Jeep cranks, but won't start

CREWMASTER1

MEMBER
18 POSTS

Alright. I tried, again, hooking the post battery to the pos coil and still got crank, but no start. Without the direct hookup, I could still detect electricity (with the meter that just lights up) in the wire from the coild to the distributor and in a spark plug wire from the distributor to the actual spark plug. I tried to visually check for spark in the wire running from the coil to the top of the distributor and couldnt see any spark but it shocked the hell out of me, so I'm assuming it works. A giggled the wires while cranking and got no change. I again tested voltage at the positive side of the coil while cranking and get 500mVolts and then get 0.5volt with the key in the run position. Unfortunately I have a trip planned to the beach for 3 days, leaving soon. Was going to take the jeep, but no going to happen so just taking the SUV. I'll have to get back on Thursday eve for some more playing around.

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Tuesday, July 24th, 2012 AT 6:45 PM

CREWMASTER1

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I just cant stop messing with it. I tried again to hook up the old ignition (like described in the my post before last) no change. I can get the jeep to start as long as I keep the key turned all the way forward in the START position and floor the gas.I got it to rev to 3000RPMs for a few seconds, but as soon as I let go of the key and it returns to the run position the thing dies!

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Tuesday, July 24th, 2012 AT 7:07 PM

CJ MEDEVAC

MECHANIC
11,005 POSTS

OK BOSS

WE'RE GONNA HAVE TO GET SERIOUS NOW!

IT'S "TOUGH LOVE TIME".......SUCK IT UP!

NO MORE ABRA-CADABRA....POOF.....MAGIC TRICKS!

SO FAR

YOU HAVE 2 TECHS AT $0.00 PER HOUR

WE DON'T NEED THE MANUAL YET---BUT I CAN MAYBE TELL YOU PAGES TO GO TO LATER IF NEED BE

YOU NEED ONE OF THESE SO WE CAN CONTINUE....HAVE TO! WE CAN EXPLAIN HOW TO USE IT IN MANY WAYS

http://www.harborfreight.com/7-function-digital-multimeter-92020.html

OR THIS

http://shop.advanceautoparts.com/webapp/wcs/stores/servlet/product_digital-multitester-multimeter-actron_9090000-p?searchTerm=multimeter

OR WHATEVER!....DIGITAL IS BETTER THAN ANALOG (SWEEPING NEEDLE)

I HAVE JUST SAVED YOU A BUNDLE....IT'S YOUR TURN......CUT YOUR NEIGHBORS LAWN.....TAKE YOUR CANS TO RECYCLE.....YOU NEED $7 (THAT'S SEVEN BUCKS FOR ALL OF YOU CIVILIANS!)

NOW GIVE ME 50 AND ONE FOR THE GREAT AIRBORNE RANGER IN THE SKY!

I MAKE MY FIVE YEAR OLD GRANDSON WORK TOO!....HE FOLLOWS DIRECTIONS WELL....THESE ARE 16" WHEELS.....HE DID IT ALL EXCEPT FOR BREAKING THE NUTS LOOSE

VERY IMPORTANT QUESTIONS:

1) HAVE YOU OR YOUR EVIL BUDDIES PULLED THE DISTRIBUTOR OUT SINCE THIS PROBLEM HAPPENED?

2) WITH THE DISTRIBUTOR CAP OFF AND DANGLING TO THE SIDE---WHEN YOU CRANK THE ENGINE OVER, DOES THE ROTOR BUTTON TURN?

3) FORCEFULLY, BUT GENTLY ENOUGH AS NOT TO BREAK THE PLASTIC ROTOR BUTTON.....CAN YOU TURN THE ROTOR BUTTON AND IT'S SHAFT WITH JUST YOUR FINGERS?....A LITTLE CW AND CCW "SLOP" OR "PLAY" IS NORMAL...... THE SHAFT TURNING IS NOT!

