Chevy Nova Forum banner

1 - 11 of 11 Posts

·
Registered
Joined
·
393 Posts
Discussion Starter #1 (Edited)
I knew the sender was wonky, got a little bent putting it in years ago so when it was full it would read well past and bounce a bit but it settle down to an accurate reading at around 3/4 of a tank. Wired in a USB charging port for my phone when I added my console and now the gauge is pegged past full. Checked the OHM resistance at tank and it is 68 which should be about right, 2/3 of a tank. I checked the resistance at the gauge and it is exactly the same. Tried grounding gauge and it doesn't go to zero so I think it is pooched, My question is when I checked the resistance at the gauge the pink wire has the 68 ohms but with the key on it also has power I would have thought the power came from the 'I" terminal to the ignition switch. Is this normal?
 

·
Registered
Joined
·
26 Posts
have you tried to unwire the usb port or go back into it to see if you moved any other wires that may affect this? my thought would be if you are reading resistance to determine fuel level I dont know that it should be powered with the key on, but you may have to double check the wiring diagram to verify that.
 

·
Registered
Joined
·
393 Posts
Discussion Starter #5
Yeah, undoing the USB doesn't change anything. What is curious, even if I unplug the fuel gauge completely it is still stuck over full, pretty sure it is pooched, must have shorted it out connecting the USB. Will do some more testing this weekend. Mostly was wondering if keyed power was normal in the sending unit wire, seemed odd to me but no one knows.
Just to confirm at this point, if gauge is over full whether connected or not, doesn't move when grounded out or anything I believe from what I have read it is done??
 

·
Moderator
Joined
·
6,502 Posts
What is curious, even if I unplug the fuel gauge completely it is still stuck over full, pretty sure it is pooched, must have shorted it out connecting the USB. Will do some more testing this weekend. Mostly was wondering if keyed power was normal in the sending unit wire, seemed odd to me but no one knows.
Just to confirm at this point, if gauge is over full whether connected or not, doesn't move when grounded out or anything I believe from what I have read it is done??
I have seen some gauges that when disconnected from power they stay at their last reading. If power gets restored and the sender value is different, then the gauge should react by changing it's reading.

I kinda doubt that wiring in a USB broke it BUT who knows sometimes.

With you having power on the sender terminal, it makes sense just like if you were to check on both sides of a dome light bulb with the doors closed. Both sides will show 12V on a meter but once the door is opened and the one side goes to ground, then only one side of the dome light bulb will show power. The other side "may" show power but it will be very, very little. This little bit of power is due to poor grounds.

Jim
 

·
Registered
Joined
·
393 Posts
Discussion Starter #8
Thanks everyone, am going to check a few things and have ordered a new gauge. I will post up when its sorted what had to be done. Just incase anyone else finds themselves in a similar predicament.
 

·
Registered
Joined
·
423 Posts
Thanks everyone, am going to check a few things and have ordered a new gauge. I will post up when its sorted what had to be done. Just incase anyone else finds themselves in a similar predicament.
Hey Numbersguy, did you get this sorted-out?
We would appreciate hearing what you found - or if still broke, we might be able to help.
 

·
Registered
Joined
·
393 Posts
Discussion Starter #10
Hey Numbersguy, did you get this sorted-out?
We would appreciate hearing what you found - or if still broke, we might be able to help.
I checked it all, had good signal from sender and everything else seemed to be in line. I replaced gauge and it works perfectly. Actually replaced the sender too with one of those tube style. I think when I was grounding the accessory plugs I had left the key on and the ground for the gauges came off and shorted my fuel gauge, trying to cut corners cost me $100. Lesson learned.
 

·
Registered
Joined
·
423 Posts
Thanks for the update. Your closure may help someone down the road.

Yeah, electricity is a nasty mistress. She does stuff under the covers you never see and makes it hard to understand her. We've ALL learned a lesson from her, I can assure you.

Glad to hear you've cleared this hurdle!
 
1 - 11 of 11 Posts
Top