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View Full Version : 93 zj 5.2 no spark...sometimes



4x4troy
06-28-2011, 11:09 AM
i just got a 93 larado 5.2 4x4.it runs good when it runs.sometimes it gets no spark.i pulled the power wire from the coil and its not getting power sometimes.when it gets power the auto shutdown relay clicks alot.and with a test light hooked to the coil pigtail the light gets brighter as the relay clicks then the clicking stops and the light goes out.then i can start it...sometime.but sometimes it still wont start.i have done the door lock thing..lock unlock...disco'd the battery and touched the ends together...replaced the coil...
i am lost and dont know what to do.could the ecm be bad? but remember it runs good when it does start up...its just hard to get it started.and it will only start after the relay does its little thing

Mudderoy
06-28-2011, 11:13 AM
i just got a 93 larado 5.2 4x4.it runs good when it runs.sometimes it gets no spark.i pulled the power wire from the coil and its not getting power sometimes.when it gets power the auto shutdown relay clicks alot.and with a test light hooked to the coil pigtail the light gets brighter as the relay clicks then the clicking stops and the light goes out.then i can start it...sometime.but sometimes it still wont start.i have done the door lock thing..lock unlock...disco'd the battery and touched the ends together...replaced the coil...
i am lost and dont know what to do.could the ecm be bad? but remember it runs good when it does start up...its just hard to get it started.and it will only start after the relay does its little thing

Hmmm I was going to suggest the CPS (but I don't know anything about this engine) but with that auto shutoff thingy, maybe not. It will be interesting reading about the solution.

4x4troy
06-28-2011, 12:09 PM
hey muddroy.i am think about replacing the cps i mean the worst that can is i have a new cps and a jeep that still does not run...lol.looks like i am going to be throwing parts at it.its got me confused

4x4troy
06-28-2011, 01:00 PM
now its not getting fuel...possible fuel pump...but with all this other stuff too...make any sence?

bigjim350
06-28-2011, 01:03 PM
does it have a factory or aftermarket security system? If so something from that could be shutting down fuel and spark

4x4troy
06-28-2011, 01:14 PM
yes it has the factory alarm

4x4troy
06-28-2011, 01:16 PM
i am thinking about replacing the ecu and the vtss mod.but the dash has to come apart for the vtss to be replaced/reset.

4x4troy
06-28-2011, 02:12 PM
could i swap my alarm ecu for a non-alarm ecu?i have ecu 56028011 with security...offered is a 56028011w/o security ecu also.could i just swap them out and fix my problem?

4.3LXJ
06-28-2011, 03:16 PM
I have heard of this kind of issue before with the factory alarm and auto shutdown. It can be reset at a dealership, sorry I don't know how to do it.

Mudderoy
06-28-2011, 03:27 PM
I have heard of this kind of issue before with the factory alarm and auto shutdown. It can be reset at a dealership, sorry I don't know how to do it.


Normally, putting the key in the drivers side door lock,
turning to the left, then to the right all the way
will unlock and disarm/reset the "OEM factory"
alarm system.

:link: (http://en.allexperts.com/q/Auto-Theft-Prevention-2384/2009/8/1995-Jeep-Grand-Cherokee.htm)

4x4troy
06-28-2011, 03:31 PM
Here is what is happening.

Jeep has very hard time starting, and currently will not start.

Vehicle - 93 Jeep Grand Cherokee Laredo 4x4 5.2

replaced coil
replaced auto shutdown relay
replaced battery
redid battery connection and verified all grounds to the engine
grounded out security system inside driver door

Here is what I was able to do until yesterday to get vehicle to start, once running it runs great, but
getting it started is getting worse and worse to accomplish.

1. Turn on Key
2. let sit for approx 30 seconds - security light comes on in dash (even after grounding out system)
3. let sit for approx 1-2 minutes - auto shutdown relay clicks rapidly for 3-5 seconds
4. check engine light comes on
5. able to start engine on first turn of key, catches immediately and runs great

Now - never get the rapid clicking in the auto shutdown relay, engine will not catch, cranks but will not
catch and start.
more...
i found some broke wires in the drivers door jam and hooked them back up.
now i get the rapid clicking again from the auto shutdown but it still wont start...and i can hear the fuel pump again.

4x4troy
07-02-2011, 08:51 PM
it is alive...put a new coil in and it runs...but it still will not start up until the asd relay does its thing then it will fire right up...and i thing the alternator is bad.

and i traded my ranger for a 97 jgc 4x4 4.0 tody...lol

4.3LXJ
07-02-2011, 09:31 PM
Glad to hear you are making progress.

4x4troy
10-25-2011, 06:41 PM
well its been fixed now for 2 months and doing great....but...it has gone under the knife. i will post up a link in the mod zj section.