nothing is fitted outside.

[arun francis]

Hi, My name is Arun and I am driving a 2010 corolla.
Nowadays all cars are having fuel efficiency indicators, ie they show average fuel consumption, instantaneous fuel consumption, distance to empty etc.
But I wonder whether we can really rely on it.
In order to show the correct fuel consumption the ecu or on board computer has to monitor the actual fuel consumption by the engine, this can be done by fixing flowmetres in fuel lines.
But I feel that most manufacturers are putting a software/algorithm in the ecu, so that the fuel consumption is calculated by taking into account engine speed and vehicle speed.
I invite other BHPians to share their knowledge in this regard.