It's been a minute since I was last here, need some help with a non-start issue - JeepForum.com
 1Likes
  • 1 Post By CJ7-Tim
 
LinkBack Thread Tools
post #1 of 9 Old 02-24-2020, 08:21 PM Thread Starter
Walton99
Registered User
 
Walton99's Avatar
 
Join Date: Feb 2004
Posts: 562
It's been a minute since I was last here, need some help with a non-start issue

Howdy yall! It's been a while since I've been around but I once again need the knowledge this place contains.


My old '01 XJ won't start.


A little while ago I had just replaced the steering box and was letting the jeep idle in the driveway to work all the bubbles out of the PS system and she just died, no sputter, no warning, nothing.


Now when I try to start her she cranks fine, and will start to catch but will backfire through the intake and just won't start.


Any and all assistance / ideas would be much appreciated. Thanks in advance.


'01 XJ
Hp44, Ford 9", 37" MTR's, 5.13's
Quote:
Originally Posted by Helicop
a true "pandora's box" of off-road machinery.
Gig'em Aggies
Walton99 is offline  
Sponsored Links
Advertisement
 
post #2 of 9 Old 02-24-2020, 08:56 PM
Pinoy59
Registered User
1997 XJ Cherokee 
 
Join Date: Apr 2015
Location: Globe
Posts: 120
Garage
I would check for spark first. Could be something like the CPS, or coil, or fuel pump.
I recently had a short on an o2 sensor that was blowing a fuse every time i turned it over. You never know what it could be. Basically check for spark and fuel first

Sent from my SM-G975U using Tapatalk

NP242/skidplates/RC4.5"LA kit/33x12.5mudclaws/15x10rim/sliders&flares/trussed-locked8.8/winchbumper
Pinoy59 is offline  
post #3 of 9 Old 02-25-2020, 04:35 AM
CJ7-Tim
Real Jeeps have dents
 
CJ7-Tim's Avatar
2000 XJ Cherokee 
 
Join Date: Apr 2002
Location: out in the garage - Minneapolis
Posts: 27,906
A faulty Crankshaft Position Sensor is the first thing to suspect when there is random stalling and/or the starter is cranking but the engine not starting. Test the CPS.

Test the fuel pressure. Check for spark.



The most likely cause of it cranks and cranks but won't start up is the Crankshaft Position Sensor (CPS) located on the transmission bell housing. Often this part is also referred to as the CranKshaft Position Sensor (CKP). CPS/CKP failure is very common. The CPS/CKP can stop working with no warning or symptoms and the engine will not run or the engine may randomly stall for no apparent reason. Typical CPS lifespan is about 150-200,000 miles.

Crank Position Sensors can have intermittent “thermal failure”. This means that the CPS/CKP fails when the engine gets hot, but works again when it cools back down.


Symptoms-
- Starter cranks and cranks, but engine won't start up
- Fuel gauge and voltage gauges may not work or display properly.
- You sometimes will have NoBus displayed on the odometer after 30-60 seconds.
- A failed CPS/CKP may or may not throw a CEL trouble code.
- No spark at the sparkplugs.
- Fuel pump should run and prime for 3-5 seconds.

If the CPS/CKP is failed sometimes the OBD-II trouble code reader cannot make a connection to the computer or cannot read Check Engine Light/MIL codes because the CPS/CKP has failed.

Diagnostic steps to confirm the CPS is the cause of your no-start:
- You should be able to verify a bad CPS, by unplugging it, and turning the ignition key to ON. If the voltage gauge and/or the fuel gauge now displays correctly, replace the CPS.
- Check the orange wire going to the CPS or cam position sensor for 5 volts with the key in the run position. A partial short in a sensor can cause the input voltage to the CPS (or most sensors) to be low and can trigger a no-start or no bus situation.
- Unplugging and reconnecting the CPS sensor where it connect to the main harness near the back of the intake manifold usually resets the ECU and if the jeep fires right up after doing this you can bet that the CPS is faulty and needs to be replaced.
- Exchange the fuel pump relay and the ASD relay with one of the other similar ones in the PDC to eliminate these relays as the cause of the no-start. Confirm that the fuel pump runs for 3-5 seconds when you turn the ignition key to ON.
- Eliminate the NSS as a cause of no start. Wiggle the shift lever at the same time you try to start. Put the transmission in Neutral and do the same. Do the reverse lights come on when the shifter is in Reverse ?
- Inspect the wires and wire connectors at the O2 sensors on the exhaust pipe. A short circuit from melted insulation or from broken O2 sensor wires can blow a fuse and the ECU/ECM will lose communication.

If you buy a new CPS, get a genuine Jeep CPS. Cheap crappy “Lifetime Warranty” parts are often out of specification or even failed right out of the box. They usually also have a shorter service life than better quality parts. Buy good quality repair parts and genuine Jeep sensors for best results.

You must also perform basic trouble shooting of the start and charge systems. Remove, clean, and firmly reconnect all the wires and cables to the battery, starter, and alternator. Look for corroded or damaged cables and replace as needed. Do the same for the grounding wires from the battery and engine to the Cherokee's frame/body. Jeeps do not tolerate low voltage or poor grounds and the ECM/ECU will behave oddly until you remedy this.

Crankshaft Position Sensor Connector(CPS/CKP)
.







.









CPS Testing


TESTING PROCEDURE 1991 –2001 4.0L H.O. engines
1. Near the rear of intake manifold, disconnect sensor pigtail harness connector from main wiring harness.
2. Place an ohmmeter across terminals B and C or 2 and 3 (See Images). Ohmmeter should be set to the 10K-or-2OK scale for this test.
3. The meter reading should be open (infinite resistance). Replace sensor if a low resistance is indicated.

