fuel sending unit - The 1947 - Present Chevrolet & GMC Truck Message Board Network

SnS C10 · 11-28-2004, 09:23 PM

i tried to hook up my gas gauge awhile ago and when it was hooked up, the needle always went past full. when it was unhooked, it read empty. so i tried a vdo gas gauge, hooked up a power wire and ground wire and the sending unit wire and it still didnt work. so u guys think i just need a new sending unit or is there something else that u guys recommend i do? thanks. i was just thinkin i will buy a new sending unit but would like to hear your suggestions

JimKshortstep4x4 · 11-29-2004, 09:07 AM

Can you clarify on what happens when the gauge is hooked up or unhooked up?

You said tha when it is hooked up it reads past full but unhooked it read empty. The gauge really should just do the opposite.

Jim

70c10 · 11-29-2004, 09:36 AM

Jim is correct. I am going thru this as we speak. It sounds like your problem is a broken wire. Run a new wire from the sending unit to the fuse block and see if it fixes it. My problem is the opposite (always on empty unless I unplug it)and I have found a pinhole in the float. I will be replacing it one evening this week and will report back with the results.

SnS C10 · 11-29-2004, 07:46 PM

actually i checked it out again and when i unhook the sending unit wire, the gauge reads past full. it does the same on my new vdo gas gauge. so i replaced the wire to see if the wire is bad. it did the exact same thing with a new wire. so im gonna be ordering a new sending unit, thanks guys

Brainchild · 11-29-2004, 08:01 PM

I have successfully taken the sender apart,and cleaned the contacts inside and it work.I did it on the 71 I am now driving.
All I did was bend the little tabs out with a small screwdriver,enough to allow the square box,with the float arm through it to come off,and then clean the inside of the sender with some contact cleaner,and put it back together,and it works great.If it's just dirt could save ya some $$$.I mean ya gotta order one anyway

Be careful not to break the tabs off,they are really small

You can ground the unit,and plug the wire into the sender,and move the float arm to test it.

Robert1970C20rstbukt · 11-29-2004, 08:14 PM

I did the same thing Branchild did, I just cleaned mine out. It had yellow-green corrosion all inside it so I sprayed some LPS industrial contact cleaner on it, put it back together and it worked like it should.

Blue Beard · 11-29-2004, 09:09 PM

Don't mean to hi-jack a thread but this is along the same lines.

Any help with a dual tank setup.....no matter which tank is switched on only reads 1/4 tank when full...

11-28-2004, 09:23 PM	#1
SnS C10 Registered User Join Date: Jul 2004 Location: Lomita, Ca Posts: 1,225	fuel sending unit i tried to hook up my gas gauge awhile ago and when it was hooked up, the needle always went past full. when it was unhooked, it read empty. so i tried a vdo gas gauge, hooked up a power wire and ground wire and the sending unit wire and it still didnt work. so u guys think i just need a new sending unit or is there something else that u guys recommend i do? thanks. i was just thinkin i will buy a new sending unit but would like to hear your suggestions

11-29-2004, 09:36 AM	#3
70c10 67-72 Addict! Join Date: Feb 2002 Location: The TAX State! Posts: 7,857	Jim is correct. I am going thru this as we speak. It sounds like your problem is a broken wire. Run a new wire from the sending unit to the fuse block and see if it fixes it. My problem is the opposite (always on empty unless I unplug it)and I have found a pinhole in the float. I will be replacing it one evening this week and will report back with the results. __________________ 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

11-29-2004, 08:01 PM	#5
Brainchild Still drivin' a Rat Rod Join Date: Sep 2004 Location: Monett Missouri Posts: 4,925	I have successfully taken the sender apart,and cleaned the contacts inside and it work.I did it on the 71 I am now driving. All I did was bend the little tabs out with a small screwdriver,enough to allow the square box,with the float arm through it to come off,and then clean the inside of the sender with some contact cleaner,and put it back together,and it works great.If it's just dirt could save ya some $$$.I mean ya gotta order one anyway Be careful not to break the tabs off,they are really small You can ground the unit,and plug the wire into the sender,and move the float arm to test it. __________________ Rusty Member #13872 Instead of saying.....you are a discomfort in the back of my front.....one should be able to say...... you are a pain in the a$# 71 GMC LWB 49 Chevy 85 Chevy G20 Check out my website

11-29-2004, 08:14 PM	#6
Robert1970C20rstbukt Registered User Join Date: Jun 2004 Location: Beeville, Texas Posts: 1,943	I did the same thing Branchild did, I just cleaned mine out. It had yellow-green corrosion all inside it so I sprayed some LPS industrial contact cleaner on it, put it back together and it worked like it should. __________________ RJD 1984 Chevrolet C30 welding truck 454/SM465 1977 GMC C15 pickup 350/TH350 1970 Chevrolet C20 pickup 350/TH400 1970 Chevrolet K20 Suburban 454/TH350 1969 GMC 8500 478M V6/5 spd winch truck

11-29-2004, 09:09 PM	#7
Blue Beard Registered User Join Date: Jan 2003 Location: Washington State Posts: 8,834	Don't mean to hi-jack a thread but this is along the same lines. Any help with a dual tank setup.....no matter which tank is switched on only reads 1/4 tank when full... __________________ 1970 Chev CST 2003 Harley Fatboy 1975 Chevrolet Step Van 1956 Chev Bel Air 1977 Blazer 2WD For Sale $3000.00 1978 Blazer 2WD For Sale $7000.00 1978 Silverado 2005 Monte Carlo

11-29-2004, 09:07 AM	#2
JimKshortstep4x4 Senior Member Join Date: Jul 2001 Location: Muskegon,MI,USA Posts: 6,026	Can you clarify on what happens when the gauge is hooked up or unhooked up? You said tha when it is hooked up it reads past full but unhooked it read empty. The gauge really should just do the opposite. Jim

11-29-2004, 07:46 PM	#4
SnS C10 Registered User Join Date: Jul 2004 Location: Lomita, Ca Posts: 1,225	actually i checked it out again and when i unhook the sending unit wire, the gauge reads past full. it does the same on my new vdo gas gauge. so i replaced the wire to see if the wire is bad. it did the exact same thing with a new wire. so im gonna be ordering a new sending unit, thanks guys



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