YOUR TURN

THE MEDIC

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Wednesday, July 25th, 2012 AT 2:05 AM

RASMATAZ

MECHANIC
75,992 POSTS

Starts at cranking position and dies when you let go the key-sounds like you need to triple check/test the ignition switch and if it has a resistance wire check that too-

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Wednesday, July 25th, 2012 AT 4:02 AM

CJ MEDEVAC

MECHANIC
11,005 POSTS

LOOKS LIKE THE POS BATTERY TO POS COIL WOULD HAVE MADE IT GO

MAYBE WITH HIS SET UP----HE SHOULD TRY IT AGAIN---BUT "REMOVE" ANYTHING ELSE OFF OF POS COIL----JUST HAVE BATTERY ONLY JUMPED TO IT (THIS MIGHT ELIMINATE A "POSSIBLE" DEAD SHORT IN THE RESISTANCE WIRE)

I FEEL SURE WHAT MAKES IT BUST OFF DURING CRANKING IS THE "I" TERMINAL IS DOING IT'S JOB

IF IT RUNS---REALLY LOOK OVER EVERYTHING BACK DOWN THE RESISTANCE WIRE ALL THE WAY TO THE IGN SWITCH FOR A SHORT

THE MEDIC

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Thursday, July 26th, 2012 AT 4:08 AM

CREWMASTER1

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18 POSTS

Answers to your VERY IMPORTANT QUESTIONS:

1) HAVE YOU OR YOUR EVIL BUDDIES PULLED THE DISTRIBUTOR OUT SINCE THIS PROBLEM HAPPENED? No, never pulled this out.

2) WITH THE DISTRIBUTOR CAP OFF AND DANGLING TO THE SIDE---WHEN YOU CRANK THE ENGINE OVER, DOES THE ROTOR BUTTON TURN? Yes, it spins around in circles!

3) FORCEFULLY, BUT GENTLY ENOUGH AS NOT TO BREAK THE PLASTIC ROTOR BUTTON. CAN YOU TURN THE ROTOR BUTTON AND IT'S SHAFT WITH JUST YOUR FINGERS.A LITTLE CW AND CCW "SLOP" OR "PLAY" IS NORMAL. THE SHAFT TURNING IS NOT! There is a little play, but nothing excessive, feels normal.

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Thursday, July 26th, 2012 AT 11:27 PM

CREWMASTER1

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18 POSTS

Based on the trouble shooting in the jeep manual you gave me online. See page C 62, the voltage is low at the positive coil terminal, so I need to disconnect the "capacitor wire terminal" and recheck the voltage. What and where is the capacitor wire terminal?

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Friday, July 27th, 2012 AT 12:49 AM

CREWMASTER1

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18 POSTS

I'm so confused. If the the problem is somewhere in the ignition aspect before the power gets to the coil (as evidence by low voltage at the coil) why won't the jeep run when I directly take power to the coil by a positive jumper form the battery?

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Friday, July 27th, 2012 AT 1:26 AM

CJ MEDEVAC

MECHANIC
11,005 POSTS

THAT IS THE EXACT QUESTION THAT WE ARE PONDERING!

THIS IS WHY I WANTED THE COIL HOOKED TO THE BATTERY ONLY. AND THE WIRE THAT TRAVELS BACK TO THE "ON POSITION" OF THE KEY COMPLETELY LOOSE FROM THE COIL/DISTRIBUTOR

AGAIN!--YOU DID SAY IT STARTS (BUSTS OFF) WHILE IT IS CRANKING. BUT WILL NOT REMAIN RUNNING WHEN YOU RELEASE THE KEY. IS THIS 100% CORRECT INFO?

IN THAT SHORT PERIOD, DOES IT SEEM TO RUN WELL, OR IS IT BACKFIRING/ STAMMERING/ SKIPPING?

