Jeep Wrangler Forum - Reply to Topic
Jeep Wrangler Forum

Go Back   Jeep Wrangler Forum > YJ Jeep Wrangler Forum > YJ Tech Forum > 1991 YJ jeep wont start

Join Wrangler Forum Today

Thread: 1991 YJ jeep wont start Reply to Thread
Post Icons
You may choose an icon for your message from the following list:

Register Now

In order to be able to post messages on the Jeep Wrangler Forum 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 email address for yourself.
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.

Additional Options
Miscellaneous Options

Topic Review (Newest First)
04-24-2011 12:49 PM
Undead-89 I would see if you have voltage to the coil. there should be a DK GRN/BLK wire that runs from the the alt to the coil,Injectors, the ECM, the auto shutdown relay and the Heated O2 sensor. You can swap around relays to see if they make a difference if they are the same type. The good ones give you a picture on the side of what they do and if those match you are good to go.

Obviously the coil circuit itself is simple. the Wire from the alt comes in and the ECM acts as the ground telling it to turn on. You said the coil is god so either the wire in is bad, the wire to the ECM is bad or the ECM is not telling it what to do.

The ECM is new so for the sake of troubleshooting let's assume it is good, especially since it sounds like you got it to fix the problem. In that case something is telling it NOT to turn the Coil on. Of the thing that would probably tell it not to turn on the coil are. The Auto shutdown Relay, the Fuel system Relay, there is a another wire from the alternator that is TAN/BLK. I would make sure all of those are functioning or connected properly.

The IOD, if used in the same context as other places is the Ignition Off Draw. This is things like the Clock, the radio, alarm system and anything else that pulls current when the Jeep is off. Usually those pull milliamps so not enough to blow the fuse. When you say you have a short on those are you testing it, is it a diagnostic code or are you basing it on a blown fuse?
04-24-2011 10:46 AM
1991 YJ jeep wont start

1991 Jeep wrangler 6cylinder no power to coil, and 2 grounds, one on the fuel system ECU , and the other on the I.O.D, has a new fuel pump, new ECM, new speed sensor, new cam and crank sensors, I had the coil checked and its still good, I think the grounds are causing the auto shutdown relay to come on...It cranks but wont fire ..........Im about to light it on fire ....any opinions ? what is the IOD? could my new ECM be bad? Im stuck

Posting Rules
You may post new threads
You may 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

All times are GMT -5. The time now is 03:22 AM.

Jeep®, Wrangler, Liberty, Wagoneer, Cherokee, and Grand Cherokee are copyrighted and trademarked to Chrysler Motors LLC. is not in any way associated with the Chrysler Motors LLC