Gas gauge is showing empty when full

Tiny
JBBRADY1
  • MEMBER
  • 1980 JEEP CJ7
  • 100,000 MILES
New fuel tank sending unit and new dash gauge, wiring checked out good, gas gauge stays on empty with full tank of fuel, what do I do
Thursday, December 15th, 2011 AT 3:07 AM

15 Replies

Tiny
CJ MEDEVAC
  • MECHANIC
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LETS GO BACK TO THE TANK

FIND THE SENDING UNIT WIRE AND DISCONNECT IT

NOT THE TANK END--BUT THE OTHER END HEADED FORWARD

GROUND THAT PUPPY--EVEN IF YOU HAVE TO RUN A JUMPER WIRE ALL THE WAY BACK TO THE NEGATIVE BATTERY POST

GAUGE SHOULD PEG OUT FULL

DISCONNECT AND LET ME KNOW YOUR RESULTS

I MAY CAN ASSIST YOU W/ THIS AND ANY OTHER CJ ISSUE

THE MEDIC
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Thursday, December 15th, 2011 AT 3:23 AM
Tiny
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IS TEMP GAUGE WORKING?

DID YOU REPLACE THE CLUSTER OR THE GAUGE WITHIN?

HOW DO YOU KNOW THE WIRING IS CORRECT. MARKED IT. DIAGRAM. ETC?

NOT TRYIN' TO BE A SMART ALEC, JUST WANT TO HELP W/ ALL AVAILABLE INFO FROM YOUR END

I GOT GOOD INFO, KEEP DISHING IT TO ME!

THE MEDIC
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Thursday, December 15th, 2011 AT 3:32 AM
Tiny
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WHAT YOU GOT FIGGURED OUT?

I THE CVR WENT OUT IN MY FUEL GAUGE YESTERDAY

THE COOL THING IS I DROVE IT DRY, AND STARTED SPUTTERING AT THE TOP OF THE HILL ABOVE MY SUBDIVISION. SORTA COASTED RIGHT INTO THE GAS STATION

1ST TIME IT'S BEEN COMPLETELY EMPTY SINCE I INSTALLED MY 21 GALLON POLYETHYLENE TANK.I JUST FOUND OUT IT WILL HOLD 22.060 GALLONS OF FUEL

SO I JUST ORDERED A FUEL AND TEMP GAUGE--(EBAY WAS THE BEST PRICES)

I WILL ALSO SLING OUT A COUPLE OF VIDEOS ON HOW TO TEST THE GAUGES W/ A TEST LIGHT AND VOLTMETER, WHEN YOU RESPOND (IF NEEDED)

I MOST LIKELY WILL TAKE PICS ALONG THE WAY OF REPLACING MINE

LET ME KNOW YOUR SITUATION

THE MEDIC
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Sunday, December 18th, 2011 AT 7:29 PM
Tiny
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AND WE GOT HIM ALL FIGURED OUT?

MY NEW FUEL AND TEMP GAUGES SHOULD BE HERE TODAY

I THINK BOTH WERE RIGHT AT $36

STILL WANT TO HELP IF YOU NEED ME

THE MEDIC
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Friday, December 23rd, 2011 AT 2:55 PM
Tiny
JBBRADY1
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Since the last time I talked w/u, have done a full off frame restoration, did a yj conversion to cj. Checked fuel tank sending unit with voltometer, replaced sending unit (new) when reassembling grounded tank to body, grounded body to frame back by the fuel tank, grounded battery to firewall, grounded firewall to frame, what's the best way to check the fuel gauge & temperature gauge in the dash cluster?

Also, put udi distributor in it to get the tach working, have 2 red wires coming out of the back of the tach, one has white tracer - is the one with white tracer the one to hook to distributor for the tach?

Get rid of your carter carb and put a webber on it. Car problems all solved when I did that.
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Tuesday, July 24th, 2012 AT 3:19 AM
Tiny
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HAD NO LUCK WITH THE WEBER AFTER A YEAR OF PLAYING W/ THE JETTING

I WENT W/A 390 4BBL HOLLEY AND AN OFFENHAUSER 4BBL INTAKE---USING AN O2 SENSOR AND AN ON DASH AIR/FUEL RATIO GAUGE TO JET IT CORRECTLY.....18 MPG HWY LAST TIME I CHECKED!

