OBD2 scantools and engines

[JanK]

Hi,

I am new to this forum, so I am sorry if this is offtopic or was already discussed. Anyway, search did not find anything useful, so I am posting this question.

I own a diesel car (as very common in Europe where I live) and I would like to know more about OBD2 diagnostics related to petrol (ehm, diesel) saving.

I have recently bought http://www.obdtester.com/elm-usb cable for use with free (and open source) pyOBD: http://www.cs.unm.edu/~donour/cars/pyobd/ . It works quite OK, but I do not know what should I watch in the application. I have no fault codes stored in my car (so it should be OK), but I would like to know what should measured values (live data) display, what range should it be, how should it change when I push pedal, etc. I understood that fault code is present when something is really really wrong, but this is not my case - I just want to know that everything is 100% condition and my car is not consuming more than necessary. Any help?

Thanks,

Jan

[GasSavers_BEEF]

one of the biggest things you can use this for is to modify you driving style. most people don't realize that you can increase your efficiency by about 30% just by modifying the way you drive the car.

I personally have a scangauge II (www.scangauge.com) it will show you in real time your MPG along with trip MPG and other things. I use mine for IAT intake air temperature as I have a warm air intake on my car and run 150 degree intake temps (that is in degrees F not degrees C).

I would have recomended the scangauge first because it is a small display and you don't have to lug around the laptop with you. you do have the option of data logging which the scangauge does not have.

[JanK]

Originally Posted by BEEF

one of the biggest things you can use this for is to modify you driving style. most people don't realize that you can increase your efficiency by about 30% just by modifying the way you drive the car.

I personally have a scangauge II (www.scangauge.com) it will show you in real time your MPG along with trip MPG and other things. I use mine for IAT intake air temperature as I have a warm air intake on my car and run 150 degree intake temps (that is in degrees F not degrees C).

I would have recomended the scangauge first because it is a small display and you don't have to lug around the laptop with you. you do have the option of data logging which the scangauge does not have.

I did not mean to watch anything while normally driving. That's dangerous and I have built-in trip computer for this purpose.

What I meant is to understand "measured values", i.e. what should I watch to see if anything is getting wrong with the engine and should be replaced to keep petrol consumption low. With measured values I mean this function:



also single-measurement function might be of use. more images of functions or here.

By the way, my diesel car says "Not intended to meet any OBD-2 requirements" ;-).

[GasSavers_BEEF]

I think OBDII is a united states thing (or maybe EPA which is also US).

many times, the particular readings are just the values at a given time. the 23 degrees C is probably normal for the time of year. it is about 65ish degrees F and would probably be much lower in the winter.

I would say that depending on how new it is, you probably won't see anything out of the ordinary unless it is throwing a code or something. I will admit that I am not an expert but just as an example a while back, my car lost about 2-3 mpg and I couldn't figure out why. I chocked it up to a funny fill on the tank (that does happen sometimes) and during the next tank, my check engine light came on stating that my EGR valve was faulty. I cleaned it and my mileage came back.

my car is 13 years old and has 192,000 miles (~308,000 kilometers) so things come up on it from time to time.

I will also say that diesels are different creatures too. I have never owned a diesel and the diesels we have around here are monsters (mostly in 3/4 ton trucks) my brother-in-law has one but there again it is a 7.3 liter and will haul a house (maybe slight exaggeration there)