CJ3A Direct Short Battery to Block: Ignition Issues

Good Morning,
My name is Chris and over the past ten months I’ve been doing a frame off restoration of a ’51 CJ3A (serial 451-GB1 23480) with the help of the forum as a reference. I’ve now re-assembled the Willy’s with your help and had the Jeep running with good power and acceleration.

A month ago, my original 6V foot actuated starter finally gave up. I was replacing it with an IMI High Torque IMI-134-002 when I accidently bridged the High Voltage + terminal of the starter to the block with a socket extension (ugh).

Engine: Re-built L-134 (Compression in cylinders ranges between 100 and 110)
Fuel Pump: Facet Posi-Flo EFP-3 (Generating 2 psi of fuel pressure)
Carburetor: Solex 32PBIC single barrel downdraft
Starter: IMI-134-002 Gear Reduction starter
Distributor: Omix 12V Solid State (Kaiser Willys 923068)
Coil: Standard Motor Products UC15T (Resistance checks OK across primary and secondary coils)
Ignition cables: New 7mm High Temperature
Alternator: Delco 12V 3 Wire Configuration

Needless to say, this was the beginning of an electrical diagnostic journey which has led me to replace:

1) Both the terminal lugs (+ and -) at the battery. The current partially melted the negative lug resulting in an intermittent ground (that was a joy to find).
2) The ignition switch (intermittent continuity at the BAT terminal to the other posts)
3) The original coil and distributor ignition module. (Due care)

At this point all of my accessories (lights, horn, fuel pump, gages, dash light) all function normally again. My starter is cranking the engine nicely but it does not start with these symptoms:
1) Plugs are wet and I can smell fuel when cranking.
2) I’ve pulled #1 plug and have no spark.
3) I have 11.8 Volts between the positive terminal of the coil and BAT negative when cranking.
4) I’ve pulled the spark wire from the coil to the distributor and checked for spark to ground during cranking….no spark.
5) The resistance across the positive and negative terminals of this new coil is 3.9 ohms.
6) I’ve checked the resistance in my spark wires and plugs…all seem nominal.

I’m stumped and would appreciate any suggestions you all may have to restore spark to my plugs.

In Him,
Chris in Spring Hill, TN

"The original coil and distributor ignition module. (Due care)"

I'd guess, in an old fashioned system, that you had a point/condenser issue. If you have an electronic distributor module, I'd be very suspicious of it.

I think Larry has you in the right direction. I am also wondering about the ignition module on that electronic distributor.

When you lost the ground after the short, it is possible it caused some stray voltage to the module. Maybe LarrBeard will explain further what happens when you lose ground in a "solid state circuit".

I was able to replace the electronic "module" but not the inductive pickup. Could errant voltage have affected that as well? Is there any way to diagnose the function of these components?

Good Evening. Tonite I replaced the old distributor with a brand new distributor...regrettably, still no spark. I still have 11.8V at the coil during cranking. I'm really at a loss to know what to check/work on next to get this Jeep to start. Any suggestions?

Chris exactly where are you measuring 11.8V? Where are the black and red leads from the distributor hooked? What else if anything is hooked up to the coil? Is there a Tachometer wired in? Can you take a photo of the setup?

I’m measuring the coil voltage from the + pole of the coil and the negative post of my battery: 11.8V. The black lead of the distributor is connected to the negative post of the coil and the red lead is connected to the positive post of the coil. I’ll send a picture in the morning. Thanks for your help!

Good deal Chris. I also would like you to measure the resistance to ground from the coil body itself to the battery negative. Then disconnect the ignition module (distributor) wires from the coil. With no wires on the terminals of the coil, what is the resistance to ground between the Neg terminal of the coil and Battery Neg and the Positive terminal of the coil and battery Negative?

Attachment 10477

There is infinite resistance (no continuity or resistance at my meter’s 20M ohm setting) between the coil housing and battery ground. The same is true for both measurements (+ and - coil posts) to BAT - with the coil completely detached: open circuit - infinite resistance.

First time posting a pic here. Trying from my iPad and it looks like it just posted a thumbnail. Please let me know if you need more.

