No reading on Gas Gauge, What to do??

[prayers1 153]

When I installed my tank, the inside and outside of the trunk was sparyed with an under coating, then I used strip chaulk to insulate the tank. Do you think I may of lost some of the ground?

 

I've noticed that GM uses a direct ground wire from the sending unit. Should I put a seperate ground strap from a spot where the tank bolts in and then to the body.

 

I have some time to work on it today, any other suggestions.

 

Thank you!

[69RavenConv 286]

When I installed my tank, the inside and outside of the trunk was sparyed with an under coating, then I used strip chaulk to insulate the tank. Do you think I may of lost some of the ground?

 

Probably not. I also used strip caulk. The many sheet metal screws that secure the tank to the chassis should bite into bare metal on both surfaces and provide a good ground.

[prayers1 153]

I agree, but I used 5/16s galvanized nut and bolts.

[det0326 179]

OK, then why didn't the gauge read empty when the key was turned on. It actually went 1/8th higher than before. See post #45

 

If you disconnect the wire at the sending unit and turn the ignition switch on, does the gauge stay the same or does it go to empty?

[prayers1 153]

I CAN'T BELIEVE WHAT I FOUND!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

 

I took the tank out and found a ton of rust/chunks inside the tank, covering all the walls and on the sending unit. The sending unit was frozen to almost empty. No wonder why, I couldn't figure out the electrical end of it.

 

I had a NEW Holley Street Avenger, fuel pump, Chrome filter, fuel lines from tank to carb, tank & sending unit and fresh motor installed prior to dropping the car off at the bodyshop 12/2011.

 

I recently received the car and started driving it, the first day it died in traffic from fuel starvation. I recently had to replace the fuel pump, new line & filter to carb. I took the carb off and sent it to Holley. While the car was at rest, I decided to tackle the fuel gauge problem and now find why the fuel starvation happend and why the fuel gauge wasn't working.

 

I purchased the tank/sending unit from CJpony on 10/10/11. I contacted them today and they want documentation. I emailed pics and copy of Invoice.

 

Edited October 14, 2013 by prayers1

[Midlife 814]

Holy crap! That level of rust shouldn't happen in 2 years time, even with ethanolated gas. I believe your grounding issue with seam sealer may be contributing, as it is possible that the sending unit is acting as an anode. Although I agree that the mounting screws are usually good enough for grounding the tank to the chassis, it might be worthwhile considering a companion grounding strap.

[69RavenConv 286]

Holy crap!

 

+1 :ohmy: You'll get condensation inside an empty tank but I never thought it would do that much damage, that fast. Looks like you found the problem.

[prayers1 153]

When I received the car back about a couple of months ago, the tank was partically screwed in with the oem type screws, just laid on top of the metal of the car. It was agreed at the shop that I would finish the tank installation.

 

In fact I started a thread here on 8/18/13 on what best to do for sealing the tank. Thats when is was suggested to use the seam chaulk. So, it hasn't been that long that there was a ground issue, if there was one to cause this excessive rust.

 

I believe it's some type of overseas cheap metal that used.

[prayers1 153]

Any opinions on what to do, would this be a warranty issue?

[det0326 179]

Any opinions on what to do, would this be a warranty issue?

 

Wouldn't hurt to try I guess but IMHO that amount of rust your talking about had to come from water in the tank. Do you think maybe your body shop took the tank out for some reason and left it out side? I just don't see how all this rust accumulated without being exposed to the elements.

Really glade you found you problem but it is bad that it had to be already replace parts that sucks.

Dave

[prayers1 153]

CJpony was kind enough to replaced free of charge the tank and sending unit. I applied that money to a SS tank and sending unit. While waiting for the parts, I purchased a solid state CVR, I also sent the Carb to Holley where is was rebuilt. The carb came back before the Tank, so I rejetted it to 56/67 and changed the power booster to 5.5.

 

After everything was installed, the car fired up and ran great!! The gas gauge works, but the only problem is that when the gauge is close to E it has 5 gallons, when at 1/4 it had 10.

 

Thank you to all for your help & opinions!

[manley 13]

If you had the wrong sending unit, possibly for an earlier year, would this incorrect fuel gauge reading result? Would bending the arm help?

[Chris'69Mach 23]

CJpony was kind enough to replaced free of charge the tank and sending unit. I applied that money to a SS tank and sending unit. While waiting for the parts, I purchased a solid state CVR, I also sent the Carb to Holley where is was rebuilt. The carb came back before the Tank, so I rejetted it to 56/67 and changed the power booster to 5.5.

 

After everything was installed, the car fired up and ran great!! The gas gauge works, but the only problem is that when the gauge is close to E it has 5 gallons, when at 1/4 it had 10.

 

Thank you to all for your help & opinions!

 

LOL ... just the oposite here.

 

Gauge reads full, it has 10 gallons, reads 1/2 it has 5. Everything to include the gas cap to the carb (new holley 770 carb) has been replaced. Getting 10-11 MPG on 93 octaine.

 

She runs sweet as hell and pins my ears back when the hammer hits the floor! :thumbup:

[Midlife 814]

You can adjust the readings on the gas gauges by adjusting the CVR. Somewhere on the back is a trim-pot covered in epoxy. Break the epoxy and then turn the trim pot such that when you have a true 1/4 tank of gas (4 gallons?), make the gauge read 1/4 full. This will also affect your oil and water temperature gauges, as all three are controlled by the CVR.

[det0326 179]

CJpony was kind enough to replaced free of charge the tank and sending unit. I applied that money to a SS tank and sending unit. While waiting for the parts, I purchased a solid state CVR, I also sent the Carb to Holley where is was rebuilt. The carb came back before the Tank, so I rejetted it to 56/67 and changed the power booster to 5.5.

 

After everything was installed, the car fired up and ran great!! The gas gauge works, but the only problem is that when the gauge is close to E it has 5 gallons, when at 1/4 it had 10.

 

Thank you to all for your help & opinions!

 

What does it do when you fill it up?

I don't know if I would even worry about it because if you only have

5 gallons when it gets to the E its time to get more gas.

Glade you have it fixed and that CJP warrantied your tank and sender.

So I guess if you are going to replace the tank its best to go with

the stainless steel one. Which I will probably be doing when I get to that point.

[det0326 179]

LOL ... just the oposite here.

 

Gauge reads full' date=' it has 10 gallons, reads 1/2 it has 5. Everything to include the gas cap to the carb (new holley 770 carb) has been replaced. Getting 10-11 MPG on 93 octaine.

 

She runs sweet as hell and pins my ears back when the hammer hits the floor! :thumbup:[/quote']

Yours could be fixed rather easy if you wanted to trim it in a little. You

could actually put a resistor in line with the wire that goes to the sender

you may have to do a trail and error till you find out what resistance you

would need . I would guess maybe 10 - 20 ohms would be a good place to start. Prayers1 could not do this since his is opposite.

[Chris'69Mach 23]

Yours could be fixed rather easy if you wanted to trim it in a little. You

could actually put a resistor in line with the wire that goes to the sender

you may have to do a trail and error till you find out what resistance you

would need . I would guess maybe 10 - 20 ohms would be a good place to start. Prayers1 could not do this since his is opposite.

 

I agree .... a friend of mine said he wouldlike to put a resistor in line to fix this. He is a bit geeky and is very knowledgeable in electrical things. I am more mechanically inclined .... pretty good match to be putting this car together.

[prayers1 153]

I think I'll leave everything as it is. I got it to a point that I can finally drive the car, now I can address other issues. As long as the gauge is reading and registering 5 gal. on E, I'll never run out of gas, I'll just keep filling it up when it gets to that point.