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Unread 11-05-2013, 10:43 AM   #16
itw69
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1976 CJ5 
 
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Location: Knoxville, TN
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Pictures of the engine compartment showing the ignition hardware.

img_1061a.jpg   img_1062a.jpg   img_2645a.jpg   img_2654a.jpg  
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Unread 11-05-2013, 10:44 AM   #17
John Strenk
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Getting closer,
Electronic could be Prestolight or Duraspark.
Prestolight usually has a stamped steel housing and the Duraspartk has a Cast aluminum housing.

How you check them are vastly different. the 12 Volts running to the coil should not be the same as the 12 volts going to the distributor.

But since it ran at one time, we should not worry about it being wired correctly. Unless you changed the wiring when installing the new distributor. I see no reason to do so.


Missed the picture... Must of posted it up when I was typing
That is a prestolight ignition system.

Make sure that ICM is well grounded, they usually have a separate ground wire coming out of it. Trouble with Prestolight is that you can have power to everything but if the ICM is not grounded nothing is going to work. Unlike the Duraspark were the ground is through the distributor and the case does not have to be grounded so rusty mounting bolts on't bother it.

Make sure the fender has a good ground also but if the starter solenoid is working then I'm sure it has a good ground.
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Unread 11-05-2013, 10:56 AM   #18
John Strenk
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I'll have to rack my brain a little as I dumped my prestolight years ago for the Duraspark.

But lunch is over so I'll dwell on it a little and see if anything sparks to life when I'm thinking....

Usually if it ran and sat and no spark, it's usually a corrosion problem in one of the connectors.

Any troubleshooting guise for a Prestolight ignition system will help, I think Oleo Jeep has a 76 FSM online you can use.
Look it up and read over the trouble shooting steps for the Prest-o-light ignition system.
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Unread 11-05-2013, 11:10 AM   #19
itw69
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Quote:
Originally Posted by John Strenk View Post
Getting closer,
Electronic could be Prestolight or Duraspark.
Prestolight usually has a stamped steel housing and the Duraspartk has a Cast aluminum housing.

How you check them are vastly different. the 12 Volts running to the coil should not be the same as the 12 volts going to the distributor.

But since it ran at one time, we should not worry about it being wired correctly. Unless you changed the wiring when installing the new distributor. I see no reason to do so.


Missed the picture... Must of posted it up when I was typing
That is a prestolight ignition system.

Make sure that ICM is well grounded, they usually have a separate ground wire coming out of it. Trouble with Prestolight is that you can have power to everything but if the ICM is not grounded nothing is going to work. Unlike the Duraspark were the ground is through the distributor and the case does not have to be grounded so rusty mounting bolts on't bother it.

Make sure the fender has a good ground also but if the starter solenoid is working then I'm sure it has a good ground.
I will check that when I get home, thank you for the brain dump. I appreciate it.
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Unread 11-05-2013, 11:10 AM   #20
itw69
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Quote:
Originally Posted by John Strenk View Post
I'll have to rack my brain a little as I dumped my prestolight years ago for the Duraspark.

But lunch is over so I'll dwell on it a little and see if anything sparks to life when I'm thinking....

Usually if it ran and sat and no spark, it's usually a corrosion problem in one of the connectors.

Any troubleshooting guise for a Prestolight ignition system will help, I think Oleo Jeep has a 76 FSM online you can use.
Look it up and read over the trouble shooting steps for the Prest-o-light ignition system.
my lunch is over as well, thank you...I will check per your direction.
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Unread 11-05-2013, 11:14 AM   #21
zillla
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Looks like a Prestolite to me. Had one in my 75. At 25000 original miles the engine died and would never restart. Replaced the ignition module and started right up. I have since replaced this ignition entirely, and may have a spare module aropund.
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Unread 11-05-2013, 11:20 AM   #22
JeepHammer
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Throwing 'Parts' at a problem that is in the wiring harness won't do much...

How about some pictures or descriptions of the ignition system you are running?
We don't know where the 360 came from, and it could have several different ignitions, and that complicates testing...

