Aftermarket fuel gauge issues - JeepForum.com
Search  
Sign Up   Today's Posts
User: Pass: Remember?
Advertise Here
Jeep Home Jeep Forum Jeep Classifieds Jeep Registry JeepSpace Jeep Reviews Jeep Gallery Jeep Clubs Jeep Groups Jeep Videos Jeep Events Jeep Articles
Go Back JeepForum.com > Models > Jeep CJ Forum > Aftermarket fuel gauge issues

The Original 3/8" Ruffstuff Diff Cover!3" BDS Suspension Lift Kit - Jeep JK 07-11Introducing MONSTALINER™ UV Permanent DIY Roll On Bed Line

Reply
Unread 07-25-2015, 05:35 AM   #1
Marshal
Registered User
1985 CJ7 
 
Join Date: Apr 2011
Location: Virginia Beach, VA
Posts: 237
Aftermarket fuel gauge issues

My original fuel gauge went out, so I got a new autometer to replace it. The new gauge pegs all the way passed full regardless of fuel level. I'm trying to figure out if something else out of whack, or if I have the gauge miss-matched.

The gauge is an Autometer 10-73. 10 empty, 73 full.

The sending unit is for an MTS 21 gallon tank (this worked with the original fuel gauge, so should not be related to the problem at hand).

The gauge is currently only using the original wire to the sending unit. I have checked this wire for a short to ground, and it reads open when disconnected from both the gauge and the bullet connector near the sending unit. When plugged in at the sending unit, it gives an ohm reading that roughly matches what the fuel level should be, i.e full reads 75, half tank reads 25-30-ish, and I never run it empty so no idea below that range. So this wire should be in tact.

The gauge has a direct fused and switched power feed from the battery as per manufacturer instructions. The power, ground, and sending lines are all connected to the proper pegs. I've checked this at least 10 times to make sure I'm not crazy.

The sending unit has a new ground feed. This is run to a brass bolt I installed in the back of the Jeep when I had the fuel tank down to swap it. This grounding peg is a dedicated ground with a wire feed straight to the negative battery post.

Has anyone else installed these? Should I change the power feed to the pulsing feed that the original fuel sending unit used? Could the fact that I used a dedicated ground, rather than a body ground, affect the fuel gauge's reading? Should I chalk this up to a manufacturing defect and resign myself to purchasing a new gauge? I've checked the sending unit post of the gauge to see if it had an internal short, but that checked out ok. I'm not sure where else to look at this point.

Marshal is offline   Reply With Quote Quick reply to this message
Unread 07-25-2015, 06:02 AM   #2
John Strenk
Moderator
 
John Strenk's Avatar
1976 CJ5 
 
Join Date: Feb 2005
Location: Shalersville Ohio
Posts: 14,069
The original fuel gauge in CJ's (in the speedo) were 10 Ohms Full- 73 Ohms Empty...
Just the opposite of your gauge....

That being said, your gauge should act in reverse, not stay pegged.

I would check with a test light that your ground really is at ground potential.
Use a test light hooked to Battery (+) and touch it to your ground post on the gauge to be sure it lights up.

If your wiring is correct, then your new gauge is bad.
John Strenk is online now   Reply With Quote Quick reply to this message
Unread 07-25-2015, 06:43 AM   #3
bob4703
Registered User
1974 CJ5 
 
Join Date: Feb 2015
Location: Easley, SC
Posts: 152
If the sending unit worked with the original guage and the original guage no longer works and the replacement guage won't work either could the problem be the sending unit?

I share your frustration. Last year my speedometer went balistic and made so much noise I pulled over and disconnected the cable. Then the turning cable wiped out the fuel and temp guages. New cluster restored speedometer and fuel, but not the temp guage. Assumed bad wire and rewired--no luck. Replaced temp sending unit--no luck. F___ it! Got aftermarket guage (that I can see better) and installed it. Had to install sending unit that came with guage to get it to work. Won't even discuss the oil pressure meter which pegs when I turn on the heater fan! Next winter's project is rewiring the whole Jeep. There is a right way, a wrong way, and the Jeep way to make repairs!

Good luck!
__________________
-----

If it has rollup windows and A/C it ain't a Jeep. It is a rebranded Dodge!
bob4703 is offline   Reply With Quote Quick reply to this message
Unread 07-25-2015, 09:55 AM   #4
Marshal
Registered User
1985 CJ7 
 
Join Date: Apr 2011
Location: Virginia Beach, VA
Posts: 237
I may have reversed those figures, it's been over a month since I had time to look at it. Working out of town has a funny way of stalling projects lol. I'm heading over to mess with it now. I have my DVOM on me, hopefully the test light is in the CJ.

I feel you on the speedo gauge man. Mine wiped itself out a week before I got my new job. My temporary solution was to download a phone app called Digihud.
Marshal is offline   Reply With Quote Quick reply to this message
Unread 08-12-2015, 09:29 AM   #5
hbar
Member
1979 CJ7 
 
Join Date: Dec 2014
Location: Prosper, TX
Posts: 312
Do we know why/how it went out initially?

I love longshots.......IF it was initially a float problem, it would just read empty all the time. A new gauge would not address that, but would still read empty all the time. Unless...the new gauge were actually as the OP has stated: 10 empty & 73 full (reversed from OEM), the float would still be on the bottom of the tank and the gauge would read full regardless of the level. A quick search doesn't turn up any Autometer fuel gauges with 73 Ohm full, but another common fuel gauge setup is a 0 Ohm empty/90 Ohm full....which might look like a pegged FULL fuel gauge with a 10/73 sender that has its float on the bottom of the tank.

