Voltage drops to nothing when I turn the key

Tiny
MXROK
  • MEMBER
  • 1986 JEEP CJ7
  • 177,000 MILES
86 cj7 258 auto tilt wheel; turn key to start volt drops but nothing, no click no nothing. Replaced solenoid, switch on column, nothing. Will start if I jump across solenoid maybe park/neutral safty sw crapped
Wednesday, October 26th, 2011 AT 10:16 PM

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Tiny
HMAC300
  • MECHANIC
  • 48,601 POSTS
Check the battery first and clean the terminals. If you don't have at least 12.4 volts on a digital vom then charge it then check yoru charging system. Check yoru starter relay.
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Wednesday, October 26th, 2011 AT 10:49 PM
Tiny
CJ MEDEVAC
  • MECHANIC
  • 11,005 POSTS
HAVE YOU BEEN HAVING NO PROBLEMS WITH IT. SOMETHING THAT JUST STARTED?

IMMA CJ GUY MYSELF, I TRY TO AID ALL OF THE CJs COMING THRU (SOLE REASON I EVEN STARTED ANSWERING AT 2CARFELLERS), I WILL HELP TO THE BEST OF MY ABILITY, I HAVE MANY PICS OF MINE AND OTHERS, THAT MAY HELP. I WILL HELP YOU WITH THIS, AND WILL TRY TO HELP YOU WITH ANY OTHER ISSUE, BIG OR SMALL----KEEP ON ASKING RIGHT HERE AT THIS POST.I HAVE ONE NOW (CJ) WITH 94 RESPONSES.I WAS TOLD, THE "THREADS" ARE ALMOST INFINITE HERE.

TRY THIS, WHAT DOES APPLY TO YOUR RIG!

Xnostart

THIS IS SORTA GENERIC. AS I HAVE USED IT WITH OTHER VEHICLES TOO.

YOU COULD HAVE FAULTY RELAYS OR FUSES. SAVE RELAYS FOR LAST! (IF ANY)

CHECK YOUR FUSES!---YOUR OWNERS MANUAL MAY SHOW YOU LOCATIONS THAT YOU KNEW NOTHING ABOUT!

REMOVE AND REPLACE "SUSPECT" FUSES SEVERAL TIMES--THIS MAY SCRAPE OFF CORROSION AND GIVE THEM BETTER CONTACT!

THIS WILL WORK FOR YOU, PROVIDED THAT YOUR BATTERY IS GOOD---OR YOU CAN BE JUMPED OFF!

REMEMBER "NEW STUFF" CAN BE BAD TOO!

YOUR STARTER MAY BE BAD!

YOUR SOLENOID MAY BE BAD!

Try the stuff below (actions),

IN MOST CASES THIS IS THE PROBLEM!

PEOPLE GET LAZY!----THEY DO NOT ACTUALLY DO THIS STUFF

IT BITES 'EM IN THE BUTT. THEY COULDA BEEN RIDING LONG AGO!

TAKE STUFF LOOSECLEAN"SCOOCH" THE CONNECTORS AROUND----TIGHTEN THE NUTS OR BOLTS WELL! DO NOT JUST PASS OFF ANY BIG CABLE CONNECTION AS, "IT LOOKS GOOD".

PAY SPECIAL ATTENTION TO THE BATTERY POSTS---CLAMPS---CABLE CONNECTIONS TO THE CLAMP (I'M TALKING ABOUT THE OLD STYLE "SQUEEZER" DEALEES, CLAMP TO CABLE)

IF YOU HAVE SIDE POST TERMINALS---TURN THE RUBBER INSIDE OUT/ REMOVE THE BOLT/ SCRUB THE FLAT CONNECTOR WITH A WIRE BRUSH OR SCRAPE IT WITH A KNIFE, TILL IT'S CLEAN---SAME FOR ITS MATING SURFACE ON THE BATTERY!

MANY TIMES THERE AIN'T MUCH SLACK IN THE CABLE----NO WHINING!---YOU GOTTA GET IT CLEAN, ESPECIALLY IF YOU CAN SEE "GREEN CRAP" CAKED ON 'EM!

YEAH, IT'S NOT EZ TO GET IN THERE, BUT LOOK AT WHAT YOU WILL GO THRU IF YOU DON'T!

THIS IS WAR--YOU GOTTA CHECK IT ALL--ANY CONNECTION---POSITIVE OR NEGATIVE THAT A BIG CABLE BOLTS TO. GET YOUR HANDS DIRTY!

IF A CABLE GOES TO A BOX--IT GOES ON THRU IT---CLEAN CONNECTIONS COMING AND GOING---TO WHERE EVER THEY GO!

EVENTUALLY YOU WILL REACH THE STARTER CONNECTION (POS)AND THE ENGINE/ BODY (NEG)

DON'T TELL THE SHOP, AS YOU GIVE 'EM YOUR $$$---WHILE WHINING---"I WAS TOLD TO CLEAN THAT CONNECTION, AND I DIDN'T!"

AS YOU PROGRESS, TRY TO CRANK HIM UP---YOU MAY FIND EXACTLY WHICH CONNECTION WAS THE PROBLEM!

