Electrical Puzzle need HELP - JeepForum.com
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post #1 of 8 Old 11-08-2017, 08:02 PM Thread Starter
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Electrical Puzzle need HELP

Been trying to figure this thing out on my own and by looking through other posts, which have been extremely helpful in steering me in the right direction so far.
Any help would be greatly appreciated!

Before it totally stopped running, it would sometimes die on me after running for awhile. I would pull in and park somewhere, come back and back out and it would struggle to go. Then it would die as I tried to get from 1st to 2nd. (Automatic) It would make this clicking/popping noise at the gas pedal that you could feel and sometimes it would catch and then run fine in higher gears, but sometimes it wouldn't and slowly bog out and die. This problem started happening more and more frequently until it finally decided to not start at all. And so it sits.

It died a handful of times this way during normal driving. I would wait 15 minutes - 2 hours and then I could get it to start, barely. And I just basically kept driving on it because it would seem fine for awhile...

Here’s where I’m at now:

1997 Jeep Cherokee Sport
4.0 6cylinder
260k miles

Won’t start, but cranks.
No pressure in fuel rail.
No spark at plugs.
Fuel gauge doesn’t work.
Fuel pump doesn’t come on.

No power at certain fuses in Power Distribution Center under the hood (fuses look fine):
10 - Automatic Shutdown Engine Controller
11 - Automatic Shutdown, Oxygen Sensor

No power at certain fuses inside passenger side:
3 - Left Headlight High Beam
4 - Left Headlight Low Beam
5 - Right Headlight Low Beam
6 - Instrument Panel Dimmer
7 - Left Parking Light
14 - Heated Mirrors
16 - Right Headlight High Beam
19 - Start Relay *****Hmmm***
23 - Right Parking Light

I found 2 loose/cut wires on the Downstream O2 sensor, so I replaced the sensor.
Makes sense because It was giving me a Oxygen sensor code earlier when it still ran… Check engine light not on now.

Replaced Fuel Pump Relay and ASD relay.

When I unplug the Crankshaft Position Sensor (CPS) under the hood, then the fuel gauge works.
Turn key on and you can hear fuel pump!
10 PSI in fuel rail when key on, and same when cranking.

I held in odometer and the dash display did the 'diagnostic' thing, if that helps.

Recently replaced starter before she stopped working.
Battery seems good.

Worth mentioning maybe: The plug to what I think is the AC system on the passenger side near fuses is melted/fried.
This may or may not be related. AC cold and fan settings 1-3 haven’t worked since I’ve had it. Fan setting 4 works.

What would you do?

Last edited by benjamminson; 11-08-2017 at 08:36 PM. Reason: added backstory
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post #2 of 8 Old 11-09-2017, 01:01 PM
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2014 JK Wrangler 
Join Date: Oct 2017
Posts: 7,591
Tell us is jeep STOCK, anything electrical modified, added changed ANYTHING?

BS like alarms, remote starters, audio, again ANYTHING.

could you confirm this PDC fuse #s
(fuses look fine):
10 - Automatic Shutdown Engine Controller
11 - Automatic Shutdown, Oxygen Sensor

My diagram does not agree SO I will accesss jeep and see what is OEM and PDC circuits,
SO far sounds a PDC issue
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post #3 of 8 Old 11-09-2017, 01:36 PM
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Is this your PDC ?

And if so id the fuses with issues
Attached Files
File Type: pdf jeepxjPDC.pdf (30.1 KB, 7 views)
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post #4 of 8 Old 11-09-2017, 09:07 PM Thread Starter
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Location: Richmond
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OH weird, I was going by Jeep Manual. I've been having this confusion while reading on forums...

My relays are set up different than that image, but the F24 and F21 spots are the ones with no power

The Jeep is stock.
It did have an aftermarket cd player, which stopped working and was removed. Could loose wires in there really cause a problem like this?

Last edited by benjamminson; 11-09-2017 at 09:18 PM.
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post #5 of 8 Old 11-09-2017, 09:10 PM Thread Starter
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I think 2 through 15 were fine, but let me double check
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post #6 of 8 Old 11-11-2017, 08:10 PM
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Not sure if it'll help.... but here's the jeep spark map that i grabbed off one of the forums awhile back for myself to see how jeep wired their start-up.

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

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post #7 of 8 Old 12-01-2017, 10:11 PM
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Considering that some things started working again after you unplugged the CPS, along with some of the other symptoms you described, you may have a bad CPS. If a CPS shorts, it can, and often will, lock up the ECM. The fact that the fuel gauge and pump started working after you unplugged it is a pretty good sign that it may be bad, as the ECM controls both on your XJ. This would also prevent spark, as the ECM controls the spark, and was locked up by the CPS. Without the CPS, the ECM doesn't know when to fire the plugs, so you will still get no spark. You may have additional problems, but that would be a good place to start. Of course, I wouldn't just change out the CPS without testing it first. I'm not a big fan of throwing money at a problem until it goes away.

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post #8 of 8 Old 12-01-2017, 11:21 PM
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I'd focus on the no crank first. That said, your symptoms match those of a bad Crankshaft Position Sensor (CKP). My grandson's 2001 Cherokee Sport had the same symptoms, and replacing the CKP solved it. I used a MOPAR CKP based on the many posting recommending them on this forum. If you haven't replace a CKP before, I strongly remommend viewing all of the Youtube videos for this. Also, if your CKP has two bolts, I recommend you take out the top bolt first; and, during the install put the bottom bolt in first. That way there's less chance of dropping a bolt into the CKP's hole.

2001 Cherokee Sport
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asd , cps , o2 sensor

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