The 1947 - Present Chevrolet & GMC Truck Message Board Network







Register or Log In To remove these advertisements.

Go Back   The 1947 - Present Chevrolet & GMC Truck Message Board Network > General Truck Forums > Electrical

Web 67-72chevytrucks.com


Reply
 
Thread Tools Display Modes
Old 07-14-2018, 01:03 PM   #1
dave`12
Registered User
 
dave`12's Avatar
 
Join Date: Sep 2015
Location: miami florida
Posts: 521
Fuel gauge issue

A while back I replaced the sender, and all was working well. Other day, the battery died. After jumping, the fuel gauge read 1/4 tank (it was over 3/4).

Shut it off, on the next restart, the gauge read empty and has stayed there.

I unhooked the wire to the sender, gauge went past full (way past).
Unhooked tan wire at fuse box, same thing.

Checked voltage at the box where the tan wire goes, 7.8. Test light lights, but dim. Is this supposed to be less than 12?

Ran a new wire from fuse box to sender, and the same thing happened, so I think that wire is ok.

All fuses seem ok (does anyone know which fuse controls this? I can't read anything on the old box.

So what is the next test?

thanx
dave`12 is offline   Reply With Quote
Old 07-14-2018, 02:44 PM   #2
dave`12
Registered User
 
dave`12's Avatar
 
Join Date: Sep 2015
Location: miami florida
Posts: 521
Re: Fuel gauge issue

Pulled the sender. If I move it up and down, the gauge moves.

Sender appears undamaged, float looks undamaged, not full of gas. I looks like it is installed correctly.

But when I put it back in the tank, the gauge still goes to empty.
dave`12 is offline   Reply With Quote
Old 07-14-2018, 03:00 PM   #3
dave`12
Registered User
 
dave`12's Avatar
 
Join Date: Sep 2015
Location: miami florida
Posts: 521
Re: Fuel gauge issue

Took sender out and grounded it. hooked up a wire from post to the sender wire, moved float, and it appeared to work correctly.

Put sender in bath full of water, float worked.

Cool bubbles came up. Shook float, heard liquid inside. Hmm, looks like a cracked float. I think I got my culprit.

Bummer.

Thanx for all the help. No, that's not sarcasm. This place is great, and all this happened in a few minutes, did not expect an answer that fast. But it was
kinda like bouncing stuff off of friends anyway

Last edited by dave`12; 07-14-2018 at 03:22 PM.
dave`12 is offline   Reply With Quote
Old 07-14-2018, 04:41 PM   #4
dave`12
Registered User
 
dave`12's Avatar
 
Join Date: Sep 2015
Location: miami florida
Posts: 521
Re: Fuel gauge issue

Anyone know where to find just the float? I can't seem to locate it.

thanx
__________________
1967 C-10 4-speed, 350v8
dave`12 is offline   Reply With Quote
Old 07-14-2018, 09:04 PM   #5
dmjlambert
Senior Member
 
dmjlambert's Avatar
 
Join Date: Apr 2016
Location: Cypress, TX
Posts: 1,101
Re: Fuel gauge issue

I don't want you stuck here just talking to yourself! I see in the LMC catalog they have the float. What is your float made of?
dmjlambert is offline   Reply With Quote
Old 07-15-2018, 09:23 AM   #6
oldgold70c10
Who's got steelies?
 
oldgold70c10's Avatar
 
Join Date: Feb 2006
Location: Morrison, Oklahoma
Posts: 1,003
Re: Fuel gauge issue

I went thru this when I first bought my truck in 2006.
I bought the float from LMC and installed it in the original sender. My gauge still read empty.
Ened up the LMC float woulf float when I tested in water, but sank in gas. LMC float was heavier than stock float.
I ended up finding and soldering the pinhole in the original float, and it has worked since.
__________________
1970 C10 with '67 small window cab, 68 front end, blue; 305/TH350, 3.08 limited slip rear end, manual brakes, power steering; & 4-wheel drums-My daily driver.
1975 Chevelle Malibu Classic Coupe 350/th350 mint green
1970 C20 Suburban 350/700R4 4.10 gearing green & white
1978 Big 10 Silverado 350/th350, working ac, 2 tone blue-My summer daily driver

How to add a trip odometer to your 67-72 stock speedometer

How to rebuild your Q-Jet

My Truck Page
My Youtube Channel
oldgold70c10 is offline   Reply With Quote
Old 07-15-2018, 03:36 PM   #7
dave`12
Registered User
 
dave`12's Avatar
 
Join Date: Sep 2015
Location: miami florida
Posts: 521
Re: Fuel gauge issue

Quote:
Originally Posted by dmjlambert View Post
I don't want you stuck here just talking to yourself! I see in the LMC catalog they have the float. What is your float made of?
I do that a lot It's brass.

