Need the best "no start" brains

[hotrodbuilder]

I have a 1993 wrangler, 4cyl, manual, 140K. Jeep was sitting for 3 years. I put in a new battery turned the key and no spark, no fuel pressure, no 3 second prime. I do have a "check engine" light. From reading in this forum, I have checked the fuses, relays, wiring harness, grounds etc. All looks good and this jeep is really clean for its age. If I ground the ASD relay I get voltage to the coil and the fuel pump works. After finding no cause for the condition I have, I replaced the computer and guess what. Same problems!!!! Any ideas? Any schematics online? Could it be a bad ignition switch? Could the CPS cause all these problems even against the belief of the people that replied to my last post? Please save this jeep from an early death.

 

[joe_peters]

Check your grounds, in particular the grounds for the PCM. The PCM provides the ground to the ASD relay and cuts it after 3 seconds or so if no signal is received from the CPS/CKP.

CPS/CKP, ASD relay, PCM, and grounds are what I would suspect for your symptoms.

You said with the ASD relay ground provided the pump ran and you got power to the coil--but did you get spark?

 

[hotrodbuilder]

I cleand all the ground connections and found no issues. Do you know what pin on the pcm connector is the ground referance? I have 12 volts at the coil when the ASD relay is grounded but I have no pulse signal for spark. Thanks for the help.

 

[jeeperz]

Your grounds seem to be good, but here are pin outs for 2.5L 4cyl. For a 92 but should be the same for 93.
pin#
4 sensor ground
5 ground for fuel
11 ground
12 ground
32 check engine lamp
57 Z2 sense

You say you have voltage to the coil, but no spark.Check cap and rotor, plug wires, spark plugs, coil wire, to eliminate any bad connections. Also pull the harness plug and check terminals for corrosion at the cps plug. May be failed coil, they have a high failier rate. So a new coil may be needed, or crank positioning sensor is fualty/bad may need replacing.

 

[kastein]

Did it crank? You didn't say that... I'm guessing it does.

 

[hotrodbuilder]

Yes, the jeep turns over fine. When I jump the ASD relay it gives my 12 volts at the coil, however I do not have any spark coming out of the coil and I do not detect any pulse to fire the coil. I will check the pins at the pcm and see if I have a broken wire. Thanks again for the help.

 

[joe_peters]

Yes, the jeep turns over fine. When I jump the ASD relay it gives my 12 volts at the coil, however I do not have any spark coming out of the coil and I do not detect any pulse to fire the coil. I will check the pins at the pcm and see if I have a broken wire. Thanks again for the help.

Well, sounds like CPS/CKP crank sensor, harness, or ECU/PCM then.

Good luck, don't forget to post back what you find.