93 zj 5.2 no spark...sometimes

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Jun 27, 2011 | 09:45 PM
  #1  
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
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Jun 27, 2011 | 10:34 PM
  #2  
Do you have a factory alarm?

Lots have issues with them.
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Jun 27, 2011 | 10:56 PM
  #3  
Could be a cam or crank sensor.
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Jun 28, 2011 | 10:56 AM
  #4  
ye i do have the factoru alarm..its not the cam or crank sensor....the relay does crazy stuff and then sometimes it will crank.and sometime i got to lock unlock the doors and it will fire up.i am thinking it is the factory alarm...how can i bypass it?
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Jun 28, 2011 | 11:06 AM
  #5  
Quote: ye i do have the factoru alarm..its not the cam or crank sensor....the relay does crazy stuff and then sometimes it will crank.and sometime i got to lock unlock the doors and it will fire up.i am thinking it is the factory alarm...how can i bypass it?
Search. Again, lots have had issues with them.

Sorry, I'm not a GC guru.
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Jun 28, 2011 | 11:11 AM
  #6  
i have searched and have not found an answer thats why i made this tread.and the ones i have found with somewhat of an answer just leaves you hanging on if that was really the problem.
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Jun 28, 2011 | 01:08 PM
  #7  
now no fuel?????????????????????????????????
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Jun 28, 2011 | 02:19 PM
  #8  
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?
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Jun 28, 2011 | 03:21 PM
  #9  
better explanation..

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.
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Jun 28, 2011 | 03:23 PM
  #10  
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.
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Jun 28, 2011 | 04:09 PM
  #11  
I had this problem it ended up being the fuel pump. If the pump doesn't build pressure fast enough it will trigger the auto shutdown system. I replaced the computer,camshart censor crankshaft censor,fuel pressure regulator and battery. Still had the problem fuel pump fixed it.

Good luck.
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Jun 29, 2011 | 04:14 PM
  #12  
well i need to test the pressure at the rail.
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Jun 29, 2011 | 07:04 PM
  #13  
I'm not sure what the pressure needs to be but check it with the motor running to.
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Jun 29, 2011 | 08:17 PM
  #14  
can't get the motor running...no fire
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Jul 2, 2011 | 08:50 PM
  #15  
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
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