THE O2 AND METER MAY HAVE HELP ME W/ THE WEBER....WATER UNDER THE BRIDGE!

I CAN SHOW YOU MORE ON THE O2 METHOD IF YOU LIKE

YOU NEED TO GO BATTERY NEGATIVE "BIG CABLE" TO THE ENGINE 1ST----USING A GROUND STRAP OR BIG CABLE GO FROM ENGINE....AROUND MOTOR MOUNT...TO THE FRAME. YOU CAN GROUND THE BODY RIGHT OFF OF THE BATTERY

YOU NEED IT FROM BATTERY TO ENGINE 1ST, BECAUSE THE STARTER DRAWS SO MANY AMPS.....IT HAVING TO TRAVEL SO FAR OR IF YOUR OTHER GROUND GOT LOOSETHE STARTER WOULD ATTEMPT TO DRAW THRU YOUR SMALLER WIRES (THE MOST DIRECT ROUTE TO THE BATTERY).......FIRE!!!! NO MORE WIRE HARNESS!!!!YOU CRY LIKE A BABY!

IF SOMETHING GOT LOOSE ON THE BATTERY NEGATIVE TO ENGINE WIRE....THE STARTER WOULD NOT WORK....IT WOULD NOT BE ABLE TO "SEEK OUT" ANOTHER "SUBSTANDARD GROUND"........YOU WOULD STILL HAVE A JEEP!

TACH WORKS OFF ORF NEG WIRE TO COIL----I'M GUESSING THE SOLID COLOR WIRE IS THE SENDER WIRE.....GIMME THE MODEL AND MFGer, I'LL SEE IF I CAN LOOK UP THE DIAGRAM FOR IT

I HAVE INFO --- GOOD INFO ON THE GAUGE CLUSTER! ---ELABORATE ON WHAT YOU WANNA KNOW ABOUT THEM....DO THEY WORK?....NOT WORK?....NEED WIRE DIAGRAM? ETC?

I HAVE OTHER GOOD INFO TOO.....YOU WILL BE HAPPY WHEN YOU SEE WHAT I FOUND NOT TOO LONG AGO

I'M GUESSING YOUR EXHAUST MANIFOLD STILL HAS THE O2 PORT (NOW UNUSED)---YOU CAN USE IT FOR A GAUGE NOW!

http://www.bob2000.com/carb.htm

HIS TUNING PROCEDURES FOR THE WHOLE CARB ARE EXCELLENT!

GLAD TO HEAR YOU ARE REALLY HOOKED NOW!

YOUR TURN

THE MEDIC
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Tuesday, July 24th, 2012 AT 4:19 AM
Tiny
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I NEED TO KNOW WHAT KINDA STUFF YOU DID WITH THE CLUSTER BEFORE YOU PUT IT IN THE DASH. DID YOU "POWER IT UP" PRIOR TO INSTALLING IT?

THE MEDIC
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Tuesday, July 24th, 2012 AT 4:22 AM
Tiny
JBBRADY1
  • MEMBER
  • 7 POSTS
Yes, powered up on bench. I'm not running stock exhaust, running headers, aluminum intake off late model 258 (one that water runs thru it)no smog whatsoever on jeep. Brainbox on fender no longer in use. All manual gauges. Have manual temp gauge but would like to have dash gauge working too, especially fuel gauge, is it possible to put a site gauge in it. HOOKED BAD MANY YEARS. Jeep stays in garage - new toyota tundra sits outside!@!Lol
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Tuesday, July 24th, 2012 AT 3:46 PM
Tiny
JBBRADY1
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Ps note:my wife loves doing this. NO 02 sensors. Check into wiring on tach a lil closer if u can, appreciate it. Original wiring had a green wire off coil said tach on it. It went to brainbox.
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Tuesday, July 24th, 2012 AT 3:48 PM
Tiny
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YOU PROBABLY FRIED THE "CVR" IF YOUR GROUND WAS NOT GREAT

http://home.roadrunner.com/ john.strenk/Gauge%20web%20page/CJSpeedometerGaugeQuickTest.htm

http://home.roadrunner.com/ john.strenk/Gauge%20web%20page/basic_troubleshooting_for_cj_gau.htm

LOOK THIS OVER

IF YOU NEED GAUGES.....LOOK AT THESE!

http://www.oconeeoffroad.com/servlet/the-43147/Fuel-and-Temperature-Gauge/Detail

KEEP ME POSTED ON WHAT YOU FIND OR HAVE A QUESTION---I DO HAVE MORE INFO I CAN GIVE YOU

I'M ATTEMPTING TO AID 4 CJs NOW, ON HERE.....I GET CARRIED AWAY WITH MY LOVE FOR GETTING THEM GOING.....I HAVE TERRIBLE "CRS", SO BEAR WITH ME IF I CONFUSE ONE WITH ANOTHER!

