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  #1  
Old March 14th, 2018, 07:37
rc10t4orange rc10t4orange is offline
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Crank but no start. I can hear the fuel pump running.

So my 01 XJ started acting kinda funny. Hiccuped and died a couple times restarted ok. Now all I get is cranking but it wont start. I can hear the fuel pump running and I made sure there was plenty of gas in it. I'm leaning towards crank or cam position sensor? Maybe coil pack? What would I test first? Is there a write up on this? Thanks in advance.
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  #2  
Old March 14th, 2018, 07:51
RCP Phx RCP Phx is offline
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Re: Crank but no start. I can hear the fuel pump running.

You need a scanner to tell what's not functioning right.
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  #3  
Old March 14th, 2018, 07:57
rc10t4orange rc10t4orange is offline
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Re: Crank but no start. I can hear the fuel pump running.

I assume it's npt just a regular code scanner you are talking about?
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  #4  
Old March 14th, 2018, 07:59
RCP Phx RCP Phx is offline
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Re: Crank but no start. I can hear the fuel pump running.

Anything that reads/reports OBD codes.
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  #5  
Old March 14th, 2018, 08:02
rc10t4orange rc10t4orange is offline
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Re: Crank but no start. I can hear the fuel pump running.

Ok thanks. When it was running there were no service engine lights on. I know that doesn't mean anything though. Thanks for the input. I'll hook it up to a scanner tonight.
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  #6  
Old March 14th, 2018, 08:10
Heavyopp Heavyopp is offline
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Re: Crank but no start. I can hear the fuel pump running.

Buy/rent/borrow a fuel pressure gauge -- hook it up right at the fuel rail -- your 2001 should have 48 pounds of fuel pressure at the rail with the key on

If you do not have pressure then it's most likely your fuel pump -- If you do have pressure then I would look at the Crank position sensor

I am not sure if there is a way to check the crank position sensor -- You should have the coil rail so it's not easy to pull a plug and check for spark but you should check for spark

Had this happen on my 2000 just a month ago -- ran, stalled, started, ran, stalled started -- got it home -- never started again -- I had fuel pressure at 42 pounds, and was stalling on me at left turns if I had less than 1/4 tank of fuel -- A sign of clogged fuel filters in the tank -- So I swapped in a bosch fuel pump assembly, pressure washed the inside of the tank, reinforced the inner frame rails with 3/16 plate, and chassis savered the entire back end while the tank was out

Put it all back together, jeep started right up -- Next day, no start -- same thing just crank -- I had swapped out my coil rail for the viper coil so it was easy to check for spark -- No spark -- checked the ASD relay -- that was good so I swapped Crank Position sensor -- All good fired right up and been good ever since -- I do need to get another CPS in my possession to have as a backup

Last edited by Heavyopp; March 14th, 2018 at 08:56.
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  #7  
Old March 14th, 2018, 08:20
Heavyopp Heavyopp is offline
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Re: Crank but no start. I can hear the fuel pump running.

Quote:
Originally Posted by RCP Phx View Post
Anything that reads/reports OBD codes.
What is his test procedure -- assume no CEL - no codes present

Does the scanner help after that?

I couldn't get anything irregular on the scanner when mine died -- I will admit I'm new actually owning a scanner -- Maybe I just don't know how to use/read it
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Old March 14th, 2018, 08:31
rc10t4orange rc10t4orange is offline
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Re: Crank but no start. I can hear the fuel pump running.

Heavyopp thanks for the help. You confirmed my thoughts. Sounds like we had the exact same symptoms.
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  #9  
Old March 14th, 2018, 09:02
Heavyopp Heavyopp is offline
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Re: Crank but no start. I can hear the fuel pump running.

I agree, we had the same symptoms -- I hate to just throw parts at a problem hoping to get it right but I don't think there is a decent test for a CPS -- it's such a common issue

Took me maybe 30 minutes to change and I had never done it before -- not terribly hard to access from the bottom -- I did happen to have a "parts XJ" around so I didn't buy a new sensor -- I will buy one now to have a spare on hand
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  #10  
Old March 14th, 2018, 09:26
RCP Phx RCP Phx is offline
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Re: Crank but no start. I can hear the fuel pump running.

