Thread: OBDMPG - MPG OBDII Plugin for RR 6-12-09

Re the connection issue, If I go out of the main menu and then back in it restarts the connection, so that is fine.

I reinstalled release .7 and it looks good, however I did notice the intake air temp is being reported at close to 300, and that is not right.
...Paul

The connection issue with the vehicle being turned off and not the PC is a known one, i'm working on a way to automatically reset the connection, just haven't gotten it to work yet.

I'll look over the changes in 0.8 to see whats messing up the other PID values and check with the coolant and intake air temp values.

Just looked over the code, Intake Air Temp is actually in Kelvin at the moment, hence the high numbers. I'll make sure it operates under the metric switch so it can be displayed as C or F.

EDIT:
The more I mess with the code the more I realize the additions have made it kind of clunky in certain areas. I'm going to rewrite most of the MPG stuff as functions more so than they currently are to make things more modular. It should help me track down problems easier as well. Look for a new release sometime tonight, probably in the early AM.

A plugin update is not ready yet, however the debug exe now reports data for all the RR variables. If those who are using the plugin can test to make sure the data being outputted is correct it would be greatly appreciated.

I've just begun using an ELM emulator to do some more testing before I release new builds to cut down on confusion, but I want to try and gain some outside feedback to make sure the calculations are working correctly.



Debug Link: http://www.johnmihalic.com/obdmpg/obdmpg.exe

.exe downloaded and installed, I'll run the test tomorrow and let you know what I find.
...Paul

Originally Posted by pshadwick

.exe downloaded and installed, I'll run the test tomorrow and let you know what I find.
...Paul

Thanks, my main concern is MAF values at the moment. I tweaked the original code to work well without a MAF sensor and I think the formulas for a MAF sensor need some adjustment to get realistic values.

OK here are some numbers from a short trip:

The first lot were taken travelling at a steady speed.

Car MPG reading Instant MPG from OBDMPG.exe MAF
9 790 31
18 1966 33
27 2800 13.49


The next readings were taken parked with the engine running after a short trip:

OBDMPG Digimoto
CELV blank
ECT blank
STFT1 blank 0
LTFT1 blank -5
STFT2 blank 3
LTFT2 blank -5
FP blank
MAP 34 (is this Manifold Intake Pressure?) 4.65
RPM 652 648
VSS 0 0
IAT 57.2 59
MAF 6.53 6
TP blank
FRP blank
RTP blank



Trip MPG 2143.0
Ovr MPG 2108
Miles travelled 2.10377
miles remaining 31205.0
miles traveled trip 2.10377
Gal user ovr 1.154
Gal used trip 1.05


It appears my vehicle does not return some of these PID's

There is about 60 seconds between the vales for OBDMPG.exe and my OBD software (Digimoto) as I have to shut one down to start the other.

Please let me know what other test you would like me to run.

...Paul

Thanks for the value comparisons. It looks like i've got some orders of magnitude wrong on the MAF calculations. I'll try and get that sorted out.

Am I correct in reading the data in that digimoto displayed you're fuel trims and OBDMPG did not? Thats an odd one as those PIDs are displayed pretty much directly with only the conversion factors applied.

Originally Posted by mezz64

Thanks for the value comparisons. It looks like i've got some orders of magnitude wrong on the MAF calculations. I'll try and get that sorted out.

Am I correct in reading the data in that digimoto displayed you're fuel trims and OBDMPG did not? Thats an odd one as those PIDs are displayed pretty much directly with only the conversion factors applied.

That is correct I get the fuel trims in Digimoto but no values in OBDMPG. I'm guessing that the others with no value are not supported by my vehicle.
...Paul