1JZ SC400: Fuel Gauge reading wrong
06-24-12, 05:17 PM
#1
1JZ Single SC400
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1JZ SC400: Fuel Gauge reading wrong
Just finished my swap, and I have noticed the fuel gauge is reading crazy. Sometimes it stays on full for awhile, then reads right after about thirty minutes of driving. Other times or most of the time it stays on full or very close to the full mark. Everything else is working like it should and it all worked correctly before the swap. I did update to the TT fuel pump before hand, but it still read 100% correct. Is anyone else ever had this problem? I am wondering if it is in the wiring part of the car somewhere. I am also using the AEM V2 standalone with patch from DM, if that matters. The only mods to the cluster is the Lextech needles, LED backlights, and the resistor R109 jumped.
I need this to be correct. I know I cant be the only one who has ever had this problem. Thanks guys!
I need this to be correct. I know I cant be the only one who has ever had this problem. Thanks guys!
06-24-12, 05:24 PM
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1JZ Single SC400
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More things that everyone might need to know. I also used a Minz fuel pressure regulator and did the 12volt mod for the seperate relay for the TT fuel pump. I really dont think that matters, but I wanted to eliminate all the possibilities.
06-24-12, 06:48 PM
#5
for me the easiest , since you have another SC400.. take out the other sending unit hat and interchange the two for diagnostics purposes. If your gauge is more accurate then you know the former sending unit is bad. If you observe the dial on the sending unit (within a white rectangular box) .. that part can wear out since it scratches over it while that lever goes up and down depending on the level of fuel. That is actually a potentiometer.. resistance changes depending on the position of the float . If you can get an ohmeter , connect it to the terminals of that potentiometer and move the float... there should be a steady rising up and falling of resistance values depending on movement of float.
Last edited by gerrb; 06-24-12 at 06:57 PM.
06-24-12, 07:08 PM
#7
hey we all learn along the process , that is the beauty of these forums , so don't be hard on yourself 
.. we are all stupid and idiots at times ..especially me 
remove the trunk cover to expose the tank .. the hat that you see right at the center of the tank when you remove that cover is the sending unit.. can take it out by unbolting I believe 8 or 6 small bolts and removing the wires on top of it for easy access ..
that hat on the left of the picture ..where my three -6an TT pump output are .. that is where the fuel sending unit is ... The center gray connector is for the fuel sender connection to the gauge .
.. we are all stupid and idiots at times ..especially me remove the trunk cover to expose the tank .. the hat that you see right at the center of the tank when you remove that cover is the sending unit.. can take it out by unbolting I believe 8 or 6 small bolts and removing the wires on top of it for easy access ..
that hat on the left of the picture ..where my three -6an TT pump output are .. that is where the fuel sending unit is ... The center gray connector is for the fuel sender connection to the gauge .
Last edited by gerrb; 06-24-12 at 07:22 PM.
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06-25-12, 11:48 AM
#12
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Your patch harness and ECU have nothing to do with the fuel gauge. Your fuel gauge does not get a signal from the ECU. I would check your sending unit in the tank, and if those check out, I would check the connections on the back of your cluster (since it's been out)
11-26-12, 04:43 PM
#14
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