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No Spark

A

AirForce_XJ

NAXJA Forum User
Location
Raeford, NC (Fort Bragg)
No spark and plugs or coil. Going to grab a new CPS today anything else that might cause this? Already checked the FAQ just asking the peanut gallery for any opinion. '89 4.0 AX-15 NP231, didnt have the issue till i dropped the tranny to change the clutch. I am getting ready to Move back to germany and need to sell the Heep but kinda hard to do if its a paper weight.
 
You wouldn't be the first to bugger the CPS/CKP while pulling a transmission. Did you try plugging/unplugging it a few times?
 
Yeah. Tried unplugging the battery fully as well. Now my battery is dead, got a bad cell in it. I had a horrible rear main seal leak not to long ago and didnt clean it off very well, so i am pretty sure that didnt help the CKP much. :doh:
 
Replace the battery first, before changing the CPS/CKP.

Renix has to "crank up" to 300 rpm before the CPS/CKP signal will be strong enough to get the ECU to trigger spark.

With a bad cell you might not have 9+ volts during cranking, and less than 9 volts the electronics are not going to work.
 
Well, changed the battery, still nostart but a solid crank now. So the CKP is gettin swapped tomorrow.Will update the status after i get that done and ask for more advice if i need it.:repair:
 
Last edited:
B.RAIDER said:
Do a search for the B latch relay.
Click to expand...

Good call.

Is the fuel pump priming for 3 seconds when you turn the key to the ON position??

Check the grounds at the dipstick tube, they are critical to the Renix.
 
hmm when my ballast resister went i had no spark either.. i also thought it was my CKP sensor. replaced that and nothing. replaced the Ballist resistor and boom. but i dont know. u seem like u know a lot more bout jeeps than i do. im just a honda mechanic lol with the love of jeeps and finally out of the whole lets make cars fast scene.
 
Shred Bro Gnar Rad said:
hmm when my ballast resister went i had no spark either.. i also thought it was my CKP sensor. replaced that and nothing. replaced the Ballist resistor and boom. but i dont know. u seem like u know a lot more bout jeeps than i do. im just a honda mechanic lol with the love of jeeps and finally out of the whole lets make cars fast scene.
Click to expand...

Well, you made a good call on the B Latch relay. I got tunnel vision when he said no problem until the trans work, and then I focused on the CPS/CKP.

The ballast resistor only comes into play when the engine is running, and it is receiving 12v from the fuel pump relay and then reduces that to about 6v to the fuel pump.

When the key is turned to ON the B latch relay provides a direct 12v to the fuel pump bypassing the ballast resistor then if the ECU doesn't receive a signal from the CPS/CKP the ecu kills the power.

When in the START position the starter relay provides 12v direct to the fuel pump, again bypassing the ballast resistor.

When at WOT the oxygen heater relay provides 12v direct to the fuel pump, once again bypassing the ballast resistor.
 
Changed a all my relays and the CKP as well as the battery terminal connections and she fires right up. So the problem lay in there somewhere. Thanks for the help guys!!:repair:
 
AirForce_XJ said:
Changed a all my relays and the CKP as well as the battery terminal connections and she fires right up. So the problem lay in there somewhere. Thanks for the help guys!!:repair:
Click to expand...

:party:
 
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