The 'BEST' thing I can tell you is... without knowing which system you are running...

PLASTIC vacuum advance is Prestolite Distributor, Prestolite ignition system. These have a proprietary trigger and can't be 'Mixed & Matched' with parts from other systems. Round Coaxial wire with two wire plug at the end from distributor...

Metal vacuum advance with 'Cone' shaped vacuum can behind the vacuum nipple is a DELCO distributor, usually breaker points inside, and since you said you had a 'Module', the likelihood of you having breaker points on a module is slim... Single wire from distributor...

If you have a METAL vacuum advance, with 'Flats' like a nut behind the vacuum hose nipple, that's a Motorcraft distributor and is intended to be used with a DuraSpark module. Should have three wires coming out of it...

1. Flip the distributor cap, have someone crank the engine while you put some load on the rotor.
This will tell you if the distributor/camshaft gear are doing their work or not. You don't have to 'Gorilla' the rotor, just some backpressure to tell if the camshaft gear and distributor gear are working...

Then I would pull the #1 spark plug, crank engine to 'Compression Stroke', and HAND TURN the engine until the timing mark on balancer lines up with the ZERO mark on the crank...
Then check to see if the rotor is pointing at the #1 spark plug wire or not.

It's VERY COMMON to get a new distributor in with the timing off at the camshaft gear. Most people don't take into consideration the gears are helical cut and the rotor position will change as the gears engage...

If the rotor is pointing at #1 spark plug wire while crank is at TOP DEAD CENTER of #1, ZERO on the timing tab, then move on...

---------

2. Pull the 'Positive' or 'Red' wire off the coil.
While CRANKING the engine, see if you get a 'Bright' test light reading on the WIRE.

3. With the ignition switch in the 'Run' position, see if you get a 'Bright' or any light at the same 'Red' wire.

This will tell you if the power is getting from the ignition switch, through fuses, through the connectors to the ignition coil and rule out some wiring glitch under the dash.

4. Replace the 'Red' wire to the coil,

5. Connect your test light to the battery POSITIVE, (you are checking for 'Ground' at this point, so you need POSITIVE current to make the light work)
Pull the 'Black' or 'Green' wire (Depending on system, it could be either color) off the ignition coil and test the WIRE.

Have someone crank the engine. The light should 'Flash' on and off. If it doesn't flash, the module isn't switching the coil like it should...

6. With key switch 'ON',
There is a 'Red' wire going to the module, check the HARNESS side for power to make sure the module is 'Hot' so it can work.
If you don't get power to the 'Red' wire (harness side) the module isn't getting power.

(Use a small piece, single strand or two, of wire inserted into the correct color wire socket to access for testing)

7. There will be a 'GREEN' wire from module to ignition coil, Plug the module in, use tip above to access for testing, test the 'Green' wire at the module while engine cranks.
Again, you are testing for 'Ground', so you will have to connect to battery POSITIVE for this one.

If it flashes, you have a bad connection from module to coil. If it doesn't flash, the module or trigger in the distributor is bad, or wiring connections are bad...

8. Prestolite will have a 4 wire square plug, and a single black wire that connects to 'Ground'.
Make sure that black single wire is getting a good 'Ground', this will keep the ignition from working...

I usually run a dedicated ground wire to the module, helps keep that Prestolite module alive and working...

This will narrow down your issues to wiring under dash, module/distributor trigger, or wiring in engine bay.
Unplug both module and distributor, test those two wires with ohm meter, and to 'ground', make sure they aren't 'Grounded' or broken someplace...

Once module is plugged back in, connect a GROUNDED 'Test Plug' to the coil wire (Instead of distributor cap), and unplug the distributor two wire connector,
Short over from one wire to the other with a 'Jumper' wire, when you pull the jumper wire away, you should get ONE spark if the module is working,
OR, If that doesn't work (Depending on what module type you have, there are two), You can try grounding each wire to the block, one at a time. When the ground connection breaks, you should get a SINGLE spark if the ignition is on and the module is hooked up and working... Only one of the two wires will make the spark, and I can't remember which color right off the top of my head, the other one will do nothing, so test both a few times... Just TOUCH and release, don't solidly ground the wires...

