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Chevrolet Repair/Caprice -Fuel/Electrical Issue?

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Question
1994 Chevy Caprice Classic LS
4.3 V8

This problem has happened before but this time resulted in not starting for several days so i gave in and started troubleshooting.

No symptoms leading up to this issue.
Fuel gauge read past full but no start. (Before I could wait a day or even disconnect the ground from the battery and the car would start)
Sometimes the gauge would go normal but as soon as I cranked it over, back to full and not start. No hum from the pump.
Changed pump
changed filter
checked FPR
checked MAP

It drove up the road great, pulled back in and again, guage past full and it died. It didn't start right back up right away, but after a few minutes it did.
I figure its electrical but not sure where to start. Can anyone point me in the right direction or something.....anything......?

Answer
GOOD DAY RACHEL, WELL I WILL TRY MY BEST TO HELP YOU OUT HERE,FIRST THINGS FIRST..LETS NOT WORRY ABOUT WHAT THE FUEL GAUGE IS DOING..THIS MAY HAVE A BAD SENDING UNIT OR GAUGE FAULT..
LETS FIND OUT WHAT THIS ENG DOES NOT HAVE WHEN IT WILL NOT START AND THEN WE CAN ATTACK THAT.
WHAT YOU WILL NEED TO DO WHEN THIS WILL NOT START IS CK FOR FUEL OR SPARK AT THE PLUGS. HAVE SOMBODY CRANK THIS OVER WHILE YOU REMOVE A PLUG WIRE AND INSERT A SCREW DRIVER IN THE PLUG END AND HOLD THAT SCREW DRIVER ABOUT 1/4 INCH FROM A METAL OBJECT,, THERE SHOULD BE SPARK THERE ON OFF ON OFF. YOU COULD CK THIS WHEN THE ENG DOES RUN SO YOU WILL KNOW WHAT TO LOOK FOR WHEN IT WILL NOT START...DONT HOLD ON TO THE SCREW DRIVER WHILE IT IS CRANKING YOU MY GET SHOCKED.. WONT KILL YOU HOWEVER, WONT FEEL GOOD..SO IF THERE IS SPARK THERE AND CAR STILL WILL NOT RUN CK FOR FUEL. A EASY TEST IS GET YOURSELF A CAN OF STARTING FLUID AND SPRAY IT INTO THE INTAKE,IF IT RUNS LIKE THIS YOU KNOW YOU HAVE A FUEL PROBLEM.[JUST AS A TEST].SO BECAUSE YOU HAVE REPLACED THE FUEL PUMP YOU WILL NEED TO CK FOR POWER ON THE GREY WIRE GOING INTO TO FUEL PUMP [SENDING UNIT AT THE HARNESS,SHOULD HAVE 12 VOLTS WHILE THE ENG IS CRANKING OVER[WILL HAVE POWER AFTER TURNING THE KEY OFF AS WELL FOR 3 SECONDS] AND ALSO CK FOR GROUND [BLACK WIRE]I SUSPECT YOU WILL NOT HAVE POWER HERE.IF THIS IS THE CASE YOU HAVE A WIRING PROBLEM TO THE PUMP..CK AT THE FUSE BOX FOR THE PUMP RELAY. REMOVE IT AND JUMP THE POWER LEAD AND FUEL PUMP LEAD TOGETHER THIS WILL POWER UP THE PUMP LEAD..NOW TRACE THE WIRE TO THE PUMP AND YOU WILL MORE THEN LIKELY FIND A BREAK IN THE HARNESS SOMEWHERE..IF YOU JUMP IT AND NOW YOU HAVE POWER TO THE GREY WIRE AT THE PUMP HARNESS PLUG IN BACK YOU KNOW THAT WIRE IS GOOD..
SO IF THIS IS THE CASE YOU MAY HAVE PROBLEMS FROM THE IGN SWITCH TO THE FUEL PUMP RELAY NOT SUPPLYING POWER TO THE RELAY..THIS SHOULD KEEP YOU BUSY FOR A WHILE..LET ME KNOW WHAT YOU FIND AND GOOD LUCK TO YOU,,,TOM...

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TOM SHEETS

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PLEASE READ ALL OF THIS BEFORE ASKING ANY QUESTIONS. IF THIS CHEVY SECTION IS MAXED OUT.YOU CAN REACH ME IN THE OLDS/BUICK SECTION. Will answer questions from 6:00am to 10:00pm all days [EST][[[ NO DIESEL OR PAINT QUESTIONS]]] will answer all 1965 to present QUESTIONS ON ALL GM'S on mechanics of these cars. Keep in mind i am not there in person i am going on what you are telling me !! PLEASE IF ASKING A QUESTION GIVE ME AS MUCH INFO AS POSSIBLE. THE MORE THE BETTER. SUCH AS YEAR,MAKE,MODEL,ENGINE SIZE. THIS WILL HELP ME HELP YOU. I will not be able to answer all questions because of some situations that i would really need to be there and see things for myself,such as electrical issues. In many cases i would need wiring diagrams. I can also give you an estimate on what the cost would be at our repair shop as an idea to help you. Keep in mind that my answer is ONLY MY ADVICE,ck with your mechanic as well.. >> THANK YOU, TOM..

Experience

I have been a ASE certified master mechanic for over 30 years and certified IN ALL 8 CATEGORIES,[engine repair,engine performance,auto trans,manual trans,clutches,steering and suspension,brakes,electrical systems,heating and air/cond. I am also a state CERTIFIED inspector for over 30 years. I do computer work [pcm]fault codes,pcm flashing,state inspection monitor readiness,repairs on exhaust,fuel service,[injection and carburetor,] charging system problems, running issues,alignments,frame problems,tire balance,struts and of course standard and anti-lock brakes.

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nys state auto repair industry and ase group.

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high school,4 years of tech school,and many many hours of auto training with many gm classes and aftermarket training classes..

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ASE MASTER TECH CERTIFIED IN ALL 8 CATEGORIES.NYS INSP LICENSE AND A/C CERTIFIED

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