Putting the 99 back together, crank-no start

[sandyeggoxj]

99 xj, 4.0l, ax-15, 49-state SE
I parked the jeep in 2015 or so and I haven't ran the engine since. I pulled the battery at that time. Fuel pump went bad so I decided that it made sense to switch to a jaz fuel cell and return style fuel rail with all AN fittings. That project became a bigger project than I had time for and then the kids started coming. Same old story you've heard before.

I'm not 100% sure what I've done since it's been 10 years. I know I ripped out the airbox and built a new air intake. I replaced the clutch with luks parts. I finally got the fuel system done and running fine. I'm measuring around 45psi on the rail while cranking.

Cranks fine but no spark. I immediately replaced the CPS because its a jeep. That was a cheap part store version and it didn't fix the problem. So I replaced it again with a mopar CPS. I never really had the typical problems: never lost communication with PCM, gauges always worked normal, no DTC set.

I've tested sensor ground and 5V constant continuity to the CPS, TPS, IAC, MAP, CAM sensors from the PCM harness on connector A (A4 - ground, A8 - CPS signal, A17 - 5V supply). I tested the resistence of the CPS and I'm getting 4.42kOhm across pins 1 and 2 (sensor signal to sensor ground). I'm unclear if that is normal. Infinite resistance across sensor ground (pin 2) to 5v supply (pin 3)

The ASD relay tests fine and the fuel pump continues to run while I'm cranking. Swapped the ASD relay with another just to test. No change.

If I unplug the CPS nothing changes. I definitely have a damaged downstream o2 sensor from where it used to get slammed into the body when the exhaust would get smashed on rocks. I unplugged it just in case it was shorting to ground but that didn't change anything. Clutch switch functions correctly. Instrument cluster: volt meter is correct, fuel reads nothing because I don't have a fuel sender installed, oil pressure reads low (maxes out gauge if I unplug sensor), coolant temp reads out on my scan tool in the ball park temp I would expect for this time of year.

I have access to a 2006 4.0L TJ with manual trans that I could swap the PCM with if that is compatible. But I don't want to trash that one. I know the ignition is a little different on those. Any other suggestions? Should I try to get the PCM bench tested or repaired? Find a replacement to test? I don't want to throw money at it until I exhaust troubleshooting.

 

[sandyeggoxj]

I should add that I checked and cleaned the battery and block grounds as well as the misc grounds that are around the engine for all the random harness connections. All the fuses verify with a multimeter. The coil is also new because the old one was testing at the limits.

I'm trying to figure out if I missed something critical that is preventing the start and I don't realize it is missing.

 

[75SV1]

I had issues with the ignition switch electronic board. I used a Noid light to check if the injectors were getting power to them. I would crank, but no lighting of the Noid light, till I released the key. I mentioned it to a friend. He said it might be the ignition relay. I replaced it and it worked.

 

[sandyeggoxj]

Alright, Some updates! I picked up a Noid Test Light kit and I'm getting injector pulses. I'm measuring 45psi at the rail with a bosch 044 fuel pump so I am confident that I have good fuel. That should indicate that the PCM is seeing the output from the Cam Sensor correctly since it is pulsing the injectors.

I measured the ASD relay and I'm getting 12v across the coil pins during extended cranking so the ASD is not shutting off. I also tested the ASD relay and everything measures good on the relay. That means the CPS is working correctly and the PCM sees the crank turning?

 

[sandyeggoxj]

I had a helper for a little bit so I did some more testing. I have fixed something now because the PCM is actually sending a spark signal into the coil. Still not starting but my test light is lighting up at the coil signal connector. The coil is new but I'll look up the test procedure for the coil and see what I get.

I also noticed that my battery voltage is dropping more than I'd like during extended cranking. I have another battery that is in decent shape that I can swap in and see if that helps.

 

[75SV1]

Since your has a distributor, there is a Camshaft Position sensor in the Distributor. Also, check the distributor shaft. See if it can be pushed side to side. The spec is .001. Yeah, had that happed to me too. Also, I did have a coil go bad on one of my '98s.

 

[sandyeggoxj]

[SOLVED]
After fixing the initial problem of no spark with CPS I didn't notice that the injectors were junked up. The cranking sound was exactly the same. I cleaned out the old fuel and pulled the injectors and sprayed them out with brake cleaner. Back to running. Still running a little rough. Might look at some new injectors if it doesn't settle out after a tank of seafoam. It even starts up really nice for an ancient battery.

I've been out of the jeep world for a long time. What is cool and trendy for injectors these days?