Ignition Problem- UPDATED - Off-Road Forums & Discussion Groups
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post #1 of (permalink) Old 11-28-2002, 12:11 PM
DirtyBoy
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Ignition Problem- UPDATED

1977 CJ7 V8 Points Ignition

Jeeps been driving fine past 3 weeks its been on the road since rebuild. Went to get gas this morning, paid, turned the key and the starter would turn, but no spark. Fuel vapors are wisping out the side pipes but no spark. Towed to work, thank god for AAA. I had to swap out the steering column anyways so I did that. The column has a new ignition switch already on it. The points, condensor, coil, cap and rotor are 3 weeks old. If I put the volt meter in the spark hole in the coil it does get jumping voltage. If I put the voltmeter on the (+)Positive side of the coil key on, I get 12 volts. If I put the voltmeter on the (-)Negative side of the coil key on I get a roaming voltage of 4-7 volts. My tachometer does not go to 0 rpm when key is on either, obviously hooked up to negative side of coil; and thats what is making me think that there is not enough juice flowing through the coil due to a resistance problem to turn my tach on right...right? Is it my coil? It runs fine, and always starts immediatly when I start it normally. [img]images/graemlins/confused.gif[/img]HELP[img]images/graemlins/confused.gif[/img]
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post #2 of (permalink) Old 11-28-2002, 12:25 PM
**DONOTDELETE**
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Re: Ignition Problem- Hate wiring

Check all your grounds... thats where I would start.
post #3 of (permalink) Old 11-28-2002, 12:33 PM
DirtyBoy
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Re: Ignition Problem- Hate wiring

oh ya did that...glass tub=lots o' grounds. Also hooked up multimeter to points and there is the same roaming 4-7 volts also. Could the rotor be a problem to? There is no spark at the plugs with my inline spark checker.
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post #4 of (permalink) Old 11-28-2002, 12:35 PM
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Re: Ignition Problem- Hate wiring

Have you pulled the cap? The coil is sending spark to the Dist? [img]images/graemlins/smirk.gif[/img]
post #5 of (permalink) Old 11-28-2002, 12:38 PM
DirtyBoy
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Re: Ignition Problem- Hate wiring

yes there is a spark when I have the wire from the coil off the cap next to a ground.
post #6 of (permalink) Old 11-28-2002, 12:41 PM
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Re: Ignition Problem- Hate wiring

Sounds weird. You have fuel to carb, power to the coil going to the dist. How new is your ignition module? Check your rotor. Anyone got any other ideas. Anytime I ever had this problem it was either my ignition module or a ground. [img]images/graemlins/smirk.gif[/img]
post #7 of (permalink) Old 11-28-2002, 12:57 PM
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Re: Ignition Problem- Hate wiring

If you are getting a nice thin blue spark from the coil wire
- at the distributor end, everything up to there is OK.

Then the spark goes into the cap's center tower,
down to the rotor, then out the tip of the rotor
to a terminal, then out to the plug.

Sounds like it's getting "lost" on the cap somewhere.

Try pulling a plug wire out a little and cranking it.
If it can jump out of the tower to the wire it's OK in the
cap. If not pull the cap and look closely for somewhere
it's shorting. Look really close for a carbon trace on the
cap - a thin black or whitish line from the coil tower.
And look close under the center tang on the rotor for the
same. And under the rotor, bottom side for same.
If any, replace.

If it does jump out to a plug wire you may have already fixed
the problem, a loose connection etc. Now the plugs are just fuel
foulded from all your trying.

Pull the coil wire out of the distributor so it's about a
1/4" gap between the wire end and the terminal.
Start the engine, let it run like that a few moments till
the plugs clear, then push it back in again - done.

Let us know what you find on this thread.





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post #8 of (permalink) Old 11-28-2002, 01:08 PM
DirtyBoy
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Re: Ignition Problem- Hate wiring

Its getting-ready time for thanksgiving...but I will definatly check this out and I will get back to you tommorrow. Thanks to all.
post #9 of (permalink) Old 11-29-2002, 09:35 PM
DirtyBoy
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Re: Ignition Problem- Hate wiring

OK - hope everyone had a good turkeyday...Well today I went to look at the PITA and remebered my roomates CJ had a simular problem. On his I took the contact piece on the rotor and bent it up to a 30 degree angle, when I looked at his there it still was all bent up and running fine. So I bent up me rotor also and it [img]images/graemlins/grin.gif[/img]fired off [img]images/graemlins/grin.gif[/img]. Now it has a miss fire [img]images/graemlins/crazy.gif[/img]. So when I bent up the rotor tab a little more it contacted the cap on ignition and vibrated! so after shutting down the motor and rebent the tab I noticed the mesurement from the markings of the tab and the contacts in the distributor are more than a 1/8" away. I drilled out the rivit holding the contact in the rotor and moved it a 1/16" or so farther out. It now only misses on 1 cylendar, which is very eratic and undrivable on a 360. I am not telling you everything I did today but that is the jist of it. Not mentioning running to the part stores, work at the FD on and off...well it was 10:30 pm when my captain told me to give it a rest. So now at home I thought I would see if anyone had any ideas. Tomarrow Iam going to my brothers house to get my Jacobs Omnipack to up the juice to see if that can make it jump the gap better... I read and see alot about Hei or TFI upgrades for the 258's but what about the v8's???thanks.
post #10 of (permalink) Old 11-29-2002, 10:22 PM
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Re: Ignition Problem- Hate wiring

Looks like you answered your own question there. As RRich pointed out ..........you've got a rotor / cap problem. Replace both and ......if nothing else has gone south (you still have spark from the coil wire to ground) .......you WILL have a running engine (at least in regard to the ignition).

Point ignition systems are easy. You just need to verify the air/fuel/spark. You know you have fuel........you have spark out of the coil so the points and the rest of the primary is okay ...the only thing left (with very few exceptions) is the cap/rotor.

Since you had new parts so recently ..you may want to check the shaft runout on your distributor ...perhaps the bushings are shot causing you to have irregular rotor gap.

.......just thoughts.

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