IF THIS IS THE CASE AND IT SEEMS TO RUN FINE---IT REALLY SEEMS LIKE THE COIL IS OK AND THE TIMING IS TOO

I'VE BEEN LOOKING AT THE '84-'86 WIRE DIAGRAMS

AND ALSO MY '79 DIAGRAM----SO FAR, THE ONLY CAPACITOR I SEE IS "CAPACITOR JUMPER" IN THE '79 IT IS A SHORT WIRE OFF OF THE POS SIDE OF THE COIL CONNECTOR (I THINK IT'S PURPOSE WAS TO CUT DOWN RADIO STATIC)

I'VE NOT SEEN THE INSTRUCTION SHEET YOU POSTED A FEW ANSWERS BACK---IT'S HARD TO MAKE ALL OF IT OUT

I'M GONNA SEND YOU A MESSAGE (TOP OF THE PAGE CLICK ON YOUR NAME, LOOK LEFT FOR MESSAGE CENTER) I'LL GIVE YOU MY EMAIL---IF YOU WOULD, "SCAN" THE COMPLETE INSTRUCTIONS AND SEND THEM TO ME

AS FAR AS THE OTHER QUESTIONS I ASKED (1), (2), (3) WHAT ARE THE ANSWERS?

WHAT ABOUT A FUSE SEARCH--ANY OF 'EM BLOWN?

I KNOW THIS IS A PAIN. HANDS ON, MUCH OF THIS COULD BE DIAGNOSED IN 10-20 MINUTES AND WE WOULD HAVE ELIMINATED SO MANY POSSIBILITIES

THE BAD THING IS, WE CANNOT SEE WHAT KIND OF MODS WERE DONE IN 28 YEARS TIME OR SOMETHING CONNECTED WRONG, ETC

SOMETIMES A QUICK GLANCE AROUND AND SUDDENLY YOU SAY, "THERE IT IS RIGHT THERE!"

I'M NO FACTORY TRAINED FELLER---I HAVE HIGH SCHOOL AUTOMOTIVE SHOP (2 YRS)/ ELECTRICITY SHOP (1 YR)/ (METAL) MACHINE SHOP (2 YRS) IN MY EXPERIENCE (1978-1982), US ARMY AIRBORNE RANGER ('82-'87), 1-1/2 YEARS IN AN AUTOMOTIVE MACHINE SHOP/ ENGINE BALANCING, AND PLUMBING SINCE 1990

SO YES, YOU CAN CALL ME AN "EXPERIENCED DIYer". NOT AMC FACTORY TRAINED GUY

ALL THE WHILE, I SORTA HUNG OUT WITH THE BIG KIDS WITH CARS FROM ABOUT AGE 10 AND UP AND STARTED PICKING UP ON HOW CARS WORK--THIS CONTINUED ON FOREVER, AND I HAVE BEEN "UP KEEPING" MY CJs, EVER SINCE I GOT MY 1ST. PRESENTLY HAVE #s 6 AND 7.I HAVE NEVER OWNED A "CAR" FOR MYSELF AS AN EVERYDAY DRIVER

I HAVE MEGA EXPERIENCE, I HAVE BEEN COMPLETELY THRU EVERY PIECE OF MANY, WORKING ON MINE AND CJs FOR OTHER FOLKS.I'M THE GUY EVERYONE RUNS TO WITH THEIR CJ PROBLEMS

NOW DAYS, I DON'T DO IT "FOR THEM", I MAKE THEM LEARN AND DO IT THEMSELVES---USUALLY AT MY HOUSE WITH MY TOOLS!

MINE DO NOT EVER GO TO "SHOPS", EXCEPT FOR "WHEEL ALIGNMENTS"

WE WILL GET YOU FIGURED OUT! IT MAY TAKE SOME TIME AND I HOPE YOU ARE UNDERSTANDING THE STUFF I'M DISHING OUT

I NEED YOUR ANSWERS!

THE MEDIC

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Friday, July 27th, 2012 AT 3:42 AM

CREWMASTER1

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THIS IS WHY I WANTED THE COIL HOOKED TO THE BATTERY ONLY. AND THE WIRE THAT TRAVELS BACK TO THE "ON POSITION" OF THE KEY COMPLETELY LOOSE FROM THE COIL/DISTRIBUTOR ---This is what I did, took everything off the coil pos terminal and went direct from the battery. Won't start.