I'VE SEEN THIS SAME CATASTROPHE, MANY MANY TIMES (I SAW IT YESTERDAY, AS I WAS ABOUT TO "CAR DOLLY" A FRIEND, THEN I DID THE CHECKS, IT WAS THE SIDE POSTS ON THE BATTERY CONNECTIONS). AND IT'S SO SIMPLE TO FIX. SAD THING, WHEN I GOT THERE, NOTHING HAD BEEN DONE 'CEPT AN ATTEMPTED JUMP START.I WAS GONNA HAVE TO PULL HIM 40 MILES, HE WASTED 3 HOURS OF MY TIME. LAZY, LAZY, LAZY

YOU COULD BE RUNNING BEFORE YOUR "CALVARY" ARRIVES!

THIS MAY HELP ALSO---STUFF YOU NEED TO KNOW ABOUT HOW SOME OF THE CJ STARTING SYSTEM WORKS. PICS THAT PERTAIN TO THIS ARE AT THE BOTTOM. THESE PICS ARE OF BOTH OF MY JEEPS

"OLD FORD TYPE" SOLENOID SYSTEM, YOUR ACCES, MAY VARY (This was really intended for Jeep CJ People!)

1) POSITIVE CABLE FROM BATTERY

2) OUT TO STARTER MOTOR

3) ON MY JEEP, THIS GOES TO THE ALTERNATOR

4) THIS FEEDS MY FUSEBOX (ALL OF MY ACCESSORIES)

5) "S" WIRE IS FROM KEY, 12V ONLY WHILE YOU ARE "CRANKING"

THIS WIRE ACTIVATES THE SOLINOID'S ELECTROMAGNET, WHICH IN TURN, CONNECTS---A and B INTERNALLY (ONLY THE 2 LARGE GAUGE CABLES CAN HANDLE THE AMPERAGE THE STARTER "PULLS").

WHEN THE SOLENOID IS ACTIVATED, IT THROWS 12V TO STARTER USING THE LARGE GAUGE CABLES (1) POS FROM BATT--THRU SOLINOID INTERNAL CONNECTION--(2) TO THE STARTER, WHILE KEY IS IN "CRANKING" MODE.

THIS IS THE TOTAL REASON FOR A SOLENOID, BECAUSE IT WOULD NOT BE PRACTICAL, TO RUN THE HEAVY CABLES TO AND FROM YOUR KEY SWITCH.

6)"I" WIRE (OPTIONAL), FEEDS COIL "FULL 12V", ONLY WHILE "CRANKING", AFTER YOU RELEASE THE KEY, THE COIL REVERTS BACK TO REDUCED VOLTAGE, SUPPLIED BY YOUR KEY IN THE "RUN" POSITION.

7) "SOLENOID MOUNT" GROUND, UNIT MUST HAVE A GOOD GROUND (BATT. TO ENGINE, ENGINE TO FRAME, FRAME TO BODY [ALL MUST CONNECT, SOMEHOW] )

(3 and 4, ON MY JEEP) ARE FUSABLE LINKS, ALL ARE NOT MARKED, MY #3 IS, #4 IS NOT. ITS SORT OF A "WIRE" FUSE.

IF THEY ARE GOOD, TUGGING ON THEM WILL BE JUST LIKE A WIRE, WHEN THEY ARE "BURNED UP", THEY WILL STRETCH OUT LKE A RUBBER BAND.

If your SOLENOID is good---Just not getting a "Signal" from the Key--We can test that too! (Then you will know which direction to chase this problem)

"S" is the wire that activates the Solenoid----we can sorta cheat it!

Regardless what you do to cheat it, You are suppling 12 VOLTS to the "S"('s) terminal on the solenoid. This is momentary as if you are cranking with the key

STAY CLEAR OF MOVING PARTS!IN PARK--OR EMERGENCY BRAKE ON!

I prefer a "Remote Starter Switch"

A Jumper wire momentarily touched or a Screwdriver touching POS BATTERY or POS BATTERY CABLE to the "S" terminal will by-pass the wire from the key

This will for sure let you know whether its a Solenoid problem or a Key (ignition switch not delivering 12 Volts)

This will start your rig if your key is in the "ON" Position

IF YOU HAVE A CJ 5 OR CJ 7---YOUR WIRES SHOULD BE HOOKED UP, EXACTLY AS MINE ARE, IN THE PICS!

JEEP CJ GUYS!--If you changed your coil and did not get the one that says, "FOR USE WITH EXTERNAL RESISTOR ONLY". You NEED TO GET THAT ONE! You have just "DOUBLED" your resistance (w/ one with a internal resistor), and DO NOT HAVE ENOUGH VOLTS TO MAKE IT FIRE! (Your resistor is a "RESISTANCE WIRE" going to the coil already!

MY LAST SOLENOID PIC WILL ONLY WORK IF YOUR SOLENOID IS HOOKED UP EXACTLY AS MINE ARE

Please Reply, Good or Bad, We will continue till you are running

THE MEDIC
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Wednesday, October 26th, 2011 AT 11:33 PM

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