Does anyone know what the trick is to replacing the sending unit in a 82 Corvette? I have ordered the replica units from two major Corvette suppliers and neither of them will work. My original Unit has some kind of small capacitor looking thing that is mounted on the pick-up tube. The replacements do not have this and the Fuel pump will not operate. The real kicker is Ecklers and Mid-America say they have no idea what its for. I can replace the fuel pump on the original sender and it works but my problem is the gauge does not work. Even the auto parts stores in town do not know what the capacitor thing is. All I know is the so called exact replica parts do not have it and do not work in my car. Any help would be appreciated.

 

I will have to ask my buddy who also has an 82 and replaced his sending unit not to long ago, will try to contact him within the next day or so and get the info. Maybe another member may have the info you need before I can back to you......Tom

 

The part that you are talking about is not needed...because later years do not have it. It is used to suppress the noise from the pump running and getting into the speakers when the radio was playing. SO...it has nothing to do with the fuel pump not working. I bet you do not have a good wire going from the pump to the connector you clip into on the body wiring. You have to remember...there is a bulkhead connector attached where the wiring goes into the fuel side of the sending unit.

Also..DO NOT ASSUME that the wires are connected correctly in the connector that clips into your factory body wiring.

This is easy to check. Disconnect the connector to your new pump and with a helper...have them turn your key on and see if you get 12 volts to the power wire going to the pump...and ground on the other...by using a volt meter...NOT a test light.

DUB

 

Dub thanks for the information. I was wondering if this might be some kind of radio static suppression device. I still don't under stand why the replacement units do not work. Like I said my original fuel pump works just fine. The sending unit is the problem. I took both of the replacement units and plugged them in. I can lift the float arm up and down and get a reading on my fuel gauge but the fuel pump on both units would not work. I am still using my original unit but I have no fuel gauge because the sender is bad. I even put my fuel pump on one of the replacement units and it would not work. So you think the wiring on the replacement units is backwards or something. I know I'm getting power to the plug because my original pump works.

 

On some cars that capacitor thing is actually a suppressor for the fuel gauge. So it moves slowly rather than flopping up and down with the gas in the tank.
Idk if our vettes have it, I have not had to do my 82 yet.

 

I'm planning on using an 82 sending unit in my 80 for a tpi conversion. Please let us know what works for you!

Thanks, Dega

 

You have to understand that it does not matter IF the fuel gauge works. The fuel gauge reading is only ONE circuit...and has ABSOLUTELY nothing to do with the fuel pump running. If you understand that. Then it has to do with the wiring as I wrote in my last post. Using your original as a tester. Check to make sure the wires from the connector to the pump are in the SAME location in the 3 wire connector. Knowing that it is aftermarket...I would plug it in...turn your key on with the PUMP NOT CONNECTED,,,and see if you get 12 volts to the end of the connector that attaches to you fuel pump. IF you don't...then either you are not getting a good connection from the body wiring...or the interface where the wires go through eh sending unit are not making good contact.

Yes I believe it has to do with the 12 volts getting to your connector for your new fuel pump in the new unit. You can have 12 volts at the end of the factory plug in the body wiring...but if the current can not make it to your connector at your fuel pump...it will not work. And this also applies to the GROUND circuit.

One thing to keep in mind. That if you use a voltmeter and are checking a circuit that is NOT working. And when you go and check the circuit with the voltmeter and it shows that 12+ volts is present as it should be. That does not ALWAYS mean that it will work.

The reason being: AMPS.

You can use a car speaker wire and go from your battery to the starter. It will carry 12+volts. It will OHM out correctly,,,and show continuity. BUT...when you go to crank your car...the gauge of the wire (being so small) CAN NOT handle the AMP LOAD that the starter needs to operate...thus melting down the small speaker wire. So..this is why the wire/cable to your starter is so large. So it can carry and handle the severe amp load when the starter is being used. SO..using this know fact. Your wire in your new sending unit may have 20 strands to make up that gauge of wire(for example). Which if they all are not broken..can carry the load that the fuel pump will require to operate. BUT...if 18 out of the 20 are broken...those 2 strands can not carry the load and will fail...BUT...when you test for volts, ohms and continuity...it will show to be "good"...because it is good... because you still have wires going form "A" to "B".

SO...IF EVER you have a wire that is in question of its gauge integrity (broken stands within). I remove/disconnect BOTH ends of the wire in "question". I then use a high/low beam headlight and wire it so BOTH high and low beam will burn when energized to ONE END of the wire in question. This wire in question, on the OTHER END will be attached to a 12 volt power source. IF the headlight will burn...the same as if you hooked up the headlight to your battery directly...then the wire is good. IF it does not work or is dim...then the wire is bad...this also is ASSUMING that you connected it correctly and secure and the ground is also connected well.

This procedure has saved me more times than I can count over the years.

DUB

 

Thanks for the additional info. Dub. I do understand that the sending unit and the pump are two separate circuits. Both replacement units were purchased from reputable Suppliers. One from Ecklers and one from Mid-America. I'm sure they are both foreign made but don't know if they came from the same manufacturer. When I get more time I will order another unit and do the test you are speaking of. Until then I will just keep driving with no fuel gauge and fill up every 200 miles. It is a hassle pulling the unit out over and over and it usually destroys the tank gasket when you pull it out. The part should be ready straight out of the box. I've never had trouble with GM parts like this but this unit is no longer available from them.

 

I already did this for my EFI set up and did not have a problem.