No spark

Tiny
SOFTPICKLE
  • MEMBER
  • 1974 JEEP CJ5
  • 5.0L
  • V8
  • 4WD
  • MANUAL
  • 107,739 MILES
Hello all. Currently, I am working on the vehicle listed above. According to the VIN number, it came out with a 258 six cylinder but had a 304 V8 engine swap done prior to my purchase of it. Recently, I disassembled the vehicle down to the frame to inspect for any cracks in the frame. Fortunately all I found was it needing new motor mounts. I have reassembled it and am now currently having problems with it getting spark. I took pictures prior to disassemble and have hooked everything back as my pictures had and now I have no spark.

The main problem I have experienced is since someone did the engine swap prior to me, is the wiring is not color coordinated now. This vehicle was running prior to being disassembled but now I am having the no start issue.

I have ohm tested the coil and the positive and negative poles ohm out at 2.4 and positive and high output pole tested out at 11,500 ohms. From what I have read, I may have a bad coil. Any other help is greatly appreciated as to what could be causing my problems.
Tuesday, July 25th, 2017 AT 2:30 PM

22 Replies

Tiny
CARADIODOC
  • MECHANIC
  • 33,864 POSTS
Forget testing the ignition coil. The numbers in the service manual are for reference only, to give you an approximate idea of what "normal" is. Half of the properly-working coils you measure will fall outside that acceptable range. Also, unless a terminal was physically damaged during the prior disassembly, the coil didn't fail from just sitting.

Do you have breaker point or electronic ignition? Start by measuring the voltage on the positive terminal of the ignition coil with the ignition switch turned on. See if it changes while you slowly rotate the crankshaft by hand. Next, measure that voltage again during cranking. Tell me what you find.
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Tuesday, July 25th, 2017 AT 4:02 PM
Tiny
SOFTPICKLE
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Voltage to the positive side of the coil remains at 12.4 with key on and turning crank by hand. When cranking, voltage drops to 9.5 volts on positive side of coil. This engine does have points and a ballast resister.
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Tuesday, July 25th, 2017 AT 5:05 PM
Tiny
CJ MEDEVAC
  • MECHANIC
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I am going see where you go with this Doc!

Wife in the hospital, I am on an ancient laptop, good many of my pictures and diagrams are on the mega computer at at the house.

Gotta know SOFTPICKLE, Do you really Love your Jeep?

The Medic
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+1
Tuesday, July 25th, 2017 AT 6:49 PM
Tiny
SOFTPICKLE
  • MEMBER
  • 21 POSTS
I have had a jeep ever since I could drive. When I sold my first one, I lasted three months before I had to have another one and I have had one ever since. I have always wanted to have a CJ and now I have one so to say I love my jeep would be an understatement. I have been working on this CJ for about two years now putting money in it whenever the wife allows.
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Wednesday, July 26th, 2017 AT 7:07 AM
Tiny
CJ MEDEVAC
  • MECHANIC
  • 11,004 POSTS
Has this puppy run at all since you have had it/ or installed this engine?

Have you had the distributor out of it? Or anybody?

Does it even cough or spit? Or is it just empty dry over and overs?

Can you list any modifications that have been made that could affect this situation?

Is this your 1st point system Jeep?

Me too! Got my 1st '77 CJ-5 in '81. Five more CJ-5s along the way. And then "Willy" My '46 Willys.

At present, my last '77 CJ-5 ("Mr. Jeep") and "Willy", Got both of 'em in 1991.

Always my daily drivers.

The Medic
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Wednesday, July 26th, 2017 AT 2:10 PM
Tiny
SOFTPICKLE
  • MEMBER
  • 21 POSTS
The engine swap was done before I bought this jeep. That being said, the wiring is completely custom so it doesn't match what came from the factory. It was running before I pulled it into the garage to disassemble it. When I did disassemble it, I took grille and fenders off then body then removed engine and transmission as one unit. I did not mess with the distributor. This is my first jeep with points but I have multiple tractors that use them. I have unhooked a spark plug and there is no spark when the engine cranks. I have checked the points and assured they are opening and closing as the distributor turns. There have been no modifications to the electrical system. I have only added headers and side pipes.
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Wednesday, July 26th, 2017 AT 2:54 PM
Tiny
CJ MEDEVAC
  • MECHANIC
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Just for giggles,

Disconnect "POS" coil wire,

Connect w/ a jumper wire (alligator type if you have 'em) from "POS" Battery to "POS" Coil.