THE MEDIC

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Tuesday, July 24th, 2012 AT 6:38 PM
Tiny
JBBRADY1
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WHAT DO U MEAN BY "cvr" oN TACH, THE 2 RED WIRES COMING IN THE BACK OF IT, THE SOLID RED IS BATTERY WIRE, THE ONE WITH TRACER IS COIL WIRE. HOOKED THE TRACER WIRE TO THE DISTRIBUTOR ON THE TACH LUG, WHEN HOOKED UP, TACH WORK BUT KILLED ENGINE. REMEMBER I AM RUNNING A CHEVY STYLE DISTRIBUTOR WITH COIL MADE ON TOP OF DISTRIBUTOR CAP. IS THE AMC TACH COMPATIBLE WITH THAT DISRIBUTOR? HOW DOES THE TACH GROUND, THER IS NO GROUND WIRE ON THE BACK EXCEPT FOR THE LIGHT.
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Wednesday, July 25th, 2012 AT 2:34 AM
Tiny
CJ MEDEVAC
  • MECHANIC
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CONSTANT VOLTAGE REGULATOR (CVR) THIS IS IN YOUR FUEL GAUGE IT PROVIDES ABOUT 5 VOLTS TO THE FUEL GAUGE---THEN JUMPERS OVER TO THE TEMPERATURE GAUGE TO POWER IT. THERE'S SORTA NO OTHER "REASONABLE WAY" TO POWER THE FACTORY GAUGES. THAT I HAVE FOUND

THIS THING IS NOT A "TRANSFORMER" IT ACTUALLY WORKS LIKE A VOLTAGE REGULATOR ON 1930s--EARLY 1970s ALTERNATORS. IT CONSTANTLY GETS "TOO MUCH VOLTAGE". TURNS OFF. GETS "TOO LITTLE VOLTAGE". TURNS ON. FOREVER AND EVER!

THE LINKS I SENT ABOVE SHOULD EXPLAIN CVR

I WROTE YOU A NOVEL EARLIER AND IT GOT LOST WHEN I SUBMITTED, SO I CRANKED OUT A QUICK ONE TO GIVE YOU SOMETHING!

I AM GOING TO SUBMIT THIS NOW, THEN SEE WHAT I CAN FIND OUT ABOUT INSTALLING YOUR TACH ONTO YOUR AFTERMARKET DISTRIBUTOR

I'LL TRY TO POST TOMORROW AFTER WORK

SEE YOU THEN

THE MEDIC
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Wednesday, July 25th, 2012 AT 3:19 AM
Tiny
CJ MEDEVAC
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FOUND THESE IN A HURRY....ALMOST 24:00 MUST WORK IN MORNING!

THESE ARE SORTA CRAPPY AS FAR AS THE CAMERA

http://www.youtube.com/watch?v=hQVoGx0UETI

THIS ONE TOO

http://www.youtube.com/watch?v=guRwqxKrdWM

I DID NOT SEARCH FOR MORE

I'M WORKING AT ADVANCE AUTO PART TIME

I'LL SEE IF I CAN SNAP SOME PICS THAT MIGHT HELP

LET ME KNOW IF THESE VIDEOS OFFER ANY GOOD INFO, I SKIMMED THRU THEM

THE MEDIC
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Wednesday, July 25th, 2012 AT 3:35 AM
Tiny
JBBRADY1
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  • 7 POSTS
FUEL GAUGE WAS BAD, WORKING ON TACH NOW THANKS FOR INFO
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Friday, July 27th, 2012 AT 8:24 PM
Tiny
JBBRADY1
  • MEMBER
  • 7 POSTS
HOW CAN I MAKE A STOCK TACH WORK WITH A UDI DISTRIBUTOR
(SAME AS CHEVY DIST WITH COIL PACK MADE ON TOP OF DISTRIBUTOR
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Friday, July 27th, 2012 AT 8:29 PM

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