TESTING PROCEDURE for 1987–1990 4.0 L engines
Test # 1 - Get a volt/ohmmeter and set it to read 0 - 500 ohms. Unplug the CPS and measure across the CPS connector's A & B leads. Your meter should show a CPS resistance of between 125 - 275 ohms. If the CPS is out of that range by much, replace it.
Test # 2 - You'll need a helper for this one. Set the volt/ohm meter to read 0 - 5 AC volts or the closest AC Volts scale your meter has to this range. Measure across the CPS leads for voltage generated as your helper cranks the engine. ( The engine can't fire up without the CPS connected but watch for moving parts just the same ! ) The meter should show .5 - .8 VAC when cranking. (That's between 1/2 and 1 volt AC.) If it's below .5 VAC, replace it.

The 2000 and 2001 will have the CPS in the same location on the bell housing, but the wire connector is on the passenger side, near or on top of the Transfer case, not as shown in the diagram below. Simply follow the wire from the sensor to the wire connector.
.


jtec likes this.

.
“When the people find that they can vote themselves money, that will herald the end of the Republic.”

- Benjamin Franklin
CJ7-Tim is offline  
 
post #4 of 9 Old 02-25-2020, 05:07 AM
jtec
Web Wheeler
 
jtec's Avatar
2014 JK Wrangler 
 
Join Date: Oct 2017
Posts: 7,557
have you looked at anything?
the sputtering and BACKFIRE would have me look at-
when cranking do injectors pulse?
is there fuel pressure?
Check for codes?...... simple easy.
Inspect 'read' a spark plug or 2.

When I see the price of OEM I think aftermarket.
When I see the quality of aftermarket I think OEM.
jtec is online now  
post #5 of 9 Old 02-25-2020, 12:37 PM Thread Starter
Walton99
Registered User
 
Walton99's Avatar
 
Join Date: Feb 2004
Posts: 562
I appreciate all the help guys. The first thing I did was replace the CPS with a mopar one I had sitting on the shelf, they're a pain in the butt and I know they're finicky, but I'll throw a multimeter on there and see if the new one is within specs.

Plugs are new champion truck plugs.

My thoughts on the spark and fuel was that if the motor wasn't getting either then there wouldn't be any backfiring or even attempts to start. But I'll go back through and check for both.

I appreciate all the help, thank you.
Walton99 is offline  
post #6 of 9 Old 02-25-2020, 01:40 PM
jtec
Web Wheeler
 
jtec's Avatar
2014 JK Wrangler 
 
Join Date: Oct 2017
Posts: 7,557
what is a champion 'truck spark plug' ?
IIRC should be using RC12ECC, a simple solid core type plug.

Did you try for codes ?

When I see the price of OEM I think aftermarket.
When I see the quality of aftermarket I think OEM.
jtec is online now  
post #7 of 9 Old 03-03-2020, 07:31 AM Thread Starter
Walton99
Registered User
 
Walton99's Avatar
 
Join Date: Feb 2004
Posts: 562
Alright, quick update.


It ended up being a bad CPS. The old one didn't pass the test in the FSM so I installed a new one and she fired right up. Thanks for all the help guys, I appreciate it.

'01 XJ
Hp44, Ford 9", 37" MTR's, 5.13's
Quote:
Originally Posted by Helicop
a true "pandora's box" of off-road machinery.
Gig'em Aggies
Walton99 is offline  
post #8 of 9 Old 03-03-2020, 08:27 AM
TheBoogieman
Disturbed Jeepaholic
 
TheBoogieman's Avatar
2003 TJ Wrangler 
 
Join Date: Aug 2006
Location: charlottesHELL
Posts: 39,788
Quote:
Originally Posted by Walton99 View Post
Alright, quick update.


It ended up being a bad CPS. The old one didn't pass the test in the FSM so I installed a new one and she fired right up. Thanks for all the help guys, I appreciate it.
Aren't you glad you came back?

Quote:
Originally Posted by jeepinmichguy_ View Post
TheBoogieman is a jerk.
03' Rubicon/Zone 4" coils with 1" spacers up front/Rancho shocks/5.13 gears-35" MTZs/Black Magic brakes. SOLD for Covid-19 pandemic rent money. :(
99' XJ /4.0L-AW4/ 5.5" lift / Rancho shocks/33" DC Extreme country MTs. Jeep #18
TheBoogieman is online now  
post #9 of 9 Old 03-03-2020, 12:56 PM Thread Starter
Walton99
Registered User
 
Walton99's Avatar
 
Join Date: Feb 2004
Posts: 562
Quote:
Originally Posted by TheBoogieman View Post
Aren't you glad you came back?

absolutely

'01 XJ
Hp44, Ford 9", 37" MTR's, 5.13's
Quote:
Originally Posted by Helicop
a true "pandora's box" of off-road machinery.
Gig'em Aggies
Walton99 is offline  
Reply

Quick Reply
Message:
Options

Register Now



In order to be able to post messages on the JeepForum.com forums, you must first register.
Please enter your desired user name, your email address and other required details in the form below.

User Name:
Password
Please enter a password for your user account. Note that passwords are case-sensitive.

Password:


Confirm Password:
Email Address
Please enter a valid e-mail address for yourself.



Email Address:
OR

Log-in











Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
 
Thread Tools
Show Printable Version Show Printable Version
Email this Page Email this Page



Posting Rules  
You may post new threads
You may post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are On
Refbacks are On

 
For the best viewing experience please update your browser to Google Chrome