Don't worry about the ballast resistor for this test.

Give it a whirl!

(My 258 in pics below)

Results?
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Wednesday, July 26th, 2017 AT 5:26 PM
Tiny
CARADIODOC
  • MECHANIC
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Measure the voltage on the ignition coil's negative terminal, then watch what it goes to when you rotate the crankshaft by hand. It should go to 0.0 volts when the points are closed, and full battery voltage when they're open. If you check for spark at the end of the coil wire, you should see a healthy spark there, and a small spark at the points, when they open up. If you don't see the spark by the points, disconnect the condenser, then try again. You can work the points by hand too instead of constantly turning the crankshaft.
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Wednesday, July 26th, 2017 AT 5:27 PM
Tiny
SOFTPICKLE
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  • 21 POSTS
With the key on, negative coil terminal is 12V. While turning the crank, the negative side does not change. No spark at points either. Condenser has 12V and distributor has good ground.
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Thursday, July 27th, 2017 AT 11:11 AM
Tiny
CJ MEDEVAC
  • MECHANIC
  • 11,004 POSTS
On my Willys, when I got him ready to run for (my) first time.

It was a no go for hours and hours, NO SPARK!

I had assembled the point system just like they had come out!

(This may be why he was set out to pasture)

I finally noticed the bolt/ screw that held the spring steel/ brass/ the fork of the condenser was just a hair too long.

The darn thing was contacting the inside of the distributor housing and grounding the whole deal out!

Sounds like you may have something "OPEN" with your points.

Maybe use a voltmeter set to OHMs and do continuity tests. See where the points lose ground when they are closed.

One end of the point system should ground to the distributor (probably tiny rivets) Maybe they are corroded? Maybe a little "Backing Up" and a punch might make them ground again?

The other end of your points will be isolated from the distributor body with a small plastic/ or material like an electronic board.

Might wait on Doc's Opinion, another brain!

To me it (unless the points are dirty, or not fully closing) looks like you are never getting a ground signal thru the points when they close.

You can also upgrade to an electronic system at a reasonable cost. I'm showing below how I did mine. Real EZ, quickly can be reversed! The manufacturer has made them specific to bunches of different distributors, only two wires from the distributor to the coil to connect!

I hope I'm dead on with the corrosion theory!

The Medic
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Thursday, July 27th, 2017 AT 3:59 PM
Tiny
SOFTPICKLE
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I cannot figure out how to remove the peice the button bolts to. It looks like it is connected to the whole distributor shaft.
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Thursday, July 27th, 2017 AT 4:34 PM
Tiny
SOFTPICKLE
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Just an update, changed points, condenser, rotor cap and coil. I now have good spark. Now I am working on getting the fuel up to it. Appears my mechanical fuel pump maybe bad. Looking to switch it over to electric fuel pump with pressure regulator. What psi should the 2 barrel carb be set at?
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Friday, July 28th, 2017 AT 11:23 AM
Tiny
SOFTPICKLE
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Second question, the alternator I have only has one stud on the back of it and I am trying to figure out how to wire in a 4 wire voltage regulator. Any help as into how to wire it correctly would be appreciated.
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Friday, July 28th, 2017 AT 4:45 PM
Tiny
CJ MEDEVAC
  • MECHANIC
  • 11,004 POSTS
Don't let people make you think that an electric pump more advantageous.

IT'S NOT!

It actually will cause more problems and is more expensive.

A mechanical pump is a lot more reliable, and will put out plenty enough volume for you carb,

Before you go hog wild, see if your suction hose from the tank has a hole or split in it? Maybe the sock in the tank is stopped up? GOT GAS!