Chris the coil body is grounded at the engine block. It is probably the blue coating providing the insulator to ground. I was trying to be sure the engine is well grounded. Just to be sure check from the distributor housing casting to the Neg battery terminal, there should be 0 ohms. The distributor has to be grounded. Since the starter is turning over, I expect it is OK. Next check the coil wire for impedance. The coil wire should be around 5,000 to 10,000 ohms per foot if it is a resistor core wire. It will be much less if the wires are spiral core.

If it passes the above I can currently think of only one more thing. Pull the distributor cap off and verify that the rotor is turning when the motor is spinning.

The distributor housing has continuity to the negative pole of the battery and the coil wire (appx 1ft) is at 6600 ohms. The rotor is turning.

Should the coil housing be grounded to the block? As you indicated, it is not. Do you think it should be?

I need to thank you again for your help. I'm just out of ideas and appreciate any thoughts you have.

You are welcome, this is a bit baffling.

It is possible the coil needs to have the housing grounded, usually it is not necessary.The distributor housing must be grounded. If the block is grounded, the distributor housing had also better show 0 ohms read on a very sensitive scale. The ground from the block to the battery must be large and a very good connection. If the ground is poor, when you hit the start, the current draw will be through other places as well as the poor connection. If it draws the smallest amount of ground current through the ignition module, it will ruin it. The distributor housing to the neg terminal of the battery needs to read 0 (Zero) Ohms.

For what it's worth, I concur.

The coil ground connections are returned through the (-) terminal of the coil - down through the points or electronic switch that does the point function - to chassis (engine block) ground.

Good Morning,

And again, thanks for your each of your thoughts. I've inspected and cleaned up all of my ground strap connections (neg to body and block)...they all looked solid and oxidation free to start with. My resistance from distributor housing to battery negative reads .1 ohms on my most sensitive scale (200K Ohms).

I just ran a jumper from battery negative to the distributor housing and attempted to start....no spark.

Chris, we have covered it all. You must have a rash of bad distributor ignition modules. Do you have the original distributor around? The only other components that are left would be the Rotor and the Cap. Make sure the Rotor hasn't found a path to ground.

"... .1 ohms on my most sensitive scale (200K Ohms)...."


In this measurement, the most sensitive scale to check a really low resistance would be the R x 1 or R x 10 scale. What do you measure from distributor (-) to battery negative?

I measure .1 ohms when I touch the probes of my ohmmeter together. I get .1 ohms from my distributor to battery neg. 200K is my most sensitive setting. My wife would probably agree....I'm not sensitive enough:-)

I do have the old distributor. I've never had the jeep running with that. I think new points and condenser would be in order. I've never set gap on point. I'll need to research that.

Chris I’m not real sure but you are going to wear yourself completely out on this topic:cool:
I’d throw the original distributor in the ole girl and call it good when she fires up and purrs like a kitty cat!!

Points and condensers aren't as evil as some say. They worked for 100 plus years, and are pretty simple. Magnetic pickups and the Wizardry of modern technology can give you grief especially when blended with the old.

A quick and dirty points gap method is to use a match book cover, or .020" on the feeler gage if you want to be precise.

Chris there is one thing that I can think of left. Are you checking the voltage at the positive terminal of the coil while the engine is cranking?

Run a wire (very temporarily) from the battery + to the coil +. Turn it over and see if it starts (has spark). If it does not start what is the voltage at the positive terminal of the coil while it is cranking?

Quote:

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Originally Posted by bmorgil

Chris there is one thing that I can think of left. Are you checking the voltage at the positive terminal of the coil while the engine is cranking?

Run a wire (very temporarily) from the battery + to the coil +. Turn it over and see if it starts (has spark). If it does not start what is the voltage at the positive terminal of the coil while it is cranking?

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Thanks You, bmorgil!!

After working on reconditioning my points/condenser distributor this past week in preparation for swapping out the distributor. I tried to start the Jeep one last time with the electronic ignition using your suggestion of running a jumper from positive battery to the positive post on the coil and EUREKA! I started seeing spark right away and before I could turn it off the engine started on three cylinders. After letting it idle for a moment, I turned it off and tried to restart with no luck. However, when I put the jumper on, it fired up again.

