Fuel Gauge still reading barely above empty - The 1947 - Present Chevrolet & GMC Truck Message Board Network

70c10 · 11-28-2004, 06:08 PM

If I disconnect the sending unit wire from the fuse panel it reads way past full-
If I connect the wire from the sending unit wire to the fuse panel it reads 1/8.

This is what I have done:
1. Install a brand new sending unit.
2. Install brand new wire from sending unit to fuse block.
3. Ran a continuity test from both tan wires at ignition to cluster plug and fuse block.
4. Ran continuity test from tan wire at cluster plug to fuse block.
5. Tried 4 seperate fuel gauges and resistors on the back of the gauge.
6. Touched the back of the gauge with a test light and it had current.
7. Don't know if this was stupid or not( touched both terminals on the back of the gauge and it shot the gause needle up way past full while making a noise).
8. I pulled the new brass float off the sending unit and submerged it in water and saw some bubbles and could hear water sloshing in it. (obviously a pin hole).
I wanted to solder it but was afraid the gas in it might ignite.
Would a pin hole cause the gauge to read 1/8?.
If so, how should I remove the liquid in the float?. Sorry for the loooong post!

cableguy0 · 11-28-2004, 06:11 PM

your problem is the float its sinking in the gas tank and the trapped air is holding it to an 1/8 tank. get a new float and your problem will be gone

70c10 · 11-28-2004, 06:37 PM

Jason, I hope that's all it is. The float is brand new!. I still have the old float I can probably use and add a new layer of solder and try it!

Sweet72 · 11-28-2004, 06:44 PM

If you're interested in repairing it, just drill a 1/16" hole in the opposite end of the pin hole and drain it. Make sure it's dry inside before attempting to solder. You should have no problem soldering it with a pencil type iron and whatever lead / tin solder you have on hand. I have a used float you can have if you're interested.

cableguy0 · 11-28-2004, 06:52 PM

i should have one extra one too jim its from a 69 truck sending unit and all but i think its a 6 cwl sending unit

70c10 · 11-28-2004, 07:01 PM

Thanks guys,
Let me check the old float and see if it's useable first. I appreciate the offers. I hate the fact the unit is brand new and I have to repair it!. It was sitting new in the box for 2 years.

cableguy0 · 11-28-2004, 07:10 PM

thats pretty sh!tty in my opinion. i hate new parts that are bad

Huck · 11-28-2004, 09:41 PM

Most auto parts stores carry the float as it is a very common piece for most vehicles---and cheep to----not worth the hassle to repair---.

Harold Shepard · 11-28-2004, 09:55 PM

I went through two new floats and a used one before I got my gauge to work. Everyone of them had a pin hole of some type. I have had better luck w/ GM than the reproduction floats.

70c10 · 11-28-2004, 11:59 PM

Glad to hear I can get a new one locally if I have to.

70c10 · 12-01-2004, 12:27 AM

I got it fixed tonight. It was the float. Luckily I saved the old one!

11-28-2004, 06:08 PM	#1
70c10 67-72 Addict! Join Date: Feb 2002 Location: The TAX State! Posts: 7,856	Fuel Gauge still reading barely above empty If I disconnect the sending unit wire from the fuse panel it reads way past full- If I connect the wire from the sending unit wire to the fuse panel it reads 1/8. This is what I have done: 1. Install a brand new sending unit. 2. Install brand new wire from sending unit to fuse block. 3. Ran a continuity test from both tan wires at ignition to cluster plug and fuse block. 4. Ran continuity test from tan wire at cluster plug to fuse block. 5. Tried 4 seperate fuel gauges and resistors on the back of the gauge. 6. Touched the back of the gauge with a test light and it had current. 7. Don't know if this was stupid or not( touched both terminals on the back of the gauge and it shot the gause needle up way past full while making a noise). 8. I pulled the new brass float off the sending unit and submerged it in water and saw some bubbles and could hear water sloshing in it. (obviously a pin hole). I wanted to solder it but was afraid the gas in it might ignite. Would a pin hole cause the gauge to read 1/8?. If so, how should I remove the liquid in the float?. Sorry for the loooong post! __________________ Jim 1970 C/10 Fleetside w/Ghost Flames Lowered 4.5" front and 4" rear (Raked) 355/350 Turbo w/shift kit 10" Redneck Performance Verter w/2500 stall Hooker Super Comps part#2808-1 Performer RPM Air-Gap 12 Bolt w/3:73 gears- Eaton Posi Comp Cams XE262 with 1.6 Crane Energizers, Road Demon 625 and Brodix IK 180 heads

11-28-2004, 06:11 PM	#2
cableguy0 Senior Member Join Date: Apr 2000 Location: Delta,Pa Posts: 14,948	your problem is the float its sinking in the gas tank and the trapped air is holding it to an 1/8 tank. get a new float and your problem will be gone __________________ Owner of North Point Car Care in Dundalk Md. We specialize in custom exhaust on both modern and classic vehicles. We are a full service auto shop from classics to modern vehicles. Feel free to contact me with questions. I will give a 10% discount to any board member.