I have a 258 straight six cylinder. It now has an Offenhauser Intake and a Holley 390 4 barrel on it. My OEM pump delivers plenty of fuel to it!

What is the brand of the alternator?

Last pic is a "GM" alternator found on '76-'86 CJs, If this is what someone stuck on there, we can make it work, no need for a regulator, it's built in on these puppies.

The Medic
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Friday, July 28th, 2017 AT 6:05 PM
Tiny
SOFTPICKLE
  • MEMBER
  • 21 POSTS
My plan was to install an electric fuel pump and then put a pressure regulator between to pump and carb to bring the down the psi from 20 to 5.

I removed the mechanical fuel pump and blocked off one end then both ends with my hand and worked it but it would not bring any type of suction at all with either way. I figure that since it has sat for over a year and not ran, the diaphragm probably dry rotted. It looks like it could be the original pump that came with this engine.

I will take a pic of my alternator tomorrow and post it to see if you may see something I don't
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Friday, July 28th, 2017 AT 7:01 PM
Tiny
CJ MEDEVAC
  • MECHANIC
  • 11,004 POSTS
Looky here!

https://shop.advanceautoparts.com/p/carquest-mechanical-fuel-pump-6505/5403863-P?navigationPath=L1*14932%7CL2*14986%7CL3*15378

Ready to stick in.

2 bolts/ 1 screw in fuel fitting/ 1 hose clamp

Pressure is correct

Will shut off when the engine stops

Will not constantly pump fuel all over you when you have that 'possible accident'

No wires to come loose.

No regulator

No fuses

Normally an "On Hand" item at a parts store.

Lifetime warranty (buy it one time)

Heck, I guess mine have lasted 7-10 years on my past (6) CJ-5s, Four of 'em were daily drivers (never had anything else since I was allowed on the asphalt in 1981)

I can only suggest from my experiences, not trying to get you all roweled up!

CARADIODOC?

Your Opinion?

When you get the alternator info, I can probably get or make you a wire diagram to suit.

The Medic

(#1, #2, #5, #6 below and part of my man cave/ guest room)
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Friday, July 28th, 2017 AT 8:14 PM
Tiny
CARADIODOC
  • MECHANIC
  • 33,864 POSTS
The problem with the old set of points is they never brought the voltage down to 0 volts when you turned the crankshaft. No current ever flowed through the ignition coil's primary winding, so no electromagnetic field was produced. Those contacts were either badly pitted or arced, or they were misajusted to the point they never closed to turn on. Happy to hear that is solved.

For the generator, we need to know the model you have. AMC used a lot of Ford generators that used the four-wire voltage regulator. If you have a GM unit, the voltage regulator is built in. If someone put a Chrysler alternator on it, the job gets even simpler, but you'll want to use their two-wire electronic regulator. That applies if you have two separate plug-in field terminals on the back of the alternator. The '69 and older alternators used just one field terminal. You're better off installing the '70 and newer two-terminal alternator.
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Friday, July 28th, 2017 AT 8:16 PM
Tiny
SOFTPICKLE
  • MEMBER
  • 21 POSTS
No worries. Not roweled up at all. I just want to go the route of longevity. If the manual pump will work, I will go with it.
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Friday, July 28th, 2017 AT 8:29 PM
Tiny
SOFTPICKLE
  • MEMBER
  • 21 POSTS
Installed new mechanical fuel pump. Fired and ran as soon as the carb bowl was filled with gas. Thank you two for all your help and patience. Now I just have little things to do to get her back on the road.

Now that she runs, I can finally back her out of my garage so I can exchange a 4.0 in my friends tj. Hopefully this one will just be plug and play once everything is bolted up.
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Saturday, July 29th, 2017 AT 12:51 PM
Tiny
SOFTPICKLE
  • MEMBER
  • 21 POSTS
After getting it running, the alternator was showing 13.6v charging. I believe you are correct in it being a self contained regulated alternator
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Saturday, July 29th, 2017 AT 12:56 PM

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