Fuel Gauge INOP STILL!!!!! Even after new sending unit and fuel tank.

Rustymopar · Jun 5, 2013

Fuel Gauge INOP STILL!!!!! Even after new sending unit and fuel tank.
I traced the wire from the trunk to under that channel on the inside of the rocker.
I did see where a wire was pinched by the sill plate so I cut it out and spiced it
when I had the old tank in. That didn't resolve it. So I dropped that miserable tank while
laying on my back to change the sending unit and decided to just replace the entire tank.
It had some rusty spots.
So now I have a new tank and sending unit and the SOG still isn't working.

Any Idears?

PS - does the fuel gauge wire run outside of the rear light bundle towards the dash?

Thanks
R

5wndwcpe · Jun 5, 2013

Stupid question - but the sending unit is grounded, yes ?

Meep-Meep · Jun 5, 2013

I'm pretty sure the fuel gauge wire comes out of the rear harness and runs along the trunk floor then pokes through a grommet. If you ground the fuel gauge wire the gauge should rapidly go to the full reading (don't leave it grounded longer than it takes to see movement). If the gauge doesn't move then it's possible the voltage limiter in the dash is bad.

X2 on grounding the fuel gauge sender.

benno440 · Jun 5, 2013

did you put the ground strap on? one end goes on the sending unit outlet tube and the other end goes onto the metal part of your fuel line, another trick i used for better grounding was soldered a wire onto this strap and then crimped a termial on other end and put it to a bolt on the body, power wire goes from little stud on sending unit up through trunk grommet along rocker to under the dash.

like meep said maybe voltage limiter or a faulty gauge or connection, if you have the ground correct and power wire correct then its under the dash most likely.

i have heard many stories that the factry fuel gauge never really works properly.
good luck, know any auto sparkies?

Dennis H · Jun 6, 2013

Mine used to read full with the factory tank etc. replaced the tank, sending unit. Now reads just over half when full. That's it. Can't fix it. Done. Ground/schmound. P

hunt2elk · Jun 6, 2013

Meep-Meep said:
I'm pretty sure the fuel gauge wire comes out of the rear harness and runs along the trunk floor then pokes through a grommet. If you ground the fuel gauge wire the gauge should rapidly go to the full reading (don't leave it grounded longer than it takes to see movement). If the gauge doesn't move then it's possible the voltage limiter in the dash is bad.

X2 on grounding the fuel gauge sender.

Meeps is right, this is the easiest way to check everything forward of the tank. Does the temp. gauge work?

bigmanjbmopar · Jun 6, 2013

Dennis H said:
Mine used to read full with the factory tank etc. replaced the tank, sending unit. Now reads just over half when full. That's it. Can't fix it. Done. Ground/schmound. P

You did know the actual gauge itself is adjustable right? I know this is a pain in the *** put if you can get your cluster out and the gauge out look behind it there are two very small half round holes on either side of the gauge where there are for lack of a better word cogs, these are used to adjust the needle up or down you can literally take the needle past empty or full with this adjustment.

Meep-Meep · Jun 6, 2013

Dennis H said:
Mine used to read full with the factory tank etc. replaced the tank, sending unit. Now reads just over half when full. That's it. Can't fix it. Done. Ground/schmound. P

I think some calibration is in order.

wannadrag · Jun 8, 2013

Meep-Meep said:
I think some calibration is in order.

The Chinese sending units are crap,mines new and reads the same 1/2 full when the tank is full.From what I have read the ones Dixie Mopar Parts sells are the best,made by the same company that supplied Chrysler when these cars were new.

Rustymopar · Jun 9, 2013

I did reinstall the grounding strap. But will check to make sure its a good ground. I'm also going to pull that wire out from beneath the sill plate and ground it. That should move the gauge to full - correct? The gauge does moves about 1/16" to just below E when I turn the key to run. Not feeling today though.. I had a 50th Bday party for my Fiancé last night.

PUNKN8R · Jun 9, 2013

Does your temp gauge work ?? Sending unit in tank getting power? should receive a 5volt pulse from voltage limiter on rear of dash panel it could be possible if wire was pinched and grounded out it may have fried the voltage limiter and the reason I ask if temp gauge works both the fuel sender and the temp gauge get a 5v pulsating power source from the voltage limiter.

dodge41969 · Jun 9, 2013

You don't need to drop the tank to change the sender....just jack up the body so the rear end/shocks are extended, (I know, too late). Now assuming the temp gauge works that rules out the voltage limiter's gone bad, (then neither gauge would work), I would get under the dash and try and tighten the fuel gauge studs, (3/8 nuts)...it doesn't take much for them to lose contact on the circuit board) I've had quite a few act like the gauge was bad, and all it was was a lose connection at the circuit board.
If you have a question regarding gauges you can PM me. I used to work for Redline Gauge Works, I currently work at North Hollywood Speedometer.

