98 limited 4.0

had no spark after previously replacing cps and csps with cheaper sensors from rock auto. Put the new Napa sensors in and cleared previous p0340 code. Still no start but cranks strong. Hasn’t thrown annother code. Assuming still no spark. I’m lost on where to go from here. I’ve swapped the asd and fuel pump relays to no avail. All relevant fueses look good prior to Napa csps yesterday. Haven’t checked again. All other relevant data below

brand new battery and terminals
brand new crank and cam position sensors (Napa brand)
have fuel at rail ~48psi at pump prime
good continuity from csps signal and ground cavities to appropriate cavities on ecm
Cavity 1 on csps connector has 5v with key on
Battery to body ground is good
block to body ground good
rpm gauge doesn’t move while cranking
reverse lights work
jeep has been sitting for about two years

 

Check the grounds on the engine block itself, especially the one near the oil dipstick tube. Clean them until they're shiny metal. A no-spark, no-RPM signal on a 4.0 is almost always a bad ground killing the CPS signal, even with a new sensor.

 

Don't assume it doesn't have spark, confirm whether or not it has spark otherwise you're flying blind. I did this after leaving my jeep sitting for a few months and chased my tail on the ignition system only for it to fire right up when I stepped on the gas. The IAC had gotten stuck closed.

 

ok. Don’t know that I’ve seen that one. The one from the back of the intake manifold to the firewall is good if that’s what you’re referring to

 

I previously had no spark. Had no time to check again after installing new csps. Had to get to a concert. It’ll be the first thing I check next trip. Would a stuck iac cause no start even with starter fluid through the intake? I’m getting no sounds of combustion on crank

 

You test the ignition coil yet?

 

copy paste your original post into co-pilot or similar program

 

not yet. Didn’t have back probes or clips for my meter with me

 

im not familiar. Could you give me more info