Troubleshooting Ignition Problems

Hey yall. I have run into a new problem with my ignition system and need some help. I have been messing with it for a few days no with no findings. I have a 73 cj-5 with the 304. Here is a list of new parts I have thrown at her to try to fix the problem: coil, points, and condensor (didnt have one on it to begin with). The main problem is I have no spark anywhere. Nothing at the plugs, nothing at the plug wire that goes from the coil to the distributor. I have good grounds at the coil and at the distributor. When I test voltage from ground to positive side of the coil I get anywhere form 5.6 vdc to 6.4 vdc. Also check the primary and secondary coils inside the coil and they are fine. I know Im gettin spark at the points because before I put on the condensor I was like a firework show when the points opened up. I hope Im not forgetting anything, but this thing has got me stumped.

 

I had the same kinda issue check your points spaceing maybe hook her up to a dwell meter, and than check the wires going to the coil. I thought i had mine hooked up all nice but i wacked it up good and it took me 2 weeks to figure it out that condencer thing was my problem i hooked it up all funny just check all your grounds and do you run a ballist resistor on your coil ... mine had it on there but i took it off. good luck

josh

 

If you're getting approx 6 volts at the coil with key-on/not-cranking, then your ballast should be good, since you're duplicating the run condition in that state. Can you crank your engine (i.e., the starter turns the engine over)? If you're getting 6 volts at the distributor while cranking, you've got a problem cause you want 12 volts when cranking. [In the unlikely event you do get 6 volts at the distributor while cranking, check the green wire to see if someone has cut a ballast resistor into the circuit. If you do find one, get back to us.]

If, as I suspect, you get zero volts at the distributor while cranking the engine, check the I terminal on your starter solenoid to see if you get 12 volts there when cranking. If not, you probably need a new solenoid. If you are getting 12 volts at the I terminal, then your solenoid is doing its job and you need to check for continuity in the green wire that comes off the solenoid's I terminal and connects to the coil positive terminal. I suspect either the green wire is bad or you have a bad connection to the green wire at either the solenoid or the distributor.

If your engine won't crank, first check the connections at the battery cables and the solenoid. If turning on the ignition switch lights up the gauges in your dash, then check the voltage at the S terminal of the solenoid. If no voltage, you've got a problem somewhere either in the starter switch, or the red wire going to the ignition switch from the positive side of the solenoid, or the light blue wire coming back from the ignition switch to the S terminal (or one of the various connections). If you get 12 volts at the S terminal and your motor won't crank, then your either your solenoid is bad, or you've got a bad solenoid ground, or you've still got a poor connection at/between the battery and the solenoid or between the solenoid and the starter, or your starter is bad. Find/fix the above and then you should be able to crank the motor over and proceed with checking out the I terminal on the solenoid as described in the preceding paragraph.

[Somebody needs to doublecheck me on this--it's been a long time!] Good luck and let us know what you find.

John

 

sounds right to me. i had to replace just about everything to get mine to work at http://new.photos.yahoo.com/crackerjax27526 there "might" be some under hood photos of my jeep that have photos of the wires going to and from the coil that may help you?? i cant be sure there is any but hope it helps.

 

Ck the roter I have seen some go bad and will let the spark ground out through the center to the shaft.

 

Double check johnb's post and verify wiring is correct; 2 wires to (+) post of coil; 1 from starter solinoid, other is resister wire from ignition switch. (-) post of coil to distributor (and tach if installed). The key statement you made was "Here is a list of new parts I have thrown at her to try to fix the problem: coil, points, and condensor (didnt have one on it to begin with)." And, "I know Im gettin spark at the points because before I put on the condensor I was like a firework show when the points opened up."
I'm not sure what condenser you put on, but that seems like the main suspect???

 

Dumb question, 6 VDV while running on the + side of the coil?

 

Good question. The 12 volts provided by the system is choked down to 6 volts at the coil to increase the longevity of the points. They burn out faster than we would like at 12 volts.

John

Note: I had a much more elegant response all ready to go, but the system logged me off before I could post it. I get the message: Brevity is good!

 

Alright fellas, thanks for all the help. Alright first things first, the engine cranks with no problems at all. Checked voltage at I terminal on the soleniod, with 6 vdc not cranking and 9.5 vdc cranking. This is also the same on the positive side of the coil 6vdc not cranking, 9 vdc Cranking. Alright now at the distibutor I have a 0vdc when not cranking, and 6vdc when cranking. Also I inspected the wiring and just with any 30+ year old vehicle it doesnt look that good. Wires cut and twisted back together and then electrical tape over them to hold them together. I also didnt see anything in the wiring that might be a ballast resistor.

I forgot to mention that I did replace the cap and rotor.

 

Like lost dawg said, I would suspect your new condensor, could be grounded out to the distributer housing, also where are you testing your voltage at the distributer? You say you have 6v at the dist., should run with that

 

Im testing the voltage at the distributor at the terminal that has the neg wire that comes from the coil. Is this right? Also the condensor is brand new. The jeep didnt even have one in it until now. The only other thing I can think of that might be causing me problems is the plug wire that goes from the coil to the cap. Other than that Im not sure. I just want to get this jeep running again so I can drive it onto a trailer so I can tow it to the other garage so I can restore it. I plan on upgrading the ignition system anyways, I would just like to know that I have a running machine before I go ripping and tearing for a new body and wiring upgrade and many other things.

 

Okay, if you've checked the coil to distributor plug wire for continuity (resistance should measure approx 5,000 ohms per foot IIRC) and clean terminals, then we move on. Straight from the Haynes manual...

3. Remove the distributor cap and rotate the engine until the contact points are closed. Install the cap and turn the ignition on.

4. Connect one lead of the voltmeter to the primary terminbal on the coil [use the - side] and the other lead to the distributor coil terminal. If the voltage drop exceeds the Specifications [.05 volt], check for a corroded or loose connection.

5. Connect one lead of the voltmeter to the primary terminbal on the coil [use the - side] and the other lead to a good ground on the distributor body. If the voltage reading [emphasis added] exceeds the Specifications [.05 volt], the points are misaligned or the point connections are loose.

6. Remove the distributor cap and open the points. The voltage reading should rise to close to the battery voltage. If the voltage is low, there is a short circuit in the distributor.

7. Disconnect the condenser lead, open the points and check the the voltmeter reading. If the reading jumps to full battery voltage, there is a fault in the condenser and it should be replaced with a new one. If the voltage does not jump, replace the distributor with a new or rebuilt unit.

8. Connect the voltmeter to the battery negative post and a good ground on the distributor body. With the points closed there should be virtually no drop in voltage (very little deflection of the voltmeter needle). If there is a significant voltage drop, clean and tighten the battery posts.

9. Check for a similar voltage drop between the the distributor body and a good ground on the engine block. If there is a voltage drop, remove the distributor and clean the mounting surfaces of the distributor body and block.

[And that's all that Haynes has to say.]

Personally, I'd first pop a known good plug wire in the coil and see if that gives me a spark out of the coil, and if that didn't make any difference then I'd proceed to items 8 and 9 before I did the other tests. And rather than a new distributor, I'd carry the distributor out of the CJ to an auto electric shop and let them find the problem if the distributor failed the second part of test item 7 (it'll probably just be a faulty insulator).

Good luck.