Here's what I have. 97 XJ automatic with no start, not even hesitation to start.

- Engine cranks
- Fuel pump primes
- Fuel is present
- Relays and fuses are good
- No CEL
- New spark plugs
- New coil
- Swapped the Crank position sensor with a known good one (from a 2000 with manual trans, not sure if it makes a difference)
- Checked voltage at the plug into the coil, <1V on passenger side, 10V on driver side terminal on crank.

- Battery was kind of dead, but fairly new.

 

Has anything you listed above changed since the last time it started? If so what?

 

"not even hesitation to start" meaning nothing happens when you turn the key? If that's the case, try starting in neutral and wiggling the shifter to see if it's the NSS.

 

I know for sure the plugs are new. I can't verify how old the coil is, but it looks fairly new.

Meaning it's not stuttering to start. It cranks, but just cranks so I don't think it's the NSS. I've had that before and when it's the nss it won't usually crank.

 

White wire (passenger side) going in should be 12V I confirmed. Is this only with the key on run or all the time? Does anyone know where the white wire come from? Is it direct from the battery or does it go through somewhere else first?

 

test te coil by pulling a plug - hold it against a ground and have a friend crank it - should be a blue spark

 

Already tried that. No spark.

 

Have you measured the voltage going to the coil? - If no juse, check the fuse box - If all is well - then test the CPS

 

Did You run the coil tests on page 5-4, & 5-6 of the shop manual? Note that confirms that the roter and Cap as well. The CPS test is on page 6-20

 

Remove and clean grounds. Might help. Might not. But worth doing.



97-98

 

You may have a bad distributor or ECM failed not telling distributor to fire. The ECM failure is more common on XJ’s than we would like to think. Mine was rebuilt by the previous owner, I don’t know where he sent it for repair though but it is a possibility.

 

hi

It's possible that you have a defective distributor or that the ECM fails to notify the distributor to fire. The failure of the ECM on XJs is more prevalent than we would like to believe. My former owner rebuilt it; I'm not sure where he sent it for repairs, but it's a possibility. turkish citizenship

 

Ok...lol!
Lets start at the beginning...Lets make certain battery has a known good charge!!


1] What are the ground values (FB97XJ1 showed in the very nice images above)? ((((KEY OFF))))) DVM set to Ohms!
2] Clean all grounds that (FB97XJ1 showed in the very nice images above)
Do that first before even doing all the other stuff... because isn't nothing else gonna matter if you aint got the juice making it to the rest of the system.

 

I appreciate the help, but offering solutions without reading what was posted as known isn't helpful. The ECM is sending signal to the coil. I tested for voltage on start and ~10V is present. I posted above that the coil ISN'T receiving the 12V constant from the plug and am wondering if anyone knows where the 12V constant comes from. Whether directly from the battery or through some fused link/the ECM when the key is in the on/start position.

There's no CEL, the fuel pump primes, gauges all work, coil is receiving signal, and starter engages. If the 12V constant doesn't come from the ECM, it's unlikely the ECM would be bad with all of these things working as they should.

Where does this 12V constant wire come from?

 

The coil gets 12v from the ASD relay. The ASD relay is fed from fuse #18 (25a), and from the relay it goes to fuse 20 (20a), then goes to the coil through (according to the 1997 FSM) a dark green/orange wire. The gray wire goes back to the ECU, and it pulses ground to the coil.

The coil should have +12v key in run, and the ECU pulses ground to the coil. I like to use a logic probe to verify these, since it has a very high input impedance and doesn't draw current to light up.

XJJeeps.com has wiring diagrams.