If the test plug sparks, you have a bad distributor trigger.
If the module doesn't spark, you have a bad module or wiring between distributor and module...

Does this help or is it too pushy?
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Unread 11-05-2013, 11:31 AM   #23
JeepHammer
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Pictures posed while I was typing, It's a PRESTOLITE, no question...

RED wire comes from ignition switch to coil, then down to module.
Green wire goes to ignition coil 'Negative'
Black wire at module is supposed to be 'Grounded', and a dedicated 'Ground' wire is always recommended. Sheet metal, paint, rust, ect. always causes issues.

The two other wires, usually either yellow, white, blue, depending on which type of module you have, anyway, there will be two and they go to the distributor trigger.

4 wire plug should have Red (power into module), Green (ground for ignition coil) and two other wires for distributor signal...

Here is a quick test...
Use a test plug (Grounded) in the top of the coil where the coil wire is supposed to be. Old spark plug with 'Ground' wire wrapped around the threads and grounded back to the battery...

Use a JUMPER wire from battery positive to ignition coil 'Positive' (RED) wire terminal.
Just SPARK the positive terminal and see if you get ONE spark each time you contact the positive post.
Unhook NOTHING from the small wires to the coil...

You should get ONE spark from the test plug when you 'Spark' the positive terminal on the coil...
If you DO get that one spark from the test plug, it's probably wiring under the dash or out to the module/coil.
Of you DO NOT get one spark each time, then it's probably coil or module, or wiring in between coil and module...
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Unread 11-05-2013, 11:51 AM   #24
Matt1981CJ7
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Here's the consolidated version of the testing procedure I use:

1. Test for spark at the plugs.

2. If no spark at plugs, test for spark at coil-to-distributor wire.

3. If the coil wire has spark, then the dizzy cap, rotor, plug wires, or plugs may be defective.

4. If there's no spark at the coil wire, check the voltage and primary resistance of the coil (1-2 Ohms) and the resistance of the coil-to-dizzy wire (500 Ohms per inch).

5. If the coil and coil wire check out, check for 12v to the ICM (2-pin connector).

6. If there's 12v to the ICM, check the pick-up coil resistance (400-800 Ohms), at the 4-pin connector.

7. If voltage and resistance all check out, replace the module.

Hope this helps,

Matt
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Unread 11-05-2013, 12:00 PM   #25
itw69
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Quote:
Originally Posted by JeepHammer View Post
Pictures posed while I was typing, It's a PRESTOLITE, no question...

RED wire comes from ignition switch to coil, then down to module.
Green wire goes to ignition coil 'Negative'
Black wire at module is supposed to be 'Grounded', and a dedicated 'Ground' wire is always recommended. Sheet metal, paint, rust, ect. always causes issues.

The two other wires, usually either yellow, white, blue, depending on which type of module you have, anyway, there will be two and they go to the distributor trigger.

4 wire plug should have Red (power into module), Green (ground for ignition coil) and two other wires for distributor signal...

Here is a quick test...
Use a test plug (Grounded) in the top of the coil where the coil wire is supposed to be. Old spark plug with 'Ground' wire wrapped around the threads and grounded back to the battery...

Use a JUMPER wire from battery positive to ignition coil 'Positive' (RED) wire terminal.
Just SPARK the positive terminal and see if you get ONE spark each time you contact the positive post.
Unhook NOTHING from the small wires to the coil...

You should get ONE spark from the test plug when you 'Spark' the positive terminal on the coil...
If you DO get that one spark from the test plug, it's probably wiring under the dash or out to the module/coil.
Of you DO NOT get one spark each time, then it's probably coil or module, or wiring in between coil and module...
Thank you for your very detailed overview and explanations. I will run these tests and see where I end up.
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