Since then, I've removed the jumper and started it several times with no problem. I'm using the same gage of wire on the jumper that I have going to and from the ignition switch.

Can you give me your thoughts on what's happening here?

And again, thank you.

There are a number of possibilities:

A. A miswire. The wire to the + terminal of the coil may not originate where you think it does.

B. An improperly crimped terminal lug. My replacement harness had a lug crimped to the insulation, not to the conductors. It took me several years to find it.

C. An actual broken wire – kinked or crimped and broken.

D. Maybe a defective or miswired ignition switch … and so on;

It kind of degenerates into a bug hunt now. At least you know you have a good distributor.

Go find that bug.

Follow Larry's guidance here. Follow A,B,C,D and let us know. You now need to find the intermittent voltage to the coil. One of the things Larry has pointed out above that you need to know, is your Jeep wired according to the original wiring diagram? Are you using the foot pedal starter or is the stater converted to a solenoid?

Its great that you reconditioned the old one. gm wouldn't be without his points and in the event of an EMP attack, your Jeep will run with that distributor!

A word of caution here, you should not put a solid state electronic device into a circuit with unknown voltage situations. Bad connections can ruin it. Find out why and how to get 12 volts to the coil while it is cranking first. Then hook the distributor back up.

In addition to what Larry posted I will add bad solder joints. All soldered splices and terminal ends would be suspect if anyone has been near the vehicle with a soldering iron. There is no way to visibly tell a good solder joint from a bad one if not corroded or broken.

Quote:

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Originally Posted by LarrBeard

There are a number of possibilities:

A. A miswire. The wire to the + terminal of the coil may not originate where you think it does. [I've traced the positive coil wire back to the ignition post on my ignition switch. The voltage on my coil + is a steady 11.6V during cranking.

B. An improperly crimped terminal lug. My replacement harness had a lug crimped to the insulation, not to the conductors. It took me several years to find it. The hunt has started and is ongoing.

C. An actual broken wire – kinked or crimped and broken. Given what I've shared on this to date, can I limit this search to the path of current to the coil?

D. Maybe a defective or miswired ignition switch … and so on;

It kind of degenerates into a bug hunt now. At least you know you have a good distributor.

Go find that bug.

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Thanks again to all for your assistance. Given that I still have good voltage at the coil + post, is it possible that I'm just not passing enough current to the coil due to a flakey connection? BTW, I'm back to a no spark condition this morning, which is kind of a blessing since I'm looking for a bad connection. Other than visually inspecting every cable terminator in the jeep, is there a more discrete way to narrow the search?

I'd appreciate any thoughts...in the meantime...the bug hunt continues.

Use your Mult-Meter and chase it down. I have money riding on the ignition switch but, there are other possibilities. Yes it is possible that you have a bad connection. Since you know it runs with the jumper wire, you could replace the wire completely from the ignition "Run" terminal to the coil. Make sure if you are using the foot starter pedal the "Start" terminal, if you have one, is not used. There should be nothing hooked to it. If you are using a solenoid the wiring is different. If a new wire does not work replace the switch.

Are you using the foot pedal to engage the starter?

If you still have wire directly connected to the battery and no spark:

A. Look at the (-) terminal of the coil with a meter while you are cranking. When the points are open, the (-) terminal should read 12-volts. When the points close, the terminal should read ground. If you always read ground - either the points are not opening and closing or you have an open coil. Since you are back to a real distributor and it ran for a bit - I don't suspect that it just went bad.

B. If you are back to vehicle wiring - not just a direct wire - and you have 12-volts on the (+) terminal while you crank - I suspect a coil issue even more!

This just checks the primary side, there is a way to check the secondary (high voltage) side:

The old redneck way to test a coil was to touch a clip lead on the (-) terminal to ground with the points open. If the top of the coil had 12-volts and that didn't get you spark - the coil was bad.