11-28-2004, 06:37 PM	#3
70c10 67-72 Addict! Join Date: Feb 2002 Location: The TAX State! Posts: 7,856	Jason, I hope that's all it is. The float is brand new!. I still have the old float I can probably use and add a new layer of solder and try it! __________________ Jim 1970 C/10 Fleetside w/Ghost Flames Lowered 4.5" front and 4" rear (Raked) 355/350 Turbo w/shift kit 10" Redneck Performance Verter w/2500 stall Hooker Super Comps part#2808-1 Performer RPM Air-Gap 12 Bolt w/3:73 gears- Eaton Posi Comp Cams XE262 with 1.6 Crane Energizers, Road Demon 625 and Brodix IK 180 heads

11-28-2004, 06:44 PM	#4
Sweet72 Registered User Join Date: Nov 2003 Location: Alexandria, VA Posts: 1,534	If you're interested in repairing it, just drill a 1/16" hole in the opposite end of the pin hole and drain it. Make sure it's dry inside before attempting to solder. You should have no problem soldering it with a pencil type iron and whatever lead / tin solder you have on hand. I have a used float you can have if you're interested. __________________ '72 GMC SWB C1500 Custom, frame-off in progress. 383 SBC, 9:1CR, Comp Cams XE262H, Scat internal balanced crank, Eagle SIR 6" rods, Keith Black dish pistons, Dart Iron Eagle 72/180 heads, Weiand Stealth intake, Stewart stage I water pump, Holley 4bbl vac sec, TH350 with B&M Shift Improver Kit. 12 bolt positraction.

11-28-2004, 06:52 PM	#5
cableguy0 Senior Member Join Date: Apr 2000 Location: Delta,Pa Posts: 14,948	i should have one extra one too jim its from a 69 truck sending unit and all but i think its a 6 cwl sending unit __________________ Owner of North Point Car Care in Dundalk Md. We specialize in custom exhaust on both modern and classic vehicles. We are a full service auto shop from classics to modern vehicles. Feel free to contact me with questions. I will give a 10% discount to any board member.

11-28-2004, 07:01 PM	#6
70c10 67-72 Addict! Join Date: Feb 2002 Location: The TAX State! Posts: 7,856	Thanks guys, Let me check the old float and see if it's useable first. I appreciate the offers. I hate the fact the unit is brand new and I have to repair it!. It was sitting new in the box for 2 years. __________________ Jim 1970 C/10 Fleetside w/Ghost Flames Lowered 4.5" front and 4" rear (Raked) 355/350 Turbo w/shift kit 10" Redneck Performance Verter w/2500 stall Hooker Super Comps part#2808-1 Performer RPM Air-Gap 12 Bolt w/3:73 gears- Eaton Posi Comp Cams XE262 with 1.6 Crane Energizers, Road Demon 625 and Brodix IK 180 heads

11-28-2004, 07:10 PM	#7
cableguy0 Senior Member Join Date: Apr 2000 Location: Delta,Pa Posts: 14,948	thats pretty sh!tty in my opinion. i hate new parts that are bad __________________ Owner of North Point Car Care in Dundalk Md. We specialize in custom exhaust on both modern and classic vehicles. We are a full service auto shop from classics to modern vehicles. Feel free to contact me with questions. I will give a 10% discount to any board member.

11-28-2004, 09:41 PM	#8
Huck Senior Member Join Date: Jun 2001 Location: Shelbyville, KY Posts: 3,261	Most auto parts stores carry the float as it is a very common piece for most vehicles---and cheep to----not worth the hassle to repair---.

11-28-2004, 09:55 PM	#9
Harold Shepard Registered User Join Date: May 2004 Location: Canton North Carolina Posts: 466	I went through two new floats and a used one before I got my gauge to work. Everyone of them had a pin hole of some type. I have had better luck w/ GM than the reproduction floats.

11-28-2004, 11:59 PM	#10
70c10 67-72 Addict! Join Date: Feb 2002 Location: The TAX State! Posts: 7,856	Glad to hear I can get a new one locally if I have to. __________________ Jim 1970 C/10 Fleetside w/Ghost Flames Lowered 4.5" front and 4" rear (Raked) 355/350 Turbo w/shift kit 10" Redneck Performance Verter w/2500 stall Hooker Super Comps part#2808-1 Performer RPM Air-Gap 12 Bolt w/3:73 gears- Eaton Posi Comp Cams XE262 with 1.6 Crane Energizers, Road Demon 625 and Brodix IK 180 heads

12-01-2004, 12:27 AM	#11
70c10 67-72 Addict! Join Date: Feb 2002 Location: The TAX State! Posts: 7,856	I got it fixed tonight. It was the float. Luckily I saved the old one! __________________ Jim 1970 C/10 Fleetside w/Ghost Flames Lowered 4.5" front and 4" rear (Raked) 355/350 Turbo w/shift kit 10" Redneck Performance Verter w/2500 stall Hooker Super Comps part#2808-1 Performer RPM Air-Gap 12 Bolt w/3:73 gears- Eaton Posi Comp Cams XE262 with 1.6 Crane Energizers, Road Demon 625 and Brodix IK 180 heads



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