92 Jeep YJ No Spark at Plugs - JeepForum.com
Search  
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 JeepForum.com > Models > Jeep Wrangler Forums > YJ Wrangler Technical Forum > 92 Jeep YJ No Spark at Plugs

Savvy Billet LED Tail LightsLight up the holidays with LED lights from JeepHutIntroducing MONSTALINER™ UV Permanent DIY Roll On Bed Line

Reply
Unread 11-20-2014, 02:25 PM   #1
johnnyj4811
Registered User
 
Join Date: Nov 2014
Location: Corbin City, NJ
Posts: 6
92 Jeep YJ No Spark at Plugs

Whats going on jeepforum, I have a 92 Jeep YJ 4.0 manual that I cant seem to get started.

I have two issues...

First I am getting no spark to the spark plugs to ignite the cylinders, however I am getting spark out of the coil. So far I have replaced my cap and rotor, plugs and wires, coil, crank sensor, battery, alternator and ECU. Still no spark to the spark plugs.

Second My also brand new fuel pump will not engage due to the fact only 6-8volts are coming from the connector and the fuel pump requires 12volts to run.

Please help, I have been trying to get her running for weeks.

johnnyj4811 is offline   Reply With Quote Quick reply to this message
Unread 11-20-2014, 03:03 PM   #2
mike134
Registered User
1989 YJ Wrangler 
 
Join Date: Aug 2014
Location: Cleveland, OH
Posts: 1,307
Sounds frustrating, better stop throwing parts at it, or its going to get expensive!

First, does your check engine light come on when you turn the key to the ON position? This is a very important symptom for 91-95 model years.

Any check engine codes?
mike134 is offline   Reply With Quote Quick reply to this message
Unread 11-21-2014, 12:37 PM   #3
johnnyj4811
Registered User
 
Join Date: Nov 2014
Location: Corbin City, NJ
Posts: 6
Yes very frustrating, I guess it comes with the territory lol. But when the key is in the on position only the seat belt light comes on for all of two seconds then goes away.
johnnyj4811 is offline   Reply With Quote Quick reply to this message
Unread 11-21-2014, 01:31 PM   #4
mike134
Registered User
1989 YJ Wrangler 
 
Join Date: Aug 2014
Location: Cleveland, OH
Posts: 1,307
ok, in a 92, no check engine light when the key is turned to ON means that the capacitors in your engine computer are bad. I see that you swapped the ECU already. was that NOS or was it from a junkyard?

You need to follow this thread: http://www.jeepforum.com/forum/f12/c...rs-ecu-492597/

The electrolytic material inside the capacitors dries out after 20 years or so and they need to be replaced. It costs about 50 cents if you know how to solder. If you don't know how to solder, bring it to a friend or learn this very useful skill.

If you have an old stereo, television, computer monitor, ham radio, They can often be repaired in the same way. One of the very first things to try is replacing all of the old electrolytic capacitors.
mike134 is offline   Reply With Quote Quick reply to this message
Unread 11-21-2014, 03:14 PM   #5
johnnyj4811
Registered User
 
Join Date: Nov 2014
Location: Corbin City, NJ
Posts: 6
I bought the computer online from rock auto, its refurbished. My old computer wouldn't even produce spark to at the coil. Is there a chance this new computer could be defective still?
johnnyj4811 is offline   Reply With Quote Quick reply to this message
Unread 11-21-2014, 03:35 PM   #6
mike134
Registered User
1989 YJ Wrangler 
 
Join Date: Aug 2014
Location: Cleveland, OH
Posts: 1,307
its possible the caps are bad. The hotter the capacitor the shorter its service life. So running the computer and the engine makes the electrolytic material expire faster. However, it will go bad eventually without being used anyway.

It follows a curve like the one at the bottom of this post, where heavy use brings failure towards "Practical Life Expectancy". However, we are unfortunately going past "average life expectancy" now. If your caps made it past the hump, expect failure soon..

You may want to ensure that your check engine light bulb isn't burned out though. Its rare, but a possibility.

mike134 is offline   Reply With Quote Quick reply to this message
Unread 11-21-2014, 03:52 PM   #7
johnnyj4811
Registered User
 
Join Date: Nov 2014
Location: Corbin City, NJ
Posts: 6
I could solder new capacitors in but I will return my new ECU if thats the case because I still have my core. I will check the lightbulb tomorrow just to make sure...also I was reading that no spark at the plugs could be the cam sensor or the distributor assembly, could this be a possibility also? I really don't want to keep throwing money at this thing I just want to go wheeling.
johnnyj4811 is offline   Reply With Quote Quick reply to this message
Unread 11-21-2014, 04:00 PM   #8
mike134
Registered User
1989 YJ Wrangler 
 
Join Date: Aug 2014
Location: Cleveland, OH
Posts: 1,307
Yeah, get the money back for the ECU you just bought. Solder the capacitors into the old one. These computers are pretty rugged and almost always repairable. The three capacitors will cost about 50 cents.

the cam sensor can cause this problem if your vehicle has one.

Before doing more sensors, I would reinstall the old computer and see if the no CEL symptom still occurs. If no CEL, change the caps.

