obd-2 info needed advice
 

hey guys and girls long story short im gonna be using dash command for extra gauges. my car is na.
iam getting the plx wifi and the oil pressure and oil temp sender.
i know you can have more then one screen of gauges and wanted some input from you guys.

im gonna have at least one screen for water and oil temp/pressure .
not sure how to ask this but what are other things i should have that the rx8 obd2 outputs for a na car. i figure a/f but what else should i keep my eye on.

i know i sound retarded but ive seen a list of what the rx8 obd2 port puts out and most of it dont really know what id use it for.

and advice ideas ect let me know.

You won't get the actual A/F ratio through OBD2. It will only give you Lambda. (Lambda * 14.7 for a general A/F ratio)
If you get certain parameters correct you could also extrapolate Exhaust Gas Temp through OBD2 but PLX Wifi will not pick those up.
Most useful things you can get out of the OBD2 (without additional sensors) are Lambda, Water temp and Fuel Trims.
Then there is the standard stuff.. voltage, rpm, throttle position, etc...

If I read it right with dashboard I could wright a script and it would do the math for me and I would get a rough a/f so that's good. Why would I wanna see fuel trims? I know It sounds dumb but I'm used to older efi and carbs just running standard gauges befor.

With my AP I get A/F (equivalent ratio) - is the Cobb converting the measure it gets from the OBDII?

yes the AP AFR is just an extrapolation from your wbo2/lambda.

So, as warwickben implied, you can log lambda and do the math to convert to AFR? Then maybe I should buy this at $100. Later I can add their iMFR and a sensor to add oil pressure or some other stuff. Do you know how you calclulate EGT from OBD2 data? Cool. Thanks.

Depends on what you're going to be logging with, i'm not sure PLX Wifi has a script editor of sorts to allow you to do the computations and output them in real time... but if you log lambda to a spreadsheet then yeah you could easily just multiply an entire column.

I used to use Dashcommand which had a script that calculated EGT for me in realtime. Check www.palmerperformance.com and see if they let you download it to poke around.

For what it's worth Ben, I have two PLX OLED gauges, one to a DM-100, and one to a DM-200(with ODBII)

One is used for oil temp and pressure...not off the OBDII obviously

On the other is in the OBDII and I monitor Water temp, EGT, Voltage, and a semi-quasi A/F number.

I'm useing my iPhone to run dash command till I have spare cash to buy a Mac mini for a car pc. I found a app called winebottler that will let you run pc programs on a Mac with out running dual boots ie windows and Mac osx on a Mac.

But any ways right now I'm useing my jail broken iPhone as my car pc. I jail broke it for a few reason mainly for a wifi hot spot when I install my Mac mini. But also for the video out app it will let you force what ever your screen is showing out the video out cable vs non jailbroken iPhones iPads Ipods that only a few apps will do it.
I have the video cable connected to the av switcher box then to my stock nav system.

With dash command u can get a/f a few ways. The pid SAE.lambda out puts a volt level. I think Its .6 to 1.6 . If you make a digtale read out 1= 14.7 (mite be off with number I'm half awake. Set the needle sweep rang to the low and high number for lambda numbers and just lable what ever 1 is as 14.7 and it. Will give u a idea what ur a/f is. When making gauss there a few options in dash command what pidscand cals u can use. I'm still trying to figure out which ones to use.
I'm still waiting on my plx wifi devices I'm getting the one. That I can add inputs for oil temp and pressure.

If you go to the dashxl.net. You can see the rx8 gauge setup I made.


I still not sure what gauges I should run besides water and oil temp and oil pressure and a/f. The dash board I posted I just added a bunch of other gauges just for fun.
But what other gauges should I have for a na rx8 .

I have seen 14.4, 14.5 and now 14.7. Why would i use one vs the others? I have a sCANalyzer I am trying to get working and it has a calculation if you provide the stoich number. I run non-oxy fuel.

THROTTLE POSITION Info
 

With my OBD2 connected it tells me my idle throttle position is 12% and mashed to the floor s 79% , is this normal?? Shouldn't full throttle be 100%

There are about 6 different throttle/accelerator pedal parameters reported by the ECU . Depends on which one is selected as to what numbers you see . Normal

After a 10 mile run hooked up OBD2 and my IAT Inlet Air Temp said it was 115 degrees, it was 31 outside, it slowly dropped as I drove it again but 15 miles later on highway driving it said it was 45 F. I'm getting pooe gas mileage, I've changed all the usual items and it still get 12 MPG at times, here and there 15, compression is good. Where is IAT sensor in the MAF sensor?

The MAF IAT sensor is the little brown bobble in the center of the assembly.

The actual air flow wires are up inside the 'cap'.

Probably not a good idea to mess with either.....



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Do you have the stock intake? When you're sitting still, the air is passing fairly slowly and has time to heat up. At full throttle, obviously that's not the case. Some aftermarket intakes (K&N) actually make the air hotter.

Poor fuel economy is often related to ignition problems.

Need help, I bought my car about 2 weeks ago. I have no electric speedo connection, and My Obd2 port has nothing in it. Is there something im supposed to connect and where are the part i need to connect? I mean, if anything i can just get an aftermarket but i really want to fix this if its easy. PLEASE

The OBD connectors are notoriously loose - they will pop out if pushed.

The connector is probably wired up behind the little bracket, because when it gets loose it hangs near the pedals.


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I know but the obdII sensor has nothing attached in it. is that normal?

Normal. You plug your diagnostic tool in there.