Eagle_SX4

Those are the wires for the washer level sensor a feature not offered on the Comanche but was present on the Cherokees. Those wires are not attached to anything. The cabin side of the harness was never there.

It now runs. I don't know what fixed it but it runs. I reindexed the distributor and now it runs. I don't know what ended up being the issue. I think there were several things wrong all at once and I had to fix every one without knowing if it was fixed until everything was fixed together.

Checked for spark with a spark tester and I do have spark. But it still won't start. I have fuel at the rail but don't have a pressure gauge. VID_20250802_145344635~3.mp4 What is perplexing is that the rem still has the "CPS Crank fault" error. I am now going to pull my fuel pump and see if the hose has come undone.

I refreshed the grounds and it still won't start

@Ωhm just checked and the white with trace wire (D1) on the CPS connector is the sensor ground while the key is on. There is no connection to ground with the key off.

I am not getting any rpm reding on the REM or my tach.

I honestly don't know if my coil or ICM are good. That is something I can test but I don't have a spare to swap out. Test procedures for those would be much appreciated.

Thanks for the reply I am going to check all my grounds today and will report back.

Remove the distributor cap and either video the distributor or have someone watch it and make sure it is spinning while trying to start the engine. Like this. VID_20250801_183435337~2.mp4 I am still trying to figure this issue out myself. Even with my distributor my truck still won't start. I have tried 3 different new CPS sensors but it still won't start. I think I have the issue narrowed down to a bad ground. You can follow along in my thread here. I hope to get my truck running today.

To verify if C201_D1 is ground as shown in the 87 diagram it should be connected to either C201_B11 or C201_B12 with the ECU unplugged. I will test that theory tomorrow.

Looks like the ECU shares the ground with the fuel injectors, oxygen sensor and knock sensor. According to Cruiser54's notes it grounds at the engine block near the dipstick. I will clean and refresh that ground and the ground strap that goes to the body up by the wiper motor and maybe I will have a running truck again.

I don't think so I didn't have my wire diagram with me so I just tested all the pins at the computer connector to find which ones were connected to the CPS. Only one pin connected with each wire. C1 and D1. I found my wire diagram and found out the sensor is actually called the Engine Speed Sensor not the Crank Position sensor which I find odd. I will test tomorrow to see if the computer is grounding the white wire when cranking. Does any one know where the ECU ground is at? I can't find mention of it anywhere. Edit: found it on the diagram the ECU is grounded at G105. Where is that?

@NickInTimeFilms do you have any suggestions. Is there any reason other than a faulty CPS that the "CPS Crank fault" error would pop up on the R.E.M.?

I did check that and there is no connection between either wire and ground. And no connection from the CPS wires to ground.

Here is a very short video of it cranking just to show that the distributor is turning. VID_20250801_183435337~2.mp4

It is chewed a little bit but not enough to stop the new distributor from rotating. The REM has a sync readout with a rotating animation that is now turning but wasn't before I swapped the newly acquired distributor in.

I don't think the ECU is messed up because I have 2 of them and get the same rem code with both of them. My backup ECU was in my truck when I bought it and pulled it out when I found a 1990 manual transmission ECU in the junkyard. The 1990 ECU ran great until last week.

I just tried the 3rd new CPS and it still won't start. Measures .54 volts AC while cranking. I really need some help with this. REM still shows CPS Crank fault. I checked the continuity of the wires for the CPS to the computer and they were 0. Ohms so those are good. What else can I check?

Also if any one was wondering this is what the distributor gear looks like that got chewed up. I pulled it off and turned the old distributor into an oil pump primer.

Got another new CPS installed (NTK) and it still doesn't start. This one reads at .35 volts AC. I ordered 2 so tomorrow I will try the other one. Also checked compression on cylinder #3 it was 125. The sparkplug was wet with gas. Definitely not getting any spark.

According to rockauto the booster did not change from 84-91. I don't think you will have to do any mods on the fire wall to get the 95-96 booster to fit just make sure you have the spacer. I put a 97+ booster in my 87 and it fit fine but I had to shorten then weld the rod. Stick with the 95-96 booster and it will be easier.

I swapped in a newly acquired junkyard distributor just to see if I could get it running and it still won't start. I did properly index it after finding TDC. After not starting I tried rotating the distributor 180 degrees to see if I had TDC on the wrong stroke but it still didn't help so I switched it back to how it was when I indexed it. The rem still shows CPS Crank Fault. I double checked the CPS with my voltmeter and it says I am getting .57 volts AC. And about 215 ohms between the 2 wires on the CPS. I then checked for continuity on the CPS wires to the computer and both wires have 0 resistance between the engine bay plug and the computer plug. I then swapped the computer with a known good computer and the problem is still present. The CPS Crank Fault rem code keeps coming back when cranking. The next step is to order another CPS and see if a different one fixes my issue.

I just ran into this issue pull your distributor cap and make sure it is turning while the engine is being started. My camshaft ate my distributor gear and it was no longer spinning. The likelihood that your cam ate your distributor gear is very low but it can happen as I found out.

I don't know the cause of the issue. Based on how much oil is getting into my air filter I know my oil pump is functioning. However I haven't hooked up a mechanical oil pressure gauge to verify that the oil pressure gauge in my cluster is correct. The one in my cluster was showing about 45 psi cold and about 20 psi hot. But to test it I need to get another distributor.

Engine rebuild incoming. Read more here.