You could have a problem in addition to the capacitor issue. To find out, you can charge the computer up and try to start the vehicle before doing your cap swap. Grab your favorite magazine and turn the ignition to ON. Wait 15 minutes (use magazine here). If the computer fires up in 15 minutes you will hear a relay kick on and the CEL should come on to indicate the computer is ready. You can then turn the vehicle on.
mike134 is offline   Reply With Quote Quick reply to this message
Unread 11-21-2014, 06:56 PM   #9
johnnyj4811
Registered User
 
Join Date: Nov 2014
Location: Corbin City, NJ
Posts: 6
Ok, I really appreciate the help btw! This is my first thread on JEEPForum and so far its been awesome! Tomorrow, Im gonna start on the things we discussed and ill check back in.
johnnyj4811 is offline   Reply With Quote Quick reply to this message
Unread 11-21-2014, 08:25 PM   #10
laybackman
Bikini Bridge Inspector
 
laybackman's Avatar
1995 YJ Wrangler 
 
Join Date: Dec 2002
Location: Massachusetts
Posts: 6,292
Turn your ignition switch to the ON position and wait......until the CEL lights up. If it does the engine will then fire and run. You have bad caps in the ECM.
__________________
"Taking care of our veterans is a cost of war. If you can spend six trillion dollars sending people to war, you can spend a few billion dollars taking care of them when they come home"
Sen. Bernie Sanders (I-Vt.)

If what doesn't kill you, makes you stronger, I should be able to bench press a Grand Cherokee by now!
laybackman is online now   Reply With Quote Quick reply to this message
Unread 11-22-2014, 12:25 PM   #11
johnnyj4811
Registered User
 
Join Date: Nov 2014
Location: Corbin City, NJ
Posts: 6
Ok, to not overlook any possibilities, I checked the light bulb of the check engine light and it is fine. I even switched my seatbelt lightbulb with the check engine lightbulb to make sure. I also checked all fuses and they all look fine. Listening to Mike I set the key to the on position and let it sit for 15-20 minutes. After this, I checked for any codes and the check engine light still did not illuminate. My friend has a YJ as well I am going to start by switching his computer into mine and see if it makes a difference.

My question now is, could it be possible that anything else besides a bad ECU/ECM would cause no check engine light illumination. Or could it be possible that everything is good but maybe there is a loose or broken wire somewhere else or maybe corrosion I cant see inside the fuse box? I've searched for any wires in poor condition but they all look in good shape.
johnnyj4811 is offline   Reply With Quote Quick reply to this message
Unread 11-22-2014, 02:47 PM   #12
mike134
Registered User
1989 YJ Wrangler 
 
Join Date: Aug 2014
Location: Cleveland, OH
Posts: 1,307
There could be a problem in addition to the bad capacitors, but you have the classic bad cap symptoms so at the very least that needs to be addressed.

You could try waiting longer than 15 minutes since it is cold out. 15 usually does it though. The CEL has to come on before the engine will start.
mike134 is offline   Reply With Quote Quick reply to this message
Unread 11-22-2014, 03:47 PM   #13
laybackman
Bikini Bridge Inspector
 
laybackman's Avatar
1995 YJ Wrangler 
 
Join Date: Dec 2002
Location: Massachusetts
Posts: 6,292
Quote:
Originally Posted by johnnyj4811 View Post
Ok, to not overlook any possibilities, I checked the light bulb of the check engine light and it is fine. I even switched my seatbelt lightbulb with the check engine lightbulb to make sure. I also checked all fuses and they all look fine. Listening to Mike I set the key to the on position and let it sit for 15-20 minutes. After this, I checked for any codes and the check engine light still did not illuminate. My friend has a YJ as well I am going to start by switching his computer into mine and see if it makes a difference.

My question now is, could it be possible that anything else besides a bad ECU/ECM would cause no check engine light illumination. Or could it be possible that everything is good but maybe there is a loose or broken wire somewhere else or maybe corrosion I cant see inside the fuse box? I've searched for any wires in poor condition but they all look in good shape.
Check EVERY fuse in your PDC under the hood and under the dash board. I mean pull each one and test it for continuity with a multimeter
__________________
"Taking care of our veterans is a cost of war. If you can spend six trillion dollars sending people to war, you can spend a few billion dollars taking care of them when they come home"
Sen. Bernie Sanders (I-Vt.)

If what doesn't kill you, makes you stronger, I should be able to bench press a Grand Cherokee by now!
laybackman is online now   Reply With Quote Quick reply to this message
Unread 11-22-2014, 04:24 PM   #14
Mark05059
Registered User
1989 YJ Wrangler 
 
Join Date: Mar 2009
Location: quechee Vermont
Posts: 4,379
especially the dome fuse
__________________
1998 ZJ 5.2 Auto

1989 Wrangler Black Bone Stock 2.5l 5spd
/l , [____],
|---L--[]lllllll[]-
()_) ()_)==O=)_)
Mark05059 is online now   Reply With Quote Quick reply to this message
Reply

Quick Reply
Message:
Options

Register Now

In order to be able to post messages on the JeepForum.com forums, you must first register.
Please enter your desired user name, your email address and other required details in the form below.
User Name:
Password
Please enter a password for your user account. Note that passwords are case-sensitive.
Password:
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:

Log-in

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






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