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Does anyone have the fuel tank resistances for the 996.2 GT3? I'm trying to set up fuel level in my car via the AiM MXS dash.
Also, does anyone have a wiring diagram for the 4-pin connector on top of the fuel pump? The big wires seem to be power and ground, and I suspect that one of the other 2 wires provides fuel level that goes to the stock dash, but not sure which one it is...
From: Durham, NC and Virginia International Raceway
It’s the violet wire. I take it at the cluster end but it’s continuous to the cluster from here.
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It’s the violet wire. I take it at the cluster end but it’s continuous to the cluster from here.
Thank you! Do you also happen to know the resistance values for the tank and/or have a fuel table for the 6.2 GT3? If I can't find a fuel table then will have to figure out which resistor wire I will need.
I don't. I just build them for each car. Do it once and it's done.
I was told that I need to find the resistance of the stock fuel tank in order to figure out what kind of resistor I need... Which resistor do you use for a 6.2 GT3 tank?
Is it linear? I was under the impression that it wasn't based on some posts in the cup car forums.
It's not linear...It's been awhile since I did the Iron Canyon gadget on my 996.2 cup but I do recall that. I just added a gallon at a time and measured the resistance after each gallon was added...did this from empty to full and it was amazingly accurate once i go it to "talk" o my AIM dash.
It's not linear...It's been awhile since I did the Iron Canyon gadget on my 996.2 cup but I do recall that. I just added a gallon at a time and measured the resistance after each gallon was added...did this from empty to full and it was amazingly accurate once i go it to "talk" o my AIM dash.
Which resistor did you buy? I don’t know the resistance range of the fuel tank…
I may have a sending unit in a box...i can probably get an ohm value at the top and bottom of the swing. I would imagine that its a linear scale?
Would you be able to tell me the resistance at max fuel capacity? If I know that value then I can buy the proper resistor and then I can do the calculation at home. Per the instructions from AiM: "...after obtaining the resistance of the fuel level at maximum capacity multiply that value by 9, and then buy the resistor closest to that value..."
I do have a voltmeter, too. Do I just tap into the the purple wire on the fuel pump harness and measure the resistance after filling the tank completely?
From: Durham, NC and Virginia International Raceway
It’s not linear, that’s why you need to measure and create a sensor curve, for each gallon. Also taking into account the fuel that can’t be picked up as the floor.
It’s not linear, that’s why you need to measure and create a sensor curve, for each gallon. Also taking into account the fuel that can’t be picked up as the floor.
I understand it isn’t linear. What I’m asking is which pull-up resistor I need to buy so that I can do the proper calculation.
Per AiM instructions via the below PDF: “To correctly dimension the pull up resistor measure the two resistor values: with the fuel tank full and
with the fuel tank empty. Multiply the highest value by 9 to obtain the pull up resistor value to be used. In case this value is not available on the market choose the first round up value.
Example: if the float indicates 126 Ohm with the fuel tank full and 25 Ohm with the fuel tank empty, take 126 Ohm, multiply it by 9 and you get 1134 Ohm. Such a pull up resistor is not available on the market so choose a 1200 Ohm 1/4W resistor (very prudential power value) with a 5% precision.”
From: Durham, NC and Virginia International Raceway
Sounds clear to me. Take the measures and do the calculation. The measures won't change (from top or bottom) but you'll get your needed information. If I had a 996 Cup, I'd do it for you, but you have one and you have the right tools.
Sounds clear to me. Take the measures and do the calculation. The measures won't change (from top or bottom) but you'll get your needed information. If I had a 996 Cup, I'd do it for you, but you have one and you have the right tools.
Happy to do this myself. Just want to make sure I’m doing it correctly.
Looking at the picture of the fuel pump harness in one of my earlier posts—is the purple wire the correct one to tap into?
I’ve also never purchased a pull-up resistor. Where is a good source to purchase them? Could you possibly share a link?
10-30-2023 | 11:51 AM
996 GT3 fuel tank resistances/wiring
