79 CJ5 Ignition Problems

Alright troubles started the day I accepted the jeep for delivery. Jeep fired up fine the day I bought it and hasn't since. New battery, new starter, ignition coil, solenoid, ignition switch, and wires have been traced out. When I try to start the jeep I get nothing, no click of the solenoid, nothing! Everything else works though. All lights turn on wipers, blower fan. Any suggestions would be appreciated. Its been suggested that a relay is present somewhere in the circuit but I'm looking throught the wiring diagram and can't find it. I did find a wire from the ignition coil that's mentioned in the diagram as a jumper capacitor. Any clue as to what that is? There doesn't seem to be anywhere for that to go. Any bones would be appreciated.:?

 

Clarify, have you "traced" ignition switch, or did you replace it? Ignition switch failure seems most likely to me. Common, easy to fix. Located on top of the column toward the firewall. Actuated by rods coming down from the column key. They aren't rated for a whole lot of amperage and tend to go bad when other older components start drawing more than factory rating through it. I'd start there, and if it works, put an ammeter on it at start to see what your load is.

 

Did you replace the ignition relay? Did you try to jump the relay? A screw driver or jumper cable is great for testing it.

Its a cheap part and the engine will not even start to rotate if its bad.

Its located on the passenger side fender. It has 2 small 14 guage wires to control the relay's low side, and closes the circuit on the high side to connect the battery to the starter motor.

It would be my first guess as to whats wrong.

 

Does a 79 use a ford ignition control module on the bottom of the drivers fender?

Usually when they go the engine spins but no spark. It would be my second guess and its a cheap $25 part.

Oh and of course check the ground connection between the battery, the engine, and the frame. Lightrs will work with a "weak"ground, but engine will never start.

 

last idea, Does your jeep have a fuseable link wire? Piece of red wire to the ignition that acts like a fuse. It works great then just dies one day with out warning. You need an Ohm meter to test it, but its about a $5 to replace.

Personally I live dangerously and replace it with regular wire on ever car I've had problems with.

 

By "traced" I check for grounding with a multimeter with assistance from a wiring diagram. New ignition switch, solenoud, starter, ignition coil, battery. the "relay" on the passenger fender is what i'm calling a solenoid. Its new and i have yet to jump it with a screwdriver, or cables. Is there a nuetral safety switch on a manual tranny? as far as the fuseable link wire goes i have no idea. It doesn't ring a bell though.acording to the wiring diagram there is a wire off the positive side of the ignition coil that is labeled jumper capacitor, i don't know where or what that goes to. i really want to get this cranking before i pull the body off next weekend. thank you all

 

Lastly any thoughts on the Painless kit? Would it be a good idea to replace the computer next, that seems like the next step in what could be faulty:?

 

If its not cranking at all its probably more basic than a computer.

If your good with a multi meter I'd check for voltages at the relay/solenoid. Then the starter.

If you want to keep it simple. Check the ground between battery and the housing of the starter motor. If its good make sure the jeep in in neutral and if possible block the wheels.

First jump the relay/ solenoid basically connect the two large wires. You need a screw driver or thick wire. The starter should get 12 volts at the large wire. Take a small jumper wire and touch the small contact on the starter the starter motor will turn.

It won't run, but the motor will turn. If not you have starter problems.

Making the motor turn is simple. Ignition switch not sending power, solenoid/relay is bad. loose connection , bad starter or starter relay.

Getting the engine to actually run and not just crank requires more testing and could be the control module, coil, distributor pick up, no fuel, get the engine to turn first then worry about spark and actually running.

 

Your '79 shouldn't have a computer. :?

 

Don't forget to check for a good ground to the starter if everything else checks out. Place an ohm meter between the negative cable and the starter housing and see what it reads. It should be less than an ohm.

John

 

thanks... it'll have to wait til monday evening but i'll get it. by computer i mean the ignition module

 

well i've tried everything mentioned above to no avail. i did find a relay under the dash on the drivers side that i need to trace the wires out on but other than that i'm at a loss.