A few questions

[tdi90]

Running torque on my phone and have a few questions regarding some of the readings I'm getting;

1) what should a derv normal running temp be when fully warmed up? My display showed a max of 86 C today in traffic. running around it was at 84 C.

2) What should the MAF sensor readings be? at idle mines at between 12.5 and 13 g/s (what ever the hell that means )

3) The MPG display was scaring the hell outta me! lowest was 7mpg the highest was 23mpg even after engine fully warmed up. I dont have the multi function dash so aint got nowt to compare it to so hoping the torque app is wayyyyy out!

[rover54]

Originally Posted by tdi90

Running torque on my phone and have a few questions regarding some of the readings I'm getting;

1) what should a derv normal running temp be when fully warmed up? My display showed a max of 86 C today in traffic. running around it was at 84 C.

2) What should the MAF sensor readings be? at idle mines at between 12.5 and 13 g/s (what ever the hell that means )

3) The MPG display was scaring the hell outta me! lowest was 7mpg the highest was 23mpg even after engine fully warmed up. I dont have the multi function dash so aint got nowt to compare it to so hoping the torque app is wayyyyy out!

The only way when measuring MPG is to do a brim to brim reading. i.e record the mileage when the tank is full and then again when you refill, then you can work out an accurate MPG.

I know diesel get very hot and the fuel load in the tank is insufficient to cool it, hence the diesel cooler at the rear of the car. On that basis the temperatures you are reading are more than likely typical.

What concerns me about these apps is that they can develop a sense of paranoia with all the figures they can produce when gut instinct by the sound of how an engine is running now takes a back seat.

[Trophy Blue Tourer]

Edd! I think the O/P means the running temp of the engine cooling system rather than the fuel temp which isn't (as far as I know) shown on the OBD!! as in "a Derv" meaning "a Diesel" car!!

So his running temps are about right!! (if not slightly under what would be optimum) given that his fan will probably be on for the air con given the current air tempratures and blowing round the engine bay !! just goes to show how difficult it can be to get the M47r engine to overheat!!

O/P !! cant help with the MAF readings!! - somebody who can will probably be along shortly!!

On the third point the fuel consumption readings you get on the OBD are the instant ones only so for around town low gear and accelerating up thorough the box they probably arnt far out!! - As Edd said the only accurate way to check MPG is a "brim to brim" check - he's also right about the "apps" being liable to induce paranoia if you watch them all the time! !! I use them to help check systems once a month or so or help diagose if I have a particular problem!!

HTH??

Andy

[T-Cut]

Originally Posted by Trophy Blue Tourer

On the third point the fuel consumption readings you get on the OBD are the instant ones - - -

This is true if the computer was reset seconds before the reading is made. In my experience, the mpg figure is the aggregate of data created since the last reset. This means you can get almost any figure you wish by resetting the computer, and drive accordingly whilst taking the data from the display. For example, a reset followed by brisk acceleration will display something like this.



So, the OBD display should never be reset if you want to display anything approaching the true mpg figure. After allowing a few thousand miles of uninterrupted data to accumulate, use the brim to brim calculation to trim the OBD factor to display the accurate mpg. This display will reflect your brim to brim calculation as long as to stick to the same driving regime as used in the brim to brim calculations. How to do the factor adjustment is given in the latest edition of my Trip Screen Diagnostic Mode write up.

TC

[Trophy Blue Tourer]

Originally Posted by T-Cut

This is true if the computer was reset seconds before the reading is made. In my experience, the mpg figure is the aggregate of data created since the last reset. This means you can get almost any figure you wish by resetting the computer, and drive accordingly whilst taking the data from the display. For example, a reset followed by brisk acceleration will display something like this.



So, the OBD display should never be reset if you want to display anything approaching the true mpg figure. After allowing a few thousand miles of uninterrupted data to accumulate, use the brim to brim calculation to trim the OBD factor to display the accurate mpg. This display will reflect your brim to brim calculation as long as to stick to the same driving regime as used in the brim to brim calculations. How to do the factor adjustment is given in the latest edition of my Trip Screen Diagnostic Mode write up.

TC

Sorry mate !! thats a pic of the trip computer that you have posted!! - NOT the OBD!! - if you read the O/P he states he doesn't have one plus he is getting his figures from the app on his phone which will be conected to the diagostic port so recives the same data stream that the OBD uses (the system you access in the trip/total milage screen) which is and only the instant moment to moment figures!

So !! And i'll say it again the figures are probably not that far out!

Andy

Edit - Umm arn't the OBD fuel consumption figures in "metric" anyway as in kilometers per liter or am I just imagining that bit?

[alan richard]

The Torque app. can't read MPG figures from the R75. It has it's own methods of calculating it, and I've never found it to be very accurate, myself.

Brimming the tank is of course the only reliable method.

MAF g/s is grams per second of air entering the engine, which naturally increases with engine revs. I'll go have a look at mine, but don't imagine it's a figure you need to worry too much about.

-a

[T-Cut]

Originally Posted by Trophy Blue Tourer

Sorry mate !! thats a pic of the trip computer that you have posted!! - NOT the OBD!! - if you read the O/P he states he doesn't have one plus he is getting his figures from the app on his phone which will be connected to the diagnostic port so receives the same data stream that the OBD uses (the system you access in the trip/total mileage screen) which is and only the instant moment to moment figures!

Yea, I realised that after posting it, but the trip computer is using the same data as the OBD stream especially after a point of reset. I used that to show how the fuel consumption can be virtually anything you want if the data is taken at the appropriate instant.

TC

[tdi90]

Sorry, I ment engine temp

RE the MAF readings, pretty sure my BOSCH one is almost knackered as the car surges at around 2100 rpm. I have a cheapy ebay one as a spare but thats just plane pants lol.

Upgraded to the full version of torque and for £2.95 it was a bargin!