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Discussion Starter #1
Hey everyone. I have installed a brand new fuel cell in the trunk with fuel sender, that I purchased from summit. I also installed a new M&H harness that goes from under the column to the rear of the car, lights et cetera.
I have the tan cable from the harness connected to the terminal "S" on the fuel cell. I also have a ground cable going from the only other terminal of the cell to a ground in my tank.
The gauge up front is not reading the fuel level. It stays on empty.
Any ideas? Everything else works fine with the new harness (dome light, rear lights, have not hoocked up the reverse lights yet.)
Thanks. The car is '68 Chevelle by the way.
 

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is there not a way to check the sending unit using an Ohm meter? i believe it must be set to specific range to work with our cars. still have the instructions??, my neighbor is having me help him because his new sender says something about checking it and setting it to a specific range, since i have multimeters and know how to use them i'll be doing it for him, just not sure how to do it yet. (car is torn apart for paint currently and tank is out while new pan is put in)

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GM sending units are 0-90 ohms, you can test it with a DVM. Make sure you have a good ground wire from the sending unit ground to the car, as well as the harness ground to the car.

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66 chevelle ss396 hdp/conv
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Discussion Starter #4
No instructions?? It was a summit cell and the only instructions were on how to mount the cell.
It is supposedly a 0-90 sender, how do I measure? Assuming 0 ohms at full, 90 empty?
Also, what do you mean by a ground from the harness to the car? I just grounded one of the 2 terminals on the sender at the top of the cell to the car.
Thanks guys.
 

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<BLOCKQUOTE>quote:</font><HR>Originally posted by yanniz:
No instructions?? It was a summit cell and the only instructions were on how to mount the cell.
It is supposedly a 0-90 sender, how do I measure? Assuming 0 ohms at full, 90 empty?
Also, what do you mean by a ground from the harness to the car? I just grounded one of the 2 terminals on the sender at the top of the cell to the car.
Thanks guys.
<HR></BLOCKQUOTE>
The other way 88-90 ohms is full. 0 ohms is empty. Sounds lke you hooked it up ok. How much fuel did you add to the cell?
 

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Discussion Starter #6
About 3 gallons, it is a 16 gallon tank. I guess I better add some more in case.

I also tried to ground the sender by touching the "S" terminal with the ground terminal and nothing happened.
 

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Is it the 16 gallon pro street cell with sump. if so, it wont start to read until you put about 4-5 gallons in it. i've got the same cell in my monte and when the cell is full, the needle says a little over 3/4, once it hits empty, have still got about 4 gallons left. i guess its hard to get the sender to read right in a cell with a sump. hope this helps.
 

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Discussion Starter #8
I do have this cell, but the problem is that when I ground the "S' terminal the gauge just sits there.
Thanks.
 

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<BLOCKQUOTE>quote:</font><HR>Originally posted by yanniz:
I do have this cell, but the problem is that when I ground the "S' terminal the gauge just sits there.
Thanks.
<HR></BLOCKQUOTE>
Yanni
Don't ground the "S" terminal. Won't hurt but won't tell you anything. Measure the "S" terminal to frame ground with a meter. (wire off) Reading is 0 ohms for empty, 90 ohms for full, 44 ohms for half tank, and maybe somewhere around 20 ohms for your 1/4 tank.
The sensor is just a moving resistor like thing.
 

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ok, first make sure the sender is working, by making sure the ground is good and the other wire is connected to your harness and it's continuant to the guage. (i assume you've already done this) now take a ohm meter and touch the 2 terminals on the outside of the cell where the wires connect, and use a metal rod to raise/lower arm of the sending unit the ohms should change they will go up as the arm goes up, if this works then it's somewhere between it and the fuel guage. and we can go from there, i've posted a few pics of mine just a FYI i just took and measured 20ohms and 1/4th tank or so key off just measured ohms between terminals. http://members.aol.com/jnkb2cool/sender.jpg

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Discussion Starter #12
Ok, I measured acrooss the 2 terminals (S and ground) and it gives me a 1.5 ohms with 1/4 of the tank full.
I did not take the sender out to do as John said but this reading indicates that the sender is bad! Does this make sense?

P.S. By the way those dual Winstar fans look great and they sure pull a lot of air. I wired one to run constant (it is right behind the radiator and tranny cooler) and the other to a 180/160 thermostat.
 

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<BLOCKQUOTE>quote:</font><HR>Originally posted by yanniz:
Ok, I measured acrooss the 2 terminals (S and ground) and it gives me a 1.5 ohms with 1/4 of the tank full.
I did not take the sender out to do as John said but this reading indicates that the sender is bad! Does this make sense?
<HR></BLOCKQUOTE>
That John should learn to write a little clearer. What I suggested was disconnecting the tan wire off the sensor before you take the measurement. Only measure the sensor itself to ground.
Someone suggested that the fuel cell doesn't respond or gives an empty reading when it really has 4 gallons in it due to the sump. This might be why it is not responding yet.
 

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ok, which john should write clearer??? me, ok i'll make it ez, just touch the terminals with the ohm meter, at the same time raise the sending unit arm and see if the ohms go up. no need to disconnect it. just make sure the key is off.

if it works then just adjust the arm so it's down more in the tank,should just be a bolt/nut to loosen and adjust it down. if it's showing 1.5 then i'd think it'll work, just needs adjusting.
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[This message has been edited by chev-hell (edited 11-22-2001).]
 

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<BLOCKQUOTE>quote:</font><HR>Originally posted by chev-hell:
ok, which john should write clearer??? me...
<HR></BLOCKQUOTE>
No me. Just commenting about my poor typing again.
 

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Discussion Starter #16
Ok guys. Something really weird is going on.
John, I took the tan wire of the sender post and measured the post to the frame ground, and I got about 8.5 ohms. Once I put the wire back, my gauge went up to little less than 1/4!!

One of 2 things happen. Either I am totally stubid and I was measuring before with the braker attached to my battery disconnected, or something happen during that measurement from the S post and ground that made it work.

For now, I will assume that it works, and I will get some more gas in to see if the gauge reacts.

Thanks for your help guys.
 
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