Just a thought, using the facts as presented. Can you share the Autometer model #?
hbar is online now   Reply With Quote Quick reply to this message
Unread 08-13-2015, 07:16 AM   #6
Marshal
Registered User
1985 CJ7 
 
Join Date: Apr 2011
Location: Virginia Beach, VA
Posts: 237
Mild dyslexia, it reads 10-12 full.I checked with a voltmeter. I tend to get things backward from time to time lol. But yeah, it's got to be a case of dead gauge from the factory. Everything else checks out no matter how many times i look or what angle I look from.
Marshal is offline   Reply With Quote Quick reply to this message
Unread 08-13-2015, 09:03 AM   #7
hbar
Member
1979 CJ7 
 
Join Date: Dec 2014
Location: Prosper, TX
Posts: 312
I'm not convinced you have a dead gauge yet, especially if the needle moves. Please share the AutoMeter model #.
hbar is online now   Reply With Quote Quick reply to this message
Unread 08-13-2015, 10:51 AM   #8
AFRd_CJ5
Registered User
1976 CJ5 
 
Join Date: Jan 2011
Location: Carson City, Michigan
Posts: 821
I'd have to look up the model # of mine, but I use an Autometer Ultra Lite fuel gauge that was for a Ford setup.
__________________
'76 CJ5
434 pump gas SBC with an NX/HVH plate system
th350/Coan 5,000 converter/Dana 300 tcase
Dana 30 front with 4.56's/Dana 44 rear with 4.88's
AFRd_CJ5 is offline   Reply With Quote Quick reply to this message
Unread 08-13-2015, 02:35 PM   #9
Marshal
Registered User
1985 CJ7 
 
Join Date: Apr 2011
Location: Virginia Beach, VA
Posts: 237
Autometer 3315. Ford/Chrysler fuel gauge. 73 ohms empty, 10 full.
Marshal is offline   Reply With Quote Quick reply to this message
Unread 08-13-2015, 03:03 PM   #10
hbar
Member
1979 CJ7 
 
Join Date: Dec 2014
Location: Prosper, TX
Posts: 312
Dang. I was really hoping it was the 0/90 style gauge.

I would say take the sender out and test it directly against the gauge. We never established the initial problem (at least we didn't in this thread afaik), so it's worthwhile to start eliminating variables and actually put hands/eyes/voltmeter on the subsystem; actually manipulate the sender to see the effect on the gauge. But that's just me. I'm lo-fi.
hbar is online now   Reply With Quote Quick reply to this message
Unread 08-13-2015, 07:07 PM   #11
Marshal
Registered User
1985 CJ7 
 
Join Date: Apr 2011
Location: Virginia Beach, VA
Posts: 237
Been there and done that. The sender is new, and last I checked (after old gauge quit, and before breaking down and installing new gauge) it worked like it was supposed to. As far as I can tell based on the ohm readings I'm getting between fill ups, the sender is still in working order.

The one thing that does have me a little leery is every gauge on the dash seems to be having trouble of some sort. The voltmeter is reading 12 volts, but the alternator is charging at 14. The factory fuel gauge is shot. The factory temp has a mind f it's own. And I'm not entirely sure I trust the pressure gauge at this point either.

Part of me is starting to wonder if the dash doesn't have a small amount of current running through it at this point. I installed a dedicated ground to the dash panel a while back, and last I checked that ground was still good. But if there was just a little current leaking in from somewhere who knows what kind of havoc it could wreak.
Marshal is offline   Reply With Quote Quick reply to this message
Unread 08-19-2015, 06:49 PM   #12
Marshal
Registered User
1985 CJ7 
 
Join Date: Apr 2011
Location: Virginia Beach, VA
Posts: 237
Got it! New Guage came in today, and it behaved the same as the one I had previously installed. So I went back to checking wore feeds.

Connected the dvom to the power feed and dedicated ground I ran specifically for the new fuel meter. Had 12 volts and assumed that meant both wires were good. That is where I was making my mistake. So I checked resistance from the sender wire and the group feed, It returned 60 ohms. Filled up this morning and maybe drove 8 miles, so I knew something was off. Changed grounds and the reading was 12 ohms - the proper reading for the full tank I had.

In short, the brand new ground wire had resistance somewhere and was probaby split in the casing. Go figure.
Marshal is offline   Reply With Quote Quick reply to this message
Unread 08-20-2015, 09:55 AM   #13
hbar
Member
1979 CJ7 
 
Join Date: Dec 2014
Location: Prosper, TX
Posts: 312
I'm curious to know what it did (if anything) to help your other gauge issues.

I was stupidly confident it wasn't the brand new gauge, especially an AutoMeter. There are no shortage of 100% legit stories here of people having all sorts of issues with brand new or re-man'd parts. However, I have never even once experienced this, so I remain skeptical (as is my nature) of new parts being the issue. Especially given that so many other things could be the culprit. Now that I've said this, I'm sure my next 10 new parts will all be faulty out of the box. Glad you got it worked out, and that it wasn't anything more sinister.
hbar is online now   Reply With Quote Quick reply to this message
Reply

Quick Reply
Message:
Options

Register Now

In order to be able to post messages on the JeepForum.com 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 e-mail address for yourself.
Note: All free e-mails have been banned due to mis-use. (Yahoo, Gmail, Hotmail, etc.)
Don't have a non-free e-mail address? Click here for a solution: Manual Account Creation
Email Address:

Log-in

Human Verification

In order to verify that you are a human and not a spam bot, please enter the answer into the following box below based on the instructions contained in the graphic.


Thread Tools






Jeep, Wrangler, Cherokee, Grand Cherokee, and other models are copyrighted and trademarked to Jeep/Chrysler Corporation. JeepForum.com is not in any way associated with Jeep or the Chrysler Corp.