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I apologize for dragging back an old thread, but I do have a related question...
I have installed one of ICM's fuel senders to report fuel levels to my MXG, but the issue I am having is with respect to calibration of the sensor.
I followed the instructions provided with the sender, and drained the fuel in the tank, taking voltage readings at 10L intervals until the tank of the car was full.
What I noticed was that I was able to get a full dataset when taking the measurements with the engine off and the electrics being powered by the battery. System voltage according to my MXG when this was going on was 12.1V.
I find however that in order to get an accurate reading, you want to perform the calibration with the engine running in order to simulate operating voltage of 14.1V through the system (this is what my system voltage is while engine is running). Problem here is that the ICM sender can't seem to see the last 20L of fuel in the tank when the engine is running. At 0L, 10L, and 20L of fuel in the tank, the sender reports the same 5.0V, which isn't ideal. When the engine is off however, the voltages at 0L, 10L and 20L are all different, contributing to a meaningful dataset.
I figured that I would just keep the dataset acquired from when the engine is off, but the issue I am finding with that is that when the dash reports that there is 0L of fuel left in the tank, my fill-up shows that there was actually at least 20L of fuel still in the tank.
The device is connected to Channel 1 on the harness that came with the MXG, if that helps.
Has anyone run across a similar issue?
And as an aside, I have found that you can get the V1 fuel sender to behave like the V2 via Race Studio 3 - it allows you to play around with the sample rate of whatever sensor you are using, depending on how it is calibrated. I have the sampling rate set at the same one as the V2 fuel sender (10MHz, if I remember correctly).
I would suggest talking to Iron Canyon. They have been helpful to other people having trouble with their units. The input voltage to the MXG doesn't affect the 5v sensor power supply, though the 12v supply to the sensors will vary.
I would suggest talking to Iron Canyon. They have been helpful to other people having trouble with their units. The input voltage to the MXG doesn't affect the 5v sensor power supply, though the 12v supply to the sensors may vary a little, but it shouldn't cause a problem this big.
Thanks for the response. Working on getting his input also. I will post what I hear back from him in case it is of any use to others in a similar position. Just thought perhaps one of our resident road racing gurus might have seen something similar in the field in the past
If they are using the 12v supply as a ratiometric, that is your problem. If it's running on the 5v, then it's not the voltage. I don't have anything from IC to know how they power it.
I think you need to modify the IC unit. There is a potentiometer inside that you can adjust. I think you have exceded the range of the setting in your IC unit. I have the instructions on how to do that if you need them
Ok, so I just got off the phone with Mark from ICM, and had a very interesting and lengthy discussion with him. He was very grateful that I reached out with my issue, as he had never seen it before, and was interested in adapting his V2 fuel sender to avoid the issue I am seeing, as there are probably others like me out there with this same issue. He also wanted me to reach back to him with results once I perform what I'm about to post.
So here goes....
As Matt Romanowski guessed, The ICM fuel sender does use system voltage as a reference, but Mark from ICM maintains that the 2 volt differential between battery voltage and system voltage when the engine is running was never enough in their testing to skew the readings as much as I am seeing them skewed to the point of seeing the same 5V output from the sender when there is 0L, 10L and 20L in the tank with engine running. The level of skew that I was seeing from my readings between engine OFF (seemed to be measuring perfectly) and engine ON (reporting 5.0V for empty, 10L and 20L remaining in tank) indicated to him that there had to be some other feedback loop in operation. In other words, something was feeding voltage into circuit while the engine was operational. There was no other way for him to explain it, as he had never seen such a skew before.
As I described to him in detail how the car was wired up, it did come to his attention thing I still had the OEM dash hooked up and operating behind my AIM MXG, and that I had simply tapped the ICM black box into the wire delivering fuel level resistance from the fuel tank level sensor/s to the dash. This was a veritable "a-ha!" moment for him, and he mentioned that the ICM fuel sender was not designed to operate with the OEM fuel gauge still connected. So while the instructions you see online for installation of this thing mention that you simply tap into the fuel sender line going to your dash for a signal, it doesn't tell you the whole story; you actually need to do more:
1) Disconnect all wiring relating to the fuel level sensors in your fuel tank that went to your dash and send the signal that signal to to the ICM black box instead.
2) Completely disconnect your Low Fuel Lamp (if applicable), as it might come on and stay on once the dash is no longer receiving fuel sender data.
3) Ensure that nothing else is tapped into the connection between the ICM black box and the senders at your fuel tank - You might need to check your service manual for a wiring diagram to ensure that nothing else is getting that same signal from the fuel level sensors in your tank. So if your ECU usually monitors fuel level for the purposes of controlling EVAP function or anything like that, you will need to lose that functionality because it has the potential to affect the accurate operation of the ICM sensor.
Mark mentioned that the alternative to #3 would be to wire the ICM black box to send its 0-5V output into your standalone ECU instead of your dash, then send the signal to the AIM dash via CANBUS.
One other thing that had Mark convinced of the need to remove the stock fuel gauge from the equation is that installing the ICM black box had the consequence of throwing off the stock fuel gauge in my car also, to the point that ever since the ICM box installed by tapping into the wiring from the tank just before it enters my stock gauge cluster, my stock fuel gauge is also indicating EMPTY when there is at least 20L of fuel left in the fuel tank. It indicates FULL accurately, but indicates EMPTY about 20-25L early...
That was about as much detail as Mark could provide into the functionality of the units, as he mentioned that he would have to inquire from the electrical engineer who designed them about other questions I had.
amso3 - If you could provide those instructions as a backup, that would be helpful. I'm not sure I will have the time to play around with the car until later this week/weekend, but the more information, the better, especially for those who may have a real need to adjust the potentiometer, as you mentioned. Obviously, if I can keep my stock fuel gauge working in my instrument cluster behind the scenes working accurately, that would be ideal, as I like to maintain as much functionality as I can on the car.
Got the ICM fuel sender working and reading more accurately now. I just had to ensure that it was not sharing the same circuit as the dash. Took care of that with a rocker switch that would allow me to revert to the stock dash if I never need to (e.g. emissions testing). Wanted to use an optocoupler for a more seamless setup, but could not find a multichannel output unit.
I've installed and calibrated the Iron Canyon fuel level sender. I've calibrated a custom sensor in gallons, but when I use the sensor in RS2Analysis it reports fuel level in liters. The value is correct, but in the wrong units. I can convert to gallons, but I'd prefer to have it report correctly.
Here is the sensor:
But Race Studio reads the data as Liters and can not be changed:
Any suggestions on how I can get the data imported with the correct units?
Very interesting. Can you please share the RS3 configuration and one of the RS2 Analysis sessions where the data is in liters so I can get them to the software writers in Italy? roger at aimsports.com
Sorry for the slow update. Roger sent me a patched version of RS2 with a drop down for units that allows me to change from l (liters) to gal (gallons). I understand that this will be included in the next RS2 release which is expected shortly.
I installed an ICM fuel sensor and loaded fuel every half gallon getting readings. It's very trick and i'm excited to use it with my MXL2.
My issue is i need to calculate some mileage with just the data i collected from my last race. Is there a way to see mileage by using the fuel level from ICM and the mileage tracked in AIM? I don't see an odometer in AIM but surely it must track distance traveled somewhere.
It could be done, but I can forsee their might be accuracy problems if you're trying to do it by the lap. How much fuel do you use? How large of a change does the ICM show? Track length?
Most times people calculate fuel burn by looking at injector flow and open time.
04-03-2017, 10:58 PM
