[studeman]

I want to put a 69 Camaro fuel tank in my 52 Chevy truck. I have questions about the sending unit. What are the two hard lines on the sending unit for? One is clearly for the fuel but the other I don't know. Also does anyone know if this unit will work with my stock guages in the 52? I will be running a carbureted 350 with a stock mechanical pump. I am new here and can use all the help I can get. thanks guys.

[Deuce]

WELCOME to Hotrodders.com.

One line is for a return line ... the other is a feed line.

The sending unit is 12V ... and a original 52 fuel gauge was 6V

Deuce ...

[docvette]

Doc here,

Welcome Aboard!

Confused here..

Are you talking Electrical when you say "hardlines" or plumbing???

The sender in your 69 Camero Tank is a resistive device , referenced to ground...

It is a variable resistor or linear taper, MECHANICALLY mounted to a float device submersed in the media..As the level of the media increases or decreases, the float follows suit, ergo the movable contact on the variable resistor..The resistor is a 3 tab device with 2 stationary posts and a movable contact.

One stationary post will be total resistance of the device referenced to ground..(in most systems this is empty)

The other stationary post is referenced to ground or ground potential. (in most, this is full)

The Movable contact is the wiper in the center that travels between the two stationary posts, and reports the resistive load back to the gauge.

Think of it as a Volume Control on an old radio or TV, (before remote days. ) As you turn the control clockwise it gets louder..as you turn it counter clockwise, the volume goes down..NOW extend the knob to an ARM with a FLOAT on it , in a media..Same result.

The Key to interface is the total resistance of the Sender Vs Total resistance of the gauge. On a system that old I would think the Gauge is a 0 to 30 ohm sender input..and a 69 camero sender MAY also be a 0 to 30 ohm sender..Both must be on the same page to accurately operate , or even function..Here .. Voltage IS NOT an issue..(only at the power to the gauge..the sender does not care..)

So If your gauge is 0 to 30 Ohms..your sender must also be 0 to 30 ohms. To test the sender, remove it, and with your DVOM set for OHMS scale, R X 1, calibrated to 000, place one probe on the sender body, (Ground) and the other probe on the sender terminal..note the reading..It should be 000, or 30 ohms (depending on how the system was wired) If , for instance , It is 000, slowly move the float up..and watch the meter..It should read a steady increase in resistance to to , Say 30 ohms..With that reading, you know two things..It is a 0 to 30 ohm sender...AND it is operable.

If the readings "jump" all over the place or drop in and out, the resistive device is worn past runout..and the sender needs replacement. It should be a steady change if done slowly.

Never put 12 volts on a sender line... UNLESS you wish to run the risk of a crater where your fuel tank used to live..One Spark in a device immersed in 30 gallons of explosive media can result in tragedy..

Your wires coming off the sender are One wire coming from the Tank ground (or ground lug on the fuel pickup/Sender Egress panel) , and the other is the sender wire itself...

This wire will go to the gauge sender terminal Or "S" terminal.

The other will go to hard ground at the frame..Burnish off all the paint and oil, and dirt from that area, add a star and lock washer, and screw or bolt tightly.

If the Resistance matches, your gauge should work totally fine..

Doc

[studeman]

Thanks guys for the replies. I will look into the ohm reading on the stock gauge. if you have any ideas as to how to do that I am all ears. I will look myself as well. As for the return line on the sender(hard line that carries fuel) is it necessary for my application? Can I just block it off. The tank will have a vented cap. Thanks for all your help.