Your Not Gunna Believe This One!!! - Off-Road Forums & Discussion Groups
Jeep-Short Wheelbase All discussion of short wheelbase Jeeps: CJ, TJ, YJ and JK

 
LinkBack Thread Tools Display Modes
post #1 of (permalink) Old 08-04-2001, 01:15 AM
**DONOTDELETE**
Guest
 
Posts: n/a
Your Not Gunna Believe This One!!!

Ok......I have a 1989 4.2 YJ (Carb)5 spd...Durning the past week or so i have been having a hell of a time trying to pin point a problem with the ignition. I have resently replaced Cap , rotor, plugs, battery, and ECU and also had the ignition module tested( and it tested good). The YJ turns over but dosnt Fire, It has Spark to the plugs,and Fuel. After i installed the ECU i was planning on test all the wires for a spark. And thats when i stumbled apon this !!! I had my ignition key turned to the "ON" postition( not the crank)and a spark plug grounded to the frame to test it.....so i attached my negative post on the battery and noticed a spark coming from the plug....Keep in mind that the jeep's ignition has not been cranked over.........so i disconnected the neg cable ...and the sparked stopped......touched it again...and low and behold there's the arc again.......I guess this is the reason why my YJ hasnt been able to start.........Please I need some advice. What would cause this????????....thanks for taking the time to help.
Bern

Sponsored Links
Advertisement
 
post #2 of (permalink) Old 08-04-2001, 01:51 AM
Way Outta Control
 
Join Date: Sep 1999
Location: The Palouse
Posts: 13,432
Thanks: 1
Thanked 3 Times in 3 Posts
 
Re: Your Not Gunna Believe This One!!!

You may want to re-test. What you describe can happen if the correct set of circumstances are in occurance:

1. Ignition set to RUN mode and the engines stopped at about 8* BTDC of the compression stroke for the plug that's pulled.
2. Rotor pointing to the distributor tower of the pulled spark plug.
3. Hall effect swtich in position to pulse the ignition module.

So now you remove the ground wire for the battery and replace it.

4. The ignition circuit doesn't care where the battery cable is.
5. The ignition circuit sees that power has been restored. Just like turning the igniton to RUN mode.
6. The hall effect switch recieves power and sends a pulse...
7. To the ignition module which sets up a pulse to...
8. Pulse the coil. The coil being pulsed reaches saturation....
9. And builds up voltage which is sent via the distributor cap to the...
10. Spark plug and the voltage jumps the gap...
11. And you have ONE spark occur.

Now, move the engine by hand 10 degrees or 20 degrees CW and repeat the procedure...

You should not see the spark occur. If you do... somethings really messed up, likely in the distributor.

LEVE is offline  
post #3 of (permalink) Old 08-04-2001, 09:09 AM
Keyboard Implanted
 
TOM85CJ7's Avatar
 
Join Date: Sep 1999
Location: Austin, Texas
Posts: 2,072
Thanks: 0
Thanked 0 Times in 0 Posts
 
Re: Your Not Gunna Believe This One!!!

How did you get your ignition module tested? Where?

Thanks,


http://home.off-road.com/~tom85cj7/home.htm
TOM85CJ7 is offline  
Sponsored Links
Advertisement
 
post #4 of (permalink) Old 08-04-2001, 09:13 AM
Can't Get Enough
 
z50k2's Avatar
 
Join Date: Feb 2000
Location: Charleston, SC
Posts: 1,483
Thanks: 0
Thanked 0 Times in 0 Posts
 
Re: Your Not Gunna Believe This One!!!

Advance Auto checks modules. They have a machine with all of the adapters. Tell them it is for a Ford.
Ricky...seeya...

CJ-7 with LOTS O' CRAP
http://hometown.aol.com/ericselz/myh...e/profile.html
z50k2 is offline  
post #5 of (permalink) Old 08-04-2001, 12:15 PM
**DONOTDELETE**
Guest
 
Posts: n/a
Re: Your Not Gunna Believe This One!!!

Got the module tested at Napa, and for good measure i also took it to AutoZone it tested good at both locations

post #6 of (permalink) Old 08-04-2001, 12:46 PM
**DONOTDELETE**
Guest
 
Posts: n/a
Re: Your Not Gunna Believe This One!!!

Thanks Leve......The spark did not accur angain.......Damn and i thought i was on to ssomething....Guess iam just reaching for [censored]. This damn Jeep got me sracthing my heaD.


post #7 of (permalink) Old 08-05-2001, 03:04 PM
**DONOTDELETE**
Guest
 
Posts: n/a
Re: Your Not Gunna Believe This One!!!

You can't test a module!
Module usally come and go, work and don't work.
Most of the time when they fail is do to HEAT. They can't test it for that.
I had a bad module in my 87. Every other day it would stall and when I started it (if it started) it would back fire. I had my Module test at AutoZone, they said it was good. My old man and his friends said "you can't test a module"
So I bought a new one for 60 dollars (because there wasn't anything left that could be wrong) and it fixed it. For 4 years so far!

Rob
http://sites.netscape.net/tapboxerc/homepage
Sponsored Links
Advertisement
 
Reply

Quick Reply
Message:
Options

Register Now



In order to be able to post messages on the Off-Road Forums & Discussion Groups 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 email address for yourself.

Email Address:
OR

Log-in










Thread Tools
Show Printable Version Show Printable Version
Email this Page Email this Page
Display Modes
Linear Mode Linear Mode



Posting Rules  
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On

 
For the best viewing experience please update your browser to Google Chrome