AGAIN!--YOU DID SAY IT STARTS (BUSTS OFF) WHILE IT IS CRANKING. BUT WILL NOT REMAIN RUNNING WHEN YOU RELEASE THE KEY. IS THIS 100% CORRECT INFO? I have tried it several times. It will crank and start, it is cold so it runs a need some fuel, so as long as I keep the key in the start position and give it some gas it revs up no problem, then dies as soon as I let go of the key. I haven't run it for more than about 5 seconds, but it goes.

IN THAT SHORT PERIOD, DOES IT SEEM TO RUN WELL, OR IS IT BACKFIRING/ STAMMERING/ SKIPPING? It needs a bit of fuel, but it usually does when cold. It runs though.

IF THIS IS THE CASE AND IT SEEMS TO RUN FINE---IT REALLY SEEMS LIKE THE COIL IS OK AND THE TIMING IS TOO---I think it is related to the ignition switch possibly. I may try to replace it tomorrow, but it looks a little challenging.I actualy think I may just buy a new one, connect it and see if I can use a screwdriver to start the thing rather than the rod from the key.

I'VE NOT SEEN THE INSTRUCTION SHEET YOU POSTED A FEW ANSWERS BACK---IT'S HARD TO MAKE ALL OF IT OUT

I'M GONNA SEND YOU A MESSAGE (TOP OF THE PAGE CLICK ON YOUR NAME, LOOK LEFT FOR MESSAGE CENTER) I'LL GIVE YOU MY EMAIL---IF YOU WOULD, "SCAN" THE COMPLETE INSTRUCTIONS AND SEND THEM TO ME

AS FAR AS THE OTHER QUESTIONS I ASKED (1), (2), (3) WHAT ARE THE ANSWERS? See above post.1-no, 2-yes, 3 little play, nothing major.

WHAT ABOUT A FUSE SEARCH--ANY OF 'EM BLOWN? I have looked at all fuses I can find.I don't see any fuses that run in the ignition system. Under the dash there are fuses for horn, lights, etc. All of those systems work so I haven't pulled each one out, but all other fuses I can see are good).

I KNOW THIS IS A PAIN. HANDS ON, MUCH OF THIS COULD BE DIAGNOSED IN 10-20 MINUTES AND WE WOULD HAVE ELIMINATED SO MANY POSSIBILITIES

THE BAD THING IS, WE CANNOT SEE WHAT KIND OF MODS WERE DONE IN 28 YEARS TIME OR SOMETHING CONNECTED WRONG, ETC. The only mods I know of are the Nutter bypass (which bypasses the ECM which is all timing crap) and the MSD ignition (There is a quick disconnect that reportedly allows me to revert to the jeeps original ignition system by reconnecting a few plugs, I tried this and it didn't help at all, so I'm thinking the problem is before the ICM---I'm thinking ignition switch or some wiring crap under the dash).

SOMETIMES A QUICK GLANCE AROUND AND SUDDENLY YOU SAY, "THERE IT IS RIGHT THERE!" I've taken a glance around many times, from under/above/behind every location I can think to look I have. I've even done it in the dark with a headlamp to make me focus right where I'm looking. Can't see a thing wrong.

I NEED YOUR ANSWERS!

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Friday, July 27th, 2012 AT 5:00 AM

CJ MEDEVAC

MECHANIC
11,005 POSTS

I STILL WANT YOU TO SCAN THE INSTRUCTIONS AND SEND THEM TO ME

THE MEDIC

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Friday, July 27th, 2012 AT 7:19 PM

CREWMASTER1

MEMBER
18 POSTS

I FIGURED IT OUT!
It was a coil fuse! Despite me thinking I tested all the fuses! I hooked up the new ignition switch and that didn't fix the problem. So, I basically followed the wires from positive side of the coil back to the firewall and tested for continuity. That was intact. But there was no continuity from the firewall to the ignition switch. So after dissecting all under the dash and following the wire, I followed it to a simple coil fuse that was blown! I guess now the question is why did it blow? I'm guessing when I hit the bump something shorted for just a second and blew the fuse. I'm thinking I better carry a few extra fuses with me on the road and if this continues to happen I better do some more investigation!