1969 Fuel Gauge Stuck? - Chevelle Tech
Electrical & Wiring Troubleshooting electrical problems.

 1Likes
  • 1 Post By Jim Streib
 
LinkBack Thread Tools Search this Thread Display Modes
post #1 of 5 (permalink) Old Oct 2nd, 17, 2:06 PM Thread Starter
Tech Team
 
Join Date: Apr 2017
Posts: 36
1969 Fuel Gauge Stuck?

I've read several threads on this, but sorry, can't seem to get my arms around this?
My gauge worked fine until the last couple weeks. Works fine from Full to a tick under half and tracks perfectly - then nothing my last 6-7 gallons?
Drogjr66 is offline  
Sponsored Links
Advertisement
 
post #2 of 5 (permalink) Old Oct 2nd, 17, 5:45 PM
Lifetime Premium Member
Eric
 
Join Date: May 2017
Location: Walden, NY
Posts: 629
Re: 1969 Fuel Gauge Stuck?

Likely your sender is worn out. It varies resistance as the float drops from 90 ohms at full down to zero at empty. You can pull the wires at the dash and measure the resistance to ground of the one going back to the tank. If it's not dropping lower than about 45 ohms, then that is why your needle remains at 1/2. If it is, it could be your guage. Mine did the same thing. There is a wiper on a coil of wire at the sender. That coil of wire had worn through. Drop your tank and have a look.
Dansk is offline  
post #3 of 5 (permalink) Old Oct 2nd, 17, 7:08 PM
Senior Tech Team
Eric
 
Join Date: Aug 2011
Location: Poteau, Ok
Posts: 4,109
Re: 1969 Fuel Gauge Stuck?

If you remove the wire to the sender with the key on, your gauge will drive past full. If you ground that same wire the gauge will go to empty. If both of these things happen then your sender is no good.

Your just jealous because you can't hear the voices!

1967 Olds Cutlass 468 BBC/T400
1963 Plymouth Fury 440/Torqueflite
2007 Ford Mustang GT (momma's car)
oldcutlass is offline  
 
post #4 of 5 (permalink) Old Oct 7th, 17, 10:03 PM
Senior Tech Team
 
Join Date: Oct 2003
Location: Saint Louis
Posts: 1,133
Re: 1969 Fuel Gauge Stuck?

To expand on what oldcutlass stated, this can give a false positive test. Granted the gauge with the ignition switch on and then grounding the sender wire in the trunk should make the gauge go to empty and then when ungrounded should have it going to full, you can also get the same results if the gauge has a defective shunt resistor on it.

Here are some tests I did on a 67 Impala gauge that is designed to work with a 0-90 ohm sender:









You can see how the gauge is thrown off without the shunt.

Ideally do some tests at the trunk connection to verify things before replacing the sender in the tank that might be good but instead you may have a gauge shunt issue.


Jim
454bbss likes this.

Always working on something:
To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts.

To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts.
Jim Streib is offline  
post #5 of 5 (permalink) Old Aug 13th, 18, 9:22 AM Thread Starter
Tech Team
 
Join Date: Apr 2017
Posts: 36
Re: 1969 Fuel Gauge Stuck?

Hi All;
Finally back to this issue. I've checked the gauge only from the connection in the trunk (grounded and ran to empty - removed wire ran to full, etc.) With that appearing to work correctly - I filled the tank and have been driving the gas out of it this week. Jostling the trunk around every time I returned home, I believe I loosened the sending unit in the tank to start working again. It's been tracking on it's way down from about 5/8.

Here's the weird thing. I ran the car out of gas the first week I had it - and gauge read 1/4 when it ran out. So when I got to gas station - I filled up - and the tank only took just over 12 gallons? It's a replacement tank. Can a 12 gallon tank exist? It's a new tank with a new sending unit.

This leads to another problem, I'm pretty sure I'm going to run out of gas in the next day or two right around 1/4 tank ( I have a gas can in trunk this time!). But all the OHM readings are spot on for where the gauge reads now (5/16 full gas - ohms are 29.0)

So if I run out the tank at 22.5 ohms, what's my options to get gauge closer to reality?

Thanks for your thoughts on this!
Attached Thumbnails
Click image for larger version

Name:	IMG_2413.jpg
Views:	22
Size:	67.3 KB
ID:	572522  
Drogjr66 is offline  
Sponsored Links
Advertisement
 
Reply

Quick Reply
Message:
Options

Register Now



In order to be able to post messages on the Chevelle Tech forums, you must first register.
Please enter your desired user name, your email address and other required details in the form below.

User Name:
Password
Please enter a password for your user account. Note that passwords are case-sensitive.

Password:


Confirm Password:
Email Address
Please enter a valid email address. Note, you will be sent a confirmation request to this address.

Email Address:
OR

Log-in









Old Thread Warning
This Thread is more than 376 days old. It is very likely that it does not need any further discussion and thus bumping it serves no purpose.
If you still feel it is necessary to make a new reply, you can still do so though.

Thread Tools Search this Thread
Show Printable Version Show Printable Version
Email this Page Email this Page
Search this Thread:

Advanced Search
Display Modes
Linear Mode Linear Mode



Posting Rules  
You may post new threads
You may 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
Trackbacks are On
Pingbacks are On
Refbacks are On

 
For the best viewing experience please update your browser to Google Chrome