No Spark and out of ideas, please help! -
Sign Up   Today's Posts
User: Pass: Remember?
Advertise Here
Jeep Home Jeep Forum Jeep Classifieds Jeep Registry JeepSpace Jeep Reviews Jeep Gallery Jeep Clubs Jeep Groups Jeep Videos Jeep Events Jeep Articles
Go Back > Models > Jeep CJ Forum > No Spark and out of ideas, please help!

Introducing MONSTALINER™ UV Permanent DIY Roll On Bed LineAwesome Open box items at OPENBOXOFFROAD.COMJeep parts, deals and more at

Unread 04-08-2012, 06:37 PM   #1
Registered User
Join Date: Mar 2012
Location: Minneapolis, Minnesota
Posts: 1
No Spark and out of ideas, please help!

Hello, I'm a novice to auto repair and I've tried everything I can think of to get my CJ7 started, and am out of ideas. Its an 86 CJ7, 4.2L. I've replaced the solenoid, starter, ignition module, ignition coil, plugs/wires, distributor, distributor cap/rotor, and the battery. Its turning over, but I'm not getting any spark. Not sure what else I can try replacing. Any of your thoughts or ideas would be greatly appreciated!

1986 CJ7, not a daily driver, yet...
MarcF1977 is offline   Reply With Quote Quick reply to this message
Unread 04-08-2012, 06:39 PM   #2
Registered User
2005 TJ Wrangler 
Join Date: Mar 2012
Location: vincennes, IN
Posts: 143
Have you check to see if your coil is getting power? maybe either way there will help you know if it's before or after that. maybe help
clydegoat is offline   Reply With Quote Quick reply to this message
Unread 04-08-2012, 06:41 PM   #3
Registered User
1983 CJ7 
Join Date: Aug 2004
Location: [duhm-as]
Posts: 4,512
Check the ecm fuse.
I bought a super clean all original CJ7 for dirt cheap because it didn't run.
The owner took it to three shops which they could not find the problem.
They also replaced every part like you did.
A 20 cent fuse and I was cruising.
I think it was a 3amp fuse labeled lights or cluster.
LT1CJ7 is offline   Reply With Quote Quick reply to this message
Unread 04-08-2012, 06:56 PM   #4
Web Wheeler
pman's Avatar
1988 YJ Wrangler 
Join Date: Aug 2005
Location: Charleston, SC
Posts: 1,348
I once had a similar issue on my Wagoneer...ended up being the ignition switch located midway down the steering column under the dash. It would crank, but I wasn't getting fire.
88 Wrangler Laredo 258-999-NP231
81/76 CJ5 304-t150-Spicer 20
82 Wagoneer 360-727-NP208
82 CJ8 Scrambler 258-t5-Dana 300
pman is offline   Reply With Quote Quick reply to this message
Unread 04-08-2012, 09:46 PM   #5
Web Wheeler
BagusJeep's Avatar
1981 CJ7 
Join Date: Jul 2009
Location: Bali, Indonesia
Posts: 4,837

You are doing what a lot of us do, replacing bits without finding the problem. In a 25 year old CJ this is at best replacing bits before they fail, at worst introducing further issues. Find the problem first.

Thought No. 2 - BUY SOME TEST GEAR

Simple stuff on a CJ. A 12V test light, not LED, which you can make out of old junk or buy for $5, will allow you to test the low voltage side. A multimeter is useful but not AS USEFUL.

Thought No. 3 - TEST IT
If you dig up Jeephammer's old posts you will find a number of simple test procedures that will pinpint which part of your system is not working. Be methodical and you will find the root cause.

__________________________________________________ ______________________________________

Having said all that, here is what I would do. I followed JH's test routines and discovered a short at the ICM plug. Yours will no doubt be different.

If you want a simple test hook that lamp up between the red with tracer wire at the coil (disconnect it first) and the -ve terminal on the battery. A dim bulb in Run, a bright one in Start. That confirms you have coil voltage. If you do not then you have a wiring problem smewhere, see below diagram.

Hook the lamp between the +ve battery terminal and the green wire from the coil. When you try and start it should blink, that confirms you have a ground signal from the ICU in time with the engine. If you do then the pckup in the distributor, ICU and computer are working.

If those check out it is the coil or the distributor.

Put the wires back on the coil. Take the lead from the centre of the distributor, connect it to an old spark plug and rest it on the cylinder head. In Start you should get a healthy blue spark and snap.

If so then look at the distributor. Take any lead you like and repeat the spark plug test.

By this time you should have isolated the problem to one specific area. Report back and we can look closer at that area.

It should take less than 5 minutes to do that testing.

If your ignition is standard here is a simple diagram of the wiring that may be of help. Yours is slightly different as it has a feedback loop from the ICM to a computer that is itself wired to the fusebox. The fuse referred to above is the IGN LPS fuse, worth checking as that pesky computer will stop the rest of it from working IF you do not have a signal on that green wire.
BagusJeep lives in Bali, the Land of Temples.
With a Jeep every prayer counts.

1981 CJ7 258ci - Bagusjeep
1984 CJ7 258ci - Puthijeep
1981 J20 258ci - Gladys
1995 Cherokee 4.0 - CHEROKEE
BagusJeep is offline   Reply With Quote Quick reply to this message

spark , starter

Quick Reply

Register Now

In order to be able to post messages on the forums, you must first register.
Please enter your desired user name, your email address and other required details in the form below.
User Name:
Please enter a password for your user account. Note that passwords are case-sensitive.
Confirm Password:
Email Address
Please enter a valid e-mail address for yourself.
Note: All free e-mails have been banned due to mis-use. (Yahoo, Gmail, Hotmail, etc.)
Don't have a non-free e-mail address? Click here for a solution: Manual Account Creation
Email Address:


Human Verification

In order to verify that you are a human and not a spam bot, please enter the answer into the following box below based on the instructions contained in the graphic.

Thread Tools

Suggested Threads

Jeep, Wrangler, Cherokee, Grand Cherokee, and other models are copyrighted and trademarked to Jeep/Chrysler Corporation. is not in any way associated with Jeep or the Chrysler Corp.