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Discussion Starter #1
I just acquired an intank fuel pump/sending unit assembly from a z28 camaro. Winter project is to replace my frame mounted pump with the camaro unit.

I was checking to see if it all worked, seemed to. But, I noticed that the resistance of the sending unit SEEMS different than on my el camino.
This is from my half-timers effected memory, but I think that the elky unit goes from 0-90 ohms. The camaro unit SEEMED to go from about about 90-135 ohms. I haven't done any cleaning etc, but the question is:
Are the later year sending units different?

If they are the same, I'll clean it up, if they are definitely different, I'll try to adapt the elky unit.

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Rick
72 El Camino
TPI350/700r4
TC#00038
ACES#00140
 

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All of the "horsepower era" sending units were 90 ohms, meaning a range of about 0 ohms to about 90 ohms.

To be honest, I'm not sure if they changed the later stuff, it wouldn't suprise me if they did.

If indeed, the "modern" unit you have does NOT have the 0-90 ohm range, it will NOT work with your original style gas guage.

Joe

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So this transistor and a vacuum tube walk into a bar...
 

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Can't say for sure on your year, but I used a '96 Z28 tank unit on my '70 Chevelle and the sender ohm range was different. Therefore, I had to fabricate the '70 fuel gauge sender onto the '96 tank unit bracket.

Craig Berland
 

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Joe'd right except for the 64 Chevelle. That one has a 0-45 ohm unit. Ran into the problem when I wanted to replace the 5/16 one with a 3/8. You can find 64 5/16 senders but no one carries the 64 3/8.
Ended up buying a 65 3/8 sender (about 88 ohms) and shunting the meter between the sender input and ground. Used a standard 39 ohm resistor.
No ohm's law lessons please. Played with different values and watched meter response. If you try and use a 88 ohm shunt, the fuel gage remains high and drops like a rocket in the lower part of the meter.
John
 

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Discussion Starter #5
J-C-J
thanx for the input. C- From your post a few weeks ago (hi-tech) I suspected as much. I've seen in mom/pop parts stores, repair resisters for guages etc. I think that I will check for a tank unit resister. See if I can "make it work" - like most everything else on my car
.

J-I know ohms law, I used to watch him on TV - oh no that was Burkes Law.

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Rick
72 El Camino
TPI350/700r4
TC#00038
ACES#00140
 

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I'm not positive, just going on aftermarket gauge specs, GM senders come in two flavors. I don't know the exact specs, but every thing prior to 64 or 65 is one I think 0-30 or 50 something like that, and everything after that is the same 0-90. The numbers may not be correct, but there are supposedly only two ranges of senders it should work. I'm putting a '94 intank pump & sender in to my '68 Elky. I guess we'll find out soon enough. Mine should be running this week. (fingers crossed)
L8tr,

Wes O.

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"When the job gets you down, and life's a drag,..........RACE!!"

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The Project Begins! Watch as it progresses at: My '68 El Camino Project
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