1978 Jeep CJ5 Ignition Problems

Perform the tests in pics to see why ignition system doesn't spark. Then recheck your work with new wiring as something may be wrong with way it was hooked up.

NO SPARK?

PIC 1) WHAT IS THE VALUE HERE AT POSITIVE COIL, WITH THE KEY ON?

PIC 2 AND 3) WHAT HAPPENS IF YOU CONNECT POS BATTERY TO POS COIL AND ATTEMPT A START?

PIC 4) THE TESTER FOR THE IGNITION MODULE AT ADVANCE AUTO PARTS, TEST IT AT LEAST 5 TIMES IN A ROW. IF IT'S BAD, TEST YOUR NEW ONE BEFORE YOU LEAVE THE STORE. I'VE SEEN MULTIPLES IN A ROW, RIGHT OFF OF THE SHELF BEING DEFECTIVE! OTHER STORES HAVE TESTERS TOO!

I HAVE MANY MORE PICS TO AID WITH

HAVE YOU HAD THE DISTRIBUTOR OUT? (I CAN RUN YOU THRU PUTTING IT IN CORRECTLY)

'78 WAS SORTA WHEN THEY WERE TRANSITIONING FROM PRESTOLITE IGN TO MOTORCRAFT. IN YOUR PICS, YOURS IS DEFINITELY MOTORCRAFT. IF YOU THINK YOUR COIL IS WRONG, ASK FOR A COIL FOR A 1979-1986 CJ-7 (THEY QUIT MAKING THE CJ-5s IN 1983) THE COIL YOU WOULD NEED REQUIRES EXTERNAL RESISTANCE. THE ORIGINAL HARNESS HAS A "RESISTANCE WIRE", I'M GUESSING THAT THE BALLAST RESISTOR IS TAKING THE PLACE OF THAT (OTHERWISE YOU WOULD HAVE BOTH, WIRE AND BALLAST, PIC 1 SHOULD TELL THAT STORY)

LET'S KEEP THE COMMO GOING TILL YOU GET HIM FIXED! I'M HERE MOSTLY AFTER 6 PM EASTERN EVERY EVENING

TEST RESULTS/ ANSWERS TO QUESTIONS?

THE MEDIC

ANOTHER DAY WITH YOU JEEP NOT ON THE ROAD IS ALMOST SACRILEGIOUS,

ANY SORTA UPDATE ON WHAT'S GOING ON?

THE MEDIC

With key on you should not have 12 volts t coil it shold be like 9 you only get 12 volts when you hit start on ignition. Recheck your wiring that you have done i'd bet there is a problem there or resistor is burnt up. Also making the ground wire hot did something. I sent instructions on how to check module on very first reply. Check ballast resistor by volts shold be 12 on one side and lower on other. Like 9 or so maybe even 6 but it shold be about 9

THIS MAY SOUND A BIT UNSCRUPULOUS

MOST PEOPLE FINALLY TAKE A SMALL SCREWDRIVER AND TRY TO TAKE THE IGN MODULE LOOSE- THIS USUALLY RESULTS IN BREAKING THE LOCKING TABS OFF :-(

THE MANUAL SAYS TO GRASP THE WIRES ON EITHER SIDE OF THE CONNECTOR AND PULL.

YEP, IT WORKS!

LIKE Hmac300 SAID, YOU SHOULD BE GETTING REDUCED VOLTAGE AFTER THE CURRENT PASSES THRU THE BALLAST RESISTOR W/ KEY "ON"

MAYBE YOU HAVE VOLTAGE COMING TO THE COIL FROM THE "I" WIRE FROM THE SOLENOID ("I" SHOULD ONLY BE "HOT" [FULL BATTERY VOLTAGE] ONLY WHILE CRANKING) JUST REMEMBER "I" WIRE WILL HAVE THE REDUCED VOLTAGE WHEN NOT CRANKING. AS IT "TEEs" ONTO THE IGN WIRE AND WHATEVER VOLTAGE IT IS, IT WILL ALSO BE! (SOUNDS CORNY, DIFFICULT TO EXPLAIN)

'NUTHER WORDS MAYBE THAT END IS WIRED WRONG

I'M GIVING YOU A DIAGRAM AS TO HOW THIS ALL WORKS, PAY ATTENTION TO THE "TEE" AT THE COIL) "I" IS SORTA JUST A "BOOST" TO THE COIL DURING START UP

I HAVE A 2 PAGE COLORED WIRE DIAGRAM FOR A '79 IN "MY PICTURES" (WHICH SHOULD BE REALLY CLOSE) I BLEW IT UP AND HAVE IT HANGING ON MY WALL. LET ME KNOW IF YOU NEED IT

KEEP US POSTED

THE MEDIC

YOU ARE GONNA SEND US A PIC OF YOUR BABY AREN'T YOU?

THE MEDIC