Help with PID 2F (Fuel)

[FoxSTI]

So far the I am getting the better results using the General purpose percentage channel as suggested by Dave F.
It does move up and down a few % but I am going to try to up the filter value to actual seconds rather then mili-seconds.

I guess you have answered my question. The dash need must use a slow stepper motor that doesn't reach much to the ODB2 signal or current value it gets (not sure how its wired).

If I can ever afford to get the Display maker I would like to make a line bar type gauge similar. There is one right now on the stock screen being used for Voltage. Maybe I can use that.

I have to say that biggest "disappointment" is that it never read 100%. It was always 96-97 and dipped to the 80's when driving. I overall I happy but I am noticing that I cannot replace my OEM cluster with this dash. which leads me to ask:

When people replace their OEM dash with one of these - specially on a car car how are they monitoring fuel? I think that adding analog gauges or any additional gauges defeats the purpose of having such a "capable" display - at least that is why I bought it.

If the fuel gauge does not work, I am going to have to relocate the dash somewhere where it does not cover my stock cluster (which defeats the purpose of having the C125 I believe).

I open to suggestions / feedback.

[David Ferguson]

Personally, I think you're being too picky. But if you want to make it read 100%+ when full (like typical dash gauges), you might consider scaling or offsetting the ODB values returned. Just play with the multiplier and offset values in the channels window you've already been looking at.

To increase the scale by 4%, you would just multiply the 3921 by 1.04, (= 4077). So put 4077 in the multiplier field and your full tank will read 100 or 101%.

Instead of scaling, you could offset the value by changing the offset to 40 (remember the value is in units of .1%). This would make a value of 0% read as 4%, so you would never see less that that. The scaling method would distribute the observed difference across the entire range.

I suspect that the OEM accuracy of the tank level sensor is probably about 5%, which would agree with what you are seeing.

BTW -- there are layouts that do offer more than one horizontal bar gauge -- so you could use one for fuel and one for voltage (or lap gain/loss!). Click the "Change.." button next to the dash picture in the Display Setup window.

[FoxSTI]

Hi Dave, yes I am being picky so an extent, also part of the learning curve. Like you mentioned earlier, I need to monitor the value sometime and compare it to my needed. My fear in all honesty if to run out of gas at the wrong time. Like I said I really don't want to have to mount the dash on the center console this just because it is covering my turn signals and fuel gauge (fuel being really important).

Here is my current setup which I am liking very much.



This is a photo I like very much of a Fiat 500 Bioposto that gave me idea to invest on the C125, but I really wonder how useful if the AIM dash on the center like that. Do you guys have any experience with it being mounted in the center like that?

https://i.ytimg.com/vi/t4gPVfiflz8/maxresdefault.jpg

[David Ferguson]

Yes, I have a few customers that mount a dash in the center console area. I have off-road trucks that mount it in front of the navigator, too.

If you really want to understand your fuel level -- you will need to do some work. I would probably do something like:

-- drain the tank (first run it close to empty, then actually pump fuel out of it, or use your fuel pump and jumper the fuel pump relay to empty the tank).
-- Observe what the ODB-II Fuel Level reading is.
-- Add fuel one to five gallons at a time, and observe what the ODB-II fuel level reports.
-- Continue until fuel tank is completely full.
-- You should end up with a table with one column showing total fuel quantity, and the other showing ODB level reporting.

Given this data, we could make a table that would take the ODB-II reading and produce a very accurate channel with either gallons of fuel, or % of fuel remaining. That you could display on your dash in the form of a bar graph.
We can also set alarms, when you are at 10% or have a 2-3 gallon reserve (somewhere around 50 miles of driving is usually good).

Based on your screen picture, I think you may be using an old version of the C125 Dash Manager; the latest is 1.81.22.0 (HEX 1.81Q). They latest software offers many layouts with more values displayed, and most of them have two bar gauges -- I think you would find that much better than the numeric value (especially if you're showing tenths of a percent!).

You can download the most recent version of C125 Dash Manager from here:

http://www.motec.com/software/latestreleases/

After installing that, you should update the firmware in your dash (Online->Update Device Firmware).

[FoxSTI]

I have the latest Dash Manager, thank you for helping me confirm. I have not upgraded firmware since I received my unit but I will run out and do it now. I think I am only showing one bar because I m not using the other for anything but I think I may use it for fuel.

I appreciate your input Dave and I don't mind going through the exercise to find out real values and build a table in dash manager. I need to get going on that because I also want a table to show boost and vac on the same readout.

When you say "jump" the fuel pump you literal mean opening the tank cover (usually under my rear seat), disconnect the fuel line to the engine and power the pump with a battery and empty the tank uh? - I love it I am up for it. I may even upgrade my fuel pump in the process.

[the_bluester]

One thing to be aware of with bar graphs is that there is not (In C127 manager anyway) an option for filtering the value as there is in numeric displays, fuel level may produce a bar graph which jumps around a fair bit depending on your sender. I would expect mine to be hopeless as the sender is quite noisy.

Is there a turn signal message in the OBD data stream? If so you could use that to generate telltales in the shift lights.

[FoxSTI]

Code: Select all

Is there a turn signal message in the OBD data stream?

I do not know. but I am willing to research how to find out. But I think the answer if no. What I may do is once I enable the I/Os I may be able to use an input to monitor the blinker status.

On a related note, is there a type of ODB2 scan tool or any tool for that matter that will allow me to send a request to the car and display what I get in return? for instance maybe I sent 012F and I see if the car sends back 412F(x). I thunk for my having something like that would be very helpful. I want to see what the car says - like the "raw" data.

One thing to be aware of with bar graphs is that there is not (In C127 manager anyway) an option for filtering the value as there is in numeric displays, fuel level may produce a bar graph which jumps around a fair bit depending on your sender.

Got it. But tables have a Hysteresis value, maybe that can help?

[the_bluester]

I have not played with the tables yet in mine, hysteresis may help though the swings in output of my sender would be greater than hysteresis would be able to cut. Can you look at the live data into your dash and see what the returned value is doing on the move?

[FoxSTI]

Guys, I am trying to set up a light from the SLM to turn on solid when GP Percent 1 < 5% and blink when GP Precent 1 <2% I will be testing these values in the near future to match the factory dummy light.

I am able to achieve the 5% light by using "User Conditions" rather than "Alarms" I am wondering if am doing this properly or if should be using "Alarms" instead?

I realize that I will probably need to generate a another channel for the 2% flashing light. Maybe use "GP 01" and Rename it to "Fuel Light 2%"

[the_bluester]

I would create them as alarms. If you create the two as user alarms you could then use them in the SLM setup. If you make the lower fuel level alarm blink red/black and put it higher in the SLM priority tree you should be able to use the one LED for it. It should be on solid under 5% and at 1% the flashing alarm will come into effect and the higher priority should make it flash the LED.