Bubba would have Junior hold the lead that went to the center of the distributor cap and if Junior jumped and cussed - you probably had a good coil.

With all of the shyte you are seeing - it's about time to swap out the coil for a known good one.

Quote:

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Originally Posted by CChris

i n preparation for swapping out the distributor. I tried to start the Jeep one last time with the electronic ignition using your suggestion of running a jumper from positive battery to the positive post on the coil and EUREKA! I started seeing spark right away and before I could turn it off the engine started on three cylinders. After letting it idle for a moment, I turned it off and tried to restart with no luck. However, when I put the jumper on, it fired up again.

Since then, I've removed the jumper and started it several times with no problem. I'm using the same gage of wire on the jumper that I have going to and from the ignition switch.

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Larry, he got it to run with a jumper to the coil and the electronic distributor. I think he is saying he is back to no spark with the jumper off and using the key again?

Clarify that for us Chris.

Quote:

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Originally Posted by bmorgil

Larry, he got it to run with a jumper to the coil and the electronic distributor. I think he is saying he is back to no spark with the jumper off and using the key again?

Clarify that for us Chris.

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Good Morning,

Since my the unfortunate incident where I shorted the starter + post to the block while changing out my defective foot pedal actuated 6V starter. I have installed a new, solenoid operated 12V starter, and replaced the following with new components:

1) Negative and Positive battery cable lugs
2) Solid state distributor
3) 12V Ignition Coil
4) Ignition Switch

Items 1 thru 4 were done while I attempted to get good spark on my #1 plug with no luck. At no time, through all of these trials have I seen anything less that 11.5V on the + Coil post during cranking.

On Sunday, using bmorgil's suggestion, I was able to start the jeep when I used a jumper from the battery+ to the coil+ post. After turning it off, I removed the jumper and was unable to start or get spark. When I put the jumper back on, the jeep started. After idling for 15 minutes, I turned the jeep off, removed the jumper and it started without the jumper several times. After remounting the ignition switch into the dash, I took it out for a 30 minute drive and when I had it back in the barn, I stopped and restarted it another 5 times with no jumper. I closed the barn, went to the house and had a beer.

On Monday morning, I attempted to start the jeep with no joy. I pulled #1...no spark. Checked my coil voltage during cranking: 11.6V. I applied the jumper from the battery+ to the coil+....no spark.

Since my volt meter isn't showing me where the problem is, my current plan is to disconnect everything but the ignition circuit (e.g. lights, horn, amp meter, fuel gage, fuel pump, alternator) and redo all crimped connections in the ignition circuit on the assumption that I have a faulty connection which shows good voltage but can't carry current reliably. This includes the following cables:
1) Battery + to Amp Meter+ post
2) Amp Meter - post to Ignition Switch BAT post
3) Ignitions Switch IGN + post to Coil
4) Ignition Switch STARTER post to starter solenoid + post

Again, thanks to each of you for your patience and thoughts on this issue. I was reminded on Sunday how much I enjoy driving this old Willy's and look forward to doing it again soon.

Please let me know if any of this recap is unclear.

I agree with your faulty connection theory. It sounds to me like it works when warm but not when cold. Had an airplane do that with the charging system. Fly for a while with everything working then the charging system would just die. 10-15 minutes later it would come back. Impossible to troubleshoot like that. My fix was to rewire the airplane. The problem should be in the circuit or circuits you bypassed to get spark.

Quote:

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Originally Posted by LarrBeard

If you still have wire directly connected to the battery and no spark:

A. Look at the (-) terminal of the coil with a meter while you are cranking. When the points are open, the (-) terminal should read 12-volts. When the points close, the terminal should read ground. If you always read ground - either the points are not opening and closing or you have an open coil. Since you are back to a real distributor and it ran for a bit - I don't suspect that it just went bad. It was running on the electronic ignition distributor...sorry if I didn't make this clear

B. If you are back to vehicle wiring - not just a direct wire - and you have 12-volts on the (+) terminal while you crank - I suspect a coil issue even more!

This just checks the primary side, there is a way to check the secondary (high voltage) side:

The old redneck way to test a coil was to touch a clip lead on the (-) terminal to ground with the points open. If the top of the coil had 12-volts and that didn't get you spark - the coil was bad.

