Today while driving to work, my cherokee just cut off. RPM to Zero, no power steering, the works. After pulling over, I found it will crank, but won't start.

Since I work at a garage, and I was going to work, I had it towed there. The lead mechanic said after some testing that it was probly my Crankshaft position sensor, which I agreed. I got one, slapped it in there, and still no start. But on the good note, on a lift, Replacing that sensor is easy as ****.

After my own testing, I have fuel pressure, which if it was the CSPS I'd have no pressure.

Any ideas? It's at the shop now, and I'm at home, so I can't do anything right now, but ideas for tomorrow are helpful.

I'm learning towards it being the ignition coil, I replaced my factory one with an Accel one, and I found out later they tend to randomly die. But through text, the lead mechanic says maybe my Dist is bad. Which is annoying to even talk about.

 

I could agree with the coil being worth replacing. Pull the distributor cap and check the rotor and contacts.

 

Check all the fuses? I had this symptom on a customers XJ once. Has fuel, no spark, no injector pulse, replaced CPS and nothing. I found a popped fuse under the hood. Put a new one in and it popped again.. I checked the wiring harness around the intake and header and found a O2 sensor wire melted and grounded to the #1 exhaust tube behind the P/S pump.
Only seen it happen once but you never know cause that is a pretty crappy place to put wires.

 

Omg!

 

Actually we checked all fuses too. That would be an awesome simple fix. Strange how your wires melted though.



OMG! Indeed

 

I have seen this several times myself, worth looking into lads

 

I had the same problem. No spark. I ended up changing the dis cap the rotor and the camshaft sensor which is the disc below the rotor. It started right up after changing those 3 things

 

Did you try starting fluid through the intake to see if that would start it? and do you have spark?(I'm assuming you checked being at a garage..)If it starts with the starting fluid, but dies when you let off the trottle cable, replace your coolant temp senser. I've dealt with this a couple times now. I replaced every sensor under the hood, along with all the stuff for fuel and firing. and it was this stupid sensor... so glad I'm going back to a renix!.. lol

 

Lol..Now I see in your thread name, no spark.. nevermind.

 

You'll still have fuel pressure, the pump runs for about 5 sec when you turn the key to pressurize the system, CPS or not.
Do you still have the factory coil you removed? If so, swap it back in and see what you get.

 

Certainly test your ignition coil next. It isn't difficult; you test for both primary and secondary resistances. You'll need a meter and a manual outlining the specs. I am NOT a fan of either Accel or MSD coils. In my experience, they have a short service life and don't give you any real advantage over an OEM style coil for a stock 4.0 engine.
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Spark: 12 volts from ignition switch to the ASD relay; when the key is first turned on the PCM provides a ground to the ASD relay to energize it, then the ASD relay passes 12 volts to the coil primary side. If no crank sensor signal is generated after a couple of seconds the PCM cuts the ground to the ASD relay (and fuel pump relay too) and that cuts power to the coil (and fuel pump). Key to START and once again the PCM energizes the ASD relay. Now, a critical element is the crank sensor--no signal from the crank sensor and the PCM won't trigger the coil to provide spark.

 

Coolant temp sensor?! What does that have to do with no start?

Just lick your finger, stick it in the top of the coil and turn the key on.

 

I had an Accel coil on my jeep for about a year went out on lunch from work and had the same issue..fuel but no spark....I figured the same thing as you and changed the CPS...still no spark so I took my stock coil and threw that on their and it fired right up...not saying that the coil is your issue but I have read the same thing as you that the Accel coils dont last at all

 

I know when my CPS went out the coil was out also. I don't know if it is possible for the cps to take out the coil or if the coil can take out the cps. But I have seen on several occasions that when one goes the other goes. Don't know why but it happens.

 

Somehow, it messes with the other sensors that send fuel to the injectors. You have the pressure at the rail, spark, and it will roll over, but no go!
Like I said, I replaced EVEYTHING.. and a buddy of my dad, who specializes in cherokees told me to replace it to begin with. I told him he was crazy. hundreds of dollars later, it was the cheapest sensor under the hood.