I found this float and ordered it.

https://www.classicparts.com/1947-72...ctinfo/23-575/

6.00 = 10.00 shipping. Steep, but I could not find it locally and it' cheaper than the sender.

@oldgold. I hope I'm luckier than you. I had thought about repairing it, has a long very tiny crack and I thought I would change the weight and make it read incorrectly. If the new one does not work, that is what I will try next.
__________________
1967 C-10 4-speed, 350v8
dave`12 is offline   Reply With Quote
Old 07-15-2018, 04:07 PM   #8
dmjlambert
Senior Member
 
dmjlambert's Avatar
 
Join Date: Apr 2016
Location: Cypress, TX
Posts: 1,101
Re: Fuel gauge issue

I don't think soldering it would change the buoyancy of it significantly, even if you used a lot of solder. But getting a new high quality metal one is even better and that's not a bad price delivered. I'm going to bookmark that link in case I need one in the future.
dmjlambert is offline   Reply With Quote
Old 07-15-2018, 04:24 PM   #9
TBONE1964
Cluster King
 
TBONE1964's Avatar
 
Join Date: Nov 2012
Location: Junction City, OR
Posts: 4,731
Re: Fuel gauge issue

I have two questions.

Did the float still float even when you heard some gas sloshing in it? The float is not going to sink from 3/4 tank to 1/4 tank unless it is full of gas and then I think it would hit bottom.

Second, have you tested the resistor? Pull the resistor from the back of the fuel gauge and test it. It should read in the area of 85-90 ohms. If it is anything less, such as 25 ohms, your resistor is bad. It is one of the more common reasons why a fuel gauge will not go past 1/4 full regardless of full level.
__________________
Contact me on all of your gauge cluster needs. I specialize in restoration, repair and parts sales for 67-72 Chevy and GMC trucks. email me at tbonegarris@yahoo.com

Also see my facebook page, classic gauge and cluster.
TBONE1964 is offline   Reply With Quote
Old 07-15-2018, 05:50 PM   #10
dave`12
Registered User
 
dave`12's Avatar
 
Join Date: Sep 2015
Location: miami florida
Posts: 521
Re: Fuel gauge issue

Quote:
Originally Posted by TBONE1964 View Post
I have two questions.

Did the float still float even when you heard some gas sloshing in it? The float is not going to sink from 3/4 tank to 1/4 tank unless it is full of gas and then I think it would hit bottom.

Second, have you tested the resistor? Pull the resistor from the back of the fuel gauge and test it. It should read in the area of 85-90 ohms. If it is anything less, such as 25 ohms, your resistor is bad. It is one of the more common reasons why a fuel gauge will not go past 1/4 full regardless of full level.
The tank was reading empty. When I removed the float and moved it up and down, the gauge went from empty and back. The sender is only 6 months or so old, I think it progressively filled up enough to make it sink.

I had it sitting on a towel that go wet from gas when I unhooked the fuel line, so I'm hoping enough leaked out to make it float in the tub. The bubbles told me that it was filling with water, but very slowly.

So I won't know for sure until I get the new one. Hoping this fixes it.
__________________
1967 C-10 4-speed, 350v8
dave`12 is offline   Reply With Quote
Old 07-30-2018, 01:29 AM   #11
dave`12
Registered User
 
dave`12's Avatar
 
Join Date: Sep 2015
Location: miami florida
Posts: 521
Re: Fuel gauge issue

New one fixed it.

thanx for input.
__________________
1967 C-10 4-speed, 350v8
dave`12 is offline   Reply With Quote
Reply

Bookmarks

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump


All times are GMT -4. The time now is 06:06 AM.


Powered by vBulletin® Version 3.8.11
Copyright ©2000 - 2018, vBulletin Solutions Inc.
Copyright 1997-2013 67-72chevytrucks.com