Bubba would have Junior hold the lead that went to the center of the distributor cap and if Junior jumped and cussed - you probably had a good coil.

With all of the shyte you are seeing - it's about time to swap out the coil for a known good one.I have replaced the coil since I shorted the battery, that doesn't guarantee its good but it is the one that was in the jeep when it was running 2 days ago.

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I'm sorry if this wasn't clear in the thread...regrettably it's a long one.

I've re-terminated every connection in the ignition circuit, removed all non ignition related circuits and attempted to start the jeep with and without the jumper and still no spark. I still have 11.6V on the coil + when cranking and have probed the hot lead in the distributor to assure I'm getting voltage there (not while cranking, however).

Chris, make sure there is at least 10 volts at the coil while cranking. If there is pull the distributor. Put the points distributor back in. If you want an electronic distributor, buy the Pertronix conversion for your original distributor. There simply is no other explanation for your issue. The Pertronix will be trouble free and you can retain the original look.

Quote:

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Originally Posted by bmorgil

Chris, make sure there is at least 10 volts at the coil while cranking. If there is pull the distributor. Put the points distributor back in. If you want an electronic distributor, buy the Pertronix conversion for your original distributor. There simply is no other explanation for your issue. The Pertronix will be trouble free and you can retain the original look.

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Thanks, bmorgil. I came to the same conclusion last night. I've been working on the old distributor this morning with the goal of getting it in and giving it a try by tomorrow. It's been a real education for me. Seems like a real simple system which could provide more diagnostic feedback than the electronic "black box". I'll let you know how it goes either way. Again, can't thank you enough for all of your help.

After putting the original (points & condenser) today, I appear to have reliable spark for now. I'll update this after a couple of days to confirm that holds. I'm working on adjusting the timing and getting my wiring buttoned up. Again, thanks to all.

Chris, it is important to verify that you have at least near 10 volts while cranking. Any less and two things can happen. The coil will not saturate and generate a spark and the ignition module will not fire. If your ground has resistance or is of insufficient size, or there is resistance in the wiring somewhere the cranking voltage at the coil will be low. The only way to verify this is to draw maximum current (crank the starter) and check the voltage drop at the coil +. It must be near 10 volts minimum or there will be no spark. All electronic distributors have a minimum firing voltage. Points are not sensitive to it but the coil is. The coil is not as sensitive as the electronic module. You could still have the root cause of your problem lurking.

Quote:

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Originally Posted by bmorgil

Chris, it is important to verify that you have at least near 10 volts while cranking. Any less and two things can happen. The coil will not saturate and generate a spark and the ignition module will not fire. If your ground has resistance or is of insufficient size, or there is resistance in the wiring somewhere the cranking voltage at the coil will be low. The only way to verify this is to draw maximum current (crank the starter) and check the voltage drop at the coil +. It must be near 10 volts minimum or there will be no spark. All electronic distributors have a minimum firing voltage. Points are not sensitive to it but the coil is. The coil is not as sensitive as the electronic module. You could still have the root cause of your problem lurking.

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Interesting...with the points/condenser distributor I'm now getting 10.6V from the + coil post to the - battery post during cranking (with a good white spark). The electronic ignition was always showing 11.6V at the coil (but no spark). By the way, the jeep is running now, I need to wait for my son to come over this weekend to finish tuning. I need his hands, eyes and brain to keep from doing something stupid (e.g. leaving a tool laying near the positive starter terminal).

I'm really at a loss to know why the electronic distributor wasn't sparking with that voltage. Perhaps it's not as easy as poor Chinese quality control? At any rate, I'm investigating the PerTronix Electronic conversion kit you mentioned. I'm a little spooked by OMIX at this point. The OMIX distributor that wouldn't spark was brank new and had not been exposed to "the short"

I'll know this weekend if I'm officially out of the woods, but the signs are good so far. Either way, I'd really like to buy you and the other contributors a beer sometime. If you're ever in Nashville, drinks are on me:)

Chris