Rustymopar said:
Fuel Gauge INOP STILL!!!!! Even after new sending unit and fuel tank.
I traced the wire from the trunk to under that channel on the inside of the rocker.
I did see where a wire was pinched by the sill plate so I cut it out and spiced it
when I had the old tank in. That didn't resolve it. So I dropped that miserable tank while
laying on my back to change the sending unit and decided to just replace the entire tank.
It had some rusty spots.
So now I have a new tank and sending unit and the SOG still isn't working.

Any Idears?

PS - does the fuel gauge wire run outside of the rear light bundle towards the dash?

Thanks
R

Dennis H · Jun 9, 2013

Tried everything. Can't fix the goddam thing. It is a PIA. Many better than me can't get the thing to read full. And, most are better.

440+6 · Jun 10, 2013

I've tried all of the above and my fuel and temp still read low (about 1/4 to 3/8 of the gauge less than they should).
I gave up on trying to fix this and kinda learned to live with it but I sure would love to hear a solution.

PUNKN8R · Jun 10, 2013

Did you try taking a wire stripped on both ends reach under dash locate voltage regulator, ground one end of wire to bare metal and touch the voltage regulator body with the other end thus giving it an optional ground ( I found in my case that it was a grounding issue in the circuit board so I took a 12 gauge wire and soldered to the voltage regulator and grounded it to under side of dashboard, this solved my problem.) Good Luck Man !!!

Rustymopar · Jun 10, 2013

Its a rainy day. I'm going to try and tackle it today.. I will check the strap first... nuts on the fuel gauge.
Does anyone have a picture and location of a voltage limiter?

440+6 · Jun 10, 2013

This is a 69 cluster, the limiter is circled, it just pulls out to remove.

1969 Mopar B-Body Instrument Cluster 2.JPG

Rustymopar · Jun 10, 2013

Or is it the same component called a voltage regulator beneath the hood on the firewall?

- - - Updated - - -

440+6 said:
This is a 69 cluster, the limiter is circled, it just pulls out to remove.

View attachment 121499

Thanks... I will try the couple easier things first,,

1) Ground the wire from sending unit to gauge and see if it moves the needle.
2) Check gorunding strap for good ground from sending unit to fuel line.
3) Check the nuts on the back of the fuel gauge.
4) R and R voltage limiter.

Sound about right?

440+6 · Jun 10, 2013

And as punkn8r stated a wire from a known good ground to the back of the voltage limiter on the back of the cluster.
Let us know if anything works.

Rustymopar · Jun 10, 2013

Rustymopar said:
Or is it the same component called a voltage regulator beneath the hood on the firewall?

- - - Updated - - -

Thanks... I will try the couple easier things first,,

1) Ground the wire from sending unit to gauge and see if it moves the needle.
2) Check gorunding strap for good ground from sending unit to fuel line.
3) Check the nuts on the back of the fuel gauge.
4) R and R voltage limiter.

Sound about right?

I tried all 4. Nothing. I pulled a voltage limiter from a parts car and tried it as well.

I did get the gauge to go to full... I took a jumper wire and went from the blue wire which comes from the fuel sending unit and leads into a bundle plug end behind the kick panel. I stuck my jumper into the gauge side of the plug bundle and grounded it. It went all the way past full.

The needle does move just a wee little bit to just below E when I turn the key on.

Grrrrr.. tired of laying on my back...

Whats next?.. I know the gauge works and the voltage limiter seems to be working..

- - - Updated - - -

PUNKN8R said:
Did you try taking a wire stripped on both ends reach under dash locate voltage regulator, ground one end of wire to bare metal and touch the voltage regulator body with the other end thus giving it an optional ground ( I found in my case that it was a grounding issue in the circuit board so I took a 12 gauge wire and soldered to the voltage regulator and grounded it to under side of dashboard, this solved my problem.) Good Luck Man !!!

Headed out to try this.. I will touch it first and ask the Mrs. to check the gauge as I do it before I go soldering.

- - - Updated - - -

dodge41969 said:
You don't need to drop the tank to change the sender....just jack up the body so the rear end/shocks are extended, (I know, too late). Now assuming the temp gauge works that rules out the voltage limiter's gone bad, (then neither gauge would work), I would get under the dash and try and tighten the fuel gauge studs, (3/8 nuts)...it doesn't take much for them to lose contact on the circuit board) I've had quite a few act like the gauge was bad, and all it was was a lose connection at the circuit board.
If you have a question regarding gauges you can email me at: [email protected] I used to work for Redline Gauge Works, I currently work at North Hollywood Speedometer.

I did this... still nada... I'm going to try and ground the voltage limiter to see if that's it.. Just waiting on another set of eyes.

Fuel Gauge INOP STILL!!!!! Even after new sending unit and fuel tank.

Well-Known Member

Huge Member

дворянин

Well-Known Member

FBBO Gold Member

FBBO Gold Member

Newb with a view

дворянин

Well-Known Member

Well-Known Member

Well-Known Member

Well-Known Member

FBBO Gold Member

FBBO Gold Member

Well-Known Member

Well-Known Member

FBBO Gold Member

Well-Known Member

FBBO Gold Member

Well-Known Member

Similar threads