Ignition trouble with cj7

[fyr196]

I'm working on a 1980 CJ7 with the v-8 304. This Jeep has been parked for 3 months with ignition turned on. I replaced the battery and tried to start it. It cranks but no spark. I checked the plugs they look good but no spark. I checked the coil, no spark going out of it. I checked the wires going in to the coil and found power. I replaced the coil and still no spark. I was looking all over trying to figure it out when I saw two wire harnesses without an attachment. Turned out to be the Ignition Module. I bought one and the CJ fired right up. It ran a few seconds and shut down. I checked all connections and tried again. Fired right up for the second time. It died shortly after and when I tried to start it again I was back to no spark. I plan on getting another Module but I want to know if anyone has had the same problem or knows what might cause the upset in the system.
Thanks

 

[jay79cj7]

RE: On this Memorial Day 2005: A Gift For Al Queda

Check the voltage at the coil. It should be around 9V or so. If its too much, it can fry the module.
By the way, the module I picked up from Autozone has a lifetime warranty, which may come in handy with ignition wiring problems.

 

[wm69]

go over to jeepsunlimited and there's a thread running right now on ign modules and it has a wiring diagram on putting a GM HEI module in place of the jeep module. The GM module will hold up a lot better than the stock Jeep module.......

 

[fyr196]

jay79cj7 - When you say check the voltage at the coil, do you check it going in or coming out. If the voltage is too high what should I check or replace? I'm still learning. I bought the 1st one at Auto Zone for about $26.00. I got the lifetime warranty on it. I'm glad I did.

wm69 - If I go the way of the GM what do I gain with this mod over the OEM module? I saw the post on the other site, thank you for all your help.

 

[jay79cj7]

RE: National Anthem

Check the voltage of the red wire going to the coil to ground. There is a ballast wire (or should be) that steps the voltage down. Read through that other post of mine that we PM'ed about, it should explain. Let us know what you find.

 

[wm69]

Re: RE: National Anthem

wm69 - If I go the way of the GM what do I gain with this mod over the OEM module? I saw the post on the other site, thank you for all your help.

GM module will supposedly hold up better (longer) than the stock unit, which is notororious for crapping out. I was kinda ticked when the guy "rigged" my jeep up with a new module (he just bolted it to the passenger fender) but it's been that way for a long time and I haven't had any trouble out of it. I found out about swapping the GM module in when I was researching the resistor. Some people think running 12 V to the coil will give a better spark (which makes sense to me). The factory system has a resistor built in which allows 7 or 9 (can't remember) to the coil, so you're not getting all the power to your coil. You can cut the resistor out of the system, but that will in short time kill the factory ign module. The fix to this was to replace the weak facotry ign module with a GM HEI module which will hold up to the higher voltage. Hope that helps...

 

[jay79cj7]

Is it just a GM HEI module, or is it the entire distributor assembly? I was under the impression that it was the entire distributor that needed to be swapped for the HEI mod.

 

[wm69]

Is it just a GM HEI module, or is it the entire distributor assembly? I was under the impression that it was the entire distributor that needed to be swapped for the HEI mod.

You can swap in the whole HEI dist assembaly that would include the module, OR you can do the TFI mod and only swap in the GM ign module (like the module that is used with the HEI system). (least that's how I think it goes, my GM module's on my hunting jeep at my parents' so I can't get a part # till the end of the month when I go down there again).

 

[fyr196]

I exchanged the ignition module, got a new one, checked the voltage at the coil and it read 7. I,m at a loss. I have a fear the guy before me put a kill switch in. What would I look for and how could it start for a few soconds if it had one? Does anyone have any ideas? To go the way of the GM HEI, what do I need? Could you post part numbers when you get them?

 

[wm69]

I exchanged the ignition module, got a new one, checked the voltage at the coil and it read 7. I,m at a loss. I have a fear the guy before me put a kill switch in. What would I look for and how could it start for a few soconds if it had one? Does anyone have any ideas? To go the way of the GM HEI, what do I need? Could you post part numbers when you get them?

You SHOULD have 7 at the coil. That's because of the resistor in the power wire going to the coil. With only 7 your factory ign module shouldn't fry again (unless you got a bad one) anytime soon. If you were to take out the resistor (the wire going to your coil actually IS the resistor as it will only carry 7 volts from what I've read) you would be running 12v to the coil, which would supposedly give you more spark. Running 12V to the coil WILL fry your ign module, unless you upgrade to the GM module. The way it is now should work fine. IF you want to try running 12V to the coil and hope you get a hotter spark THEN you need to get a GM module. If it runs well enough for you as-is I'd just leave it alone.

Edited to add, leaving your vehicle with the engine not running and the ignition in the "on" position is a sure way of frying an ign module. Don't do that........

 

[fyr196]

WM69
The problem is it doesn't run. With all I have done in the past few weeks it still turns over but no spark? Do you know of any other problems I could have missed. I did notice another thing today. I was looking in the Haynes manual and saw that my CJ should have a clip on the coil, but under my hood is 3 wires. 1 on the positive side and two on the neg. Not including the center Ing. wire going to the Distributor. Any ideas?

 

[jay79cj7]

RE: Re: RE: National Anthem

One wire should be red and is the 7-9V hot that you already checked. Another should be green and this will lead back to your ignition module. Is the third attached to the red's terminal or the green's? Do you have an aftermarket tach? If so, I believe the tach signal is the green terminal of the coil. If you have a stock CJ tach, then this is not the case. If this 3rd wire is attached to the red's, then it may be (guessing) a ballast bypass wire. A ballast bypass does just as it's named; it bypasses the ballast wire to give a full 12V at the coil for starting only, and then drops back down to 7-9V in the run position.

How did you check the voltage at the coil if it won't stay running? With the key in the run position, or start position?

I see you are in northern IL... Where abouts?

 

[fyr196]

The Wire going into the + side of the coil is red. Then two are going into the - side. I do have an aftermarket tach. I had the jeep in the run position when I checked the coil.

Round Lake IL.

 

[jay79cj7]

Round Lake... I used to work at Baxter.

I am out of ideas for now. Keep letting us know what you find. I'm sure you have already done this, but I would trace all the wires and make sure that they are all hooked where they are supposed to be and not damaged, etc.

 

[fyr196]

RE: Re: RE: Re: RE: National Anthem

Thanks for everything I think I might break down and let a real mechanic give it a try.

 

[fyr196]

I fixed it!!!! It was a bad wire connection between the distributor and the coil. I think it is called the "coil pick up", or something. Well now I have extra parts.

Thanks again for all your help.

 

[mud4feet]

RE: nutter bypass...

I fixed it!!!!.....................................

YAAAAAA!!!!!!!!!!! Don't it feel great! Always remember that you're no dumber than the dumba$$'s they hire at the stealership!! Perserverence pays!!!!!! Congrats.


dumba$$ mud

 

[jay79cj7]

RE: motorcraft...

Good, congrats!