Fuel Sender ground
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Thanks. Fuel gauge reading full all the time. I've had the unit out before and even tried cleaning the contacts but it still reads full all the time. I was told recently that a problem could arise at the C8 connector on the display connector but I thought the more common issue was at the tank end. But the three wires running into there are faded and I'm not sure what color they are - pink, green (?), brown w/stripe (?).
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It does indeed read full disconnected. My understanding was that the default display without a fuel sender installed is to show completely full. Not to be too dense but is that consistent with what your saying? Assuming the green wire is the ground, is there any location or locations to look at first? In other words, what now?
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OK. I pulled the unit out and did the ohms test. Got a high reading of 96 and at the other end it didn't get below 12 or so. Are these readings acceptable?
Also, the two ground wires meet at what looks like a spade connector on top of the housing. It is VERY rusty and immovable. Should I try to force it off (or replace) and clean that area? Thank you all for the input.
Also, the two ground wires meet at what looks like a spade connector on top of the housing. It is VERY rusty and immovable. Should I try to force it off (or replace) and clean that area? Thank you all for the input.
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GM gauge senders are typically 0 - 90 ohms
What is the resistance on the ground side of the gauge?
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The cluster sends 5 volts to the sender element, so there should be 5 volts on one of the connector pins (ignition on, of course).
The sender element is basically just a potentiometer. The wiper voltage should vary from zero to 5 volts as the float is moved up and down.
There is a very long "damping" time on the fuel level gauge, so it takes a while for the gauge to reflect a change in the float level (keeps the gauge from jumping up and down when the fuel sloshes around in the tank). This got me when I took my sender out of the tank. I was moving the float but the fuel gauge didn't seem to be changing. I wasn't waiting long enough.
The sender element is basically just a potentiometer. The wiper voltage should vary from zero to 5 volts as the float is moved up and down.
There is a very long "damping" time on the fuel level gauge, so it takes a while for the gauge to reflect a change in the float level (keeps the gauge from jumping up and down when the fuel sloshes around in the tank). This got me when I took my sender out of the tank. I was moving the float but the fuel gauge didn't seem to be changing. I wasn't waiting long enough.
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I measured resistance from the ground wire on the orange connector to what I referred to as the "spade connector" on the top of the housing and it reads open. Infinity. That shouldn't be, right?
Please bear with me on this. I'm getting better and more comfortable about electricity and measurements but still lack some confidence in what I'm doing. So... what I did - is that what you were asking?
What about the ground wire that goes from the "spade connector" to the white plastic thing (don't even know what it's called) into which the power wires run. Should that/can that be tested?
Thanks.
Please bear with me on this. I'm getting better and more comfortable about electricity and measurements but still lack some confidence in what I'm doing. So... what I did - is that what you were asking?
What about the ground wire that goes from the "spade connector" to the white plastic thing (don't even know what it's called) into which the power wires run. Should that/can that be tested?
Thanks.
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"The cluster sends 5 volts to the sender element, so there should be 5 volts on one of the connector pins (ignition on, of course).
The sender element is basically just a potentiometer. The wiper voltage should vary from zero to 5 volts as the float is moved up and down."
So it's okay to test these things with the unit out of the tank? I had this concern that powering it up might get the pump sucking air or something. Hope that's not too stupid. As I said in the previous post, I'm making a concerted effort to learn about these things but I'm not there yet.
The sender element is basically just a potentiometer. The wiper voltage should vary from zero to 5 volts as the float is moved up and down."
So it's okay to test these things with the unit out of the tank? I had this concern that powering it up might get the pump sucking air or something. Hope that's not too stupid. As I said in the previous post, I'm making a concerted effort to learn about these things but I'm not there yet.
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"The cluster sends 5 volts to the sender element, so there should be 5 volts on one of the connector pins (ignition on, of course).
The sender element is basically just a potentiometer. The wiper voltage should vary from zero to 5 volts as the float is moved up and down."
So it's okay to test these things with the unit out of the tank? I had this concern that powering it up might get the pump sucking air or something. Hope that's not too stupid. As I said in the previous post, I'm making a concerted effort to learn about these things but I'm not there yet.
The sender element is basically just a potentiometer. The wiper voltage should vary from zero to 5 volts as the float is moved up and down."
So it's okay to test these things with the unit out of the tank? I had this concern that powering it up might get the pump sucking air or something. Hope that's not too stupid. As I said in the previous post, I'm making a concerted effort to learn about these things but I'm not there yet.
When I tested mine I opened the hatch so I could see the instrument panel better and then moved the float arm to see how the fuel gauge reacted. It has a delay built in to avoid the gauge jumping around when the fuel sloshes in the tank, so it takes a few seconds for the gauge to reflect what the float arm is doing.
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Okay. What I'm thinking of doing is scrape/dremel the ground contacts off the housing (by that I mean the plate at the top where the inlet is), clean things up and - what? - solder the ground(s) onto clean metal? Feasible? Sensible?
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