Quote:
Originally Posted by Heavyopp View Post
What is his test procedure -- assume no CEL - no codes present

Does the scanner help after that?

I couldn't get anything irregular on the scanner when mine died -- I will admit I'm new actually owning a scanner -- Maybe I just don't know how to use/read it
You don't always get a CEL when codes are present! Unfortunately fuel pressure isn't monitored but it's easily checked!
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Old March 14th, 2018, 10:02
rc10t4orange rc10t4orange is offline
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Re: Crank but no start. I can hear the fuel pump running.

Quote:
Originally Posted by RCP Phx View Post
You don't always get a CEL when codes are present! Unfortunately fuel pressure isn't monitored but it's easily checked!
Thank you sir. Just got a code scanner at lunch. Used one several times but never had my own. Will definitely check CEL the fuel pressure. If I have no codes and fuel pressure probably just replace crank position sensor.
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Old March 14th, 2018, 10:03
rc10t4orange rc10t4orange is offline
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Re: Crank but no start. I can hear the fuel pump running.

Meant to say "check CEL then check fuel pressure"
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  #13  
Old March 14th, 2018, 10:35
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Tim_MN Tim_MN is offline
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Re: Crank but no start. I can hear the fuel pump running.

Test the CPS.

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.

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

Begin with 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 or connectors and replace as needed. Do the same for the grounding wires from the starter to engine block, and from the battery and engine to the Jeep's frame/body. Jeeps do not tolerate low voltage or poor grounds and the ECM/ECU may behave oddly until you remedy this.

Symptoms –
- Starter cranks and cranks but engine won't start up and run.
- Fuel gauge and voltage gauge may not work or display properly.
- You sometimes will have No Bus on the odometer after 30-60 seconds.
- A failed CPS/CKP may or may not throw a CEL trouble code.
- No spark at the spark plugs.
- 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 ECU/computer or cannot read Check Engine Light/MIL codes because the CPS/CKP has failed. Disconnect the code reader, disconnect the CPS/CKP wire connector, and reconnect the code reader. If the code reader establishes contact with the ECU and scans, your CPS/CKP is failed and needs to be replaced.

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 and/or the No-Bus is gone, replace the CPS.
- 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 the relays as the cause of the no-start. Check the ASD relay fuse.
- Confirm that the fuel pump to 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 exhausts pipe. A short circuit from melted insulation or from broken O2 sensor wires can blow a fuse and the ECU/ECM will loose communication. Don’t get tunnel vision and assume the sensor is bad (unless it tests bad with a meter). Damaged wiring or a dirty connector can inhibit the signal from making it to the computer. Inspect/test/clean/repair wiring or connectors as necessary.

CPS Testing

Crankshaft Position Sensor Connector (CPS/CKP)
.

.
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 (See Image). Ohmmeter should be set to 1K-to-1OK scale for this test.
3. The meter reading should be open (infinite resistance). Replace sensor if a low resistance is indicated.

TESTING PROCECURE for 1987 – 1990 4.0 L engines

Test # 1 - Get a volt/ohm meter 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 .5vac, replace it.


The 2000 and 2001 will have the CPS in the same location on the bell housing, but the wire connector may be on the passenger side, not as shown in the diagram below. Simply follow the wire from the sensor to the connector.

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  #14  
Old March 14th, 2018, 10:43
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Coach Bruce Coach Bruce is offline
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Re: Crank but no start. I can hear the fuel pump running.

Every 4.0 owner should have a spare CPS on board so don't be afraid to get one and if that's not the problem you will now have your spare. It is unlikely the coil pack but stranger things have happened.

You can cheek that you at least have fuel pressure by releasing pressure at the fuel rail Schrader valve. It is not going to tell you if you have the right pressure but will let you know if you at least have some.

Good luck.
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  #15  
Old March 15th, 2018, 06:00
rc10t4orange rc10t4orange is offline
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Re: Crank but no start. I can hear the fuel pump running.

Didn't have much time last night. I plugged in the scanner and it said P0340 camshaft sensor. Now it's got me puzzled?
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