[TRA1216]

I have a 2000 Jeep Cherokee Sport (2 wheel drive) that is now refusing to start. Have replaced fuel pump and filters, had carbon cleaning treatments, replaced all battery cables and connections, and replaced crank shaft sensor. About one month ago I was told by an auto shop that the fuel pump was going bad but i had plenty of time. One and a half weeks ago the Jeep stopped starting. The motor cranks but does not turn over. Had a friend that is a mechanic replace the fuel pump and the filter. The Jeep still will not start. He was able to get the fuel pump to pump the fuel to the engine, but the injectors would not work. Towed the Jeep back to the auto repair shop when after 3 days they diagnosed the problem as being a bad sensor in the pcm computer and the computer needs to be replaced. Being as i have already paid for several repairs (this same issue has been "fixed" several times since February), and a new air conditioning condenser unit, i am weary to put another $800 if this is not the problem. Any thoughts on this?

[eflores]

chryco computers are way tough. are you sure your injectors arent firing? checked them with noid light? what about spark are you getting spark?

[wil badger]

Could be a series of things.

Cam position sensor ( not to be confused with the crank position sensor)
Throttle position sensor
Coil pack has gone bad or is going bad

I'm sure if a sat here long enough I could come up with a few more but those are the main ones that come to mind.The things I listed can be checked for the most part.

[collkid]

Did you check to see if you have a spark when turning?

Fuel
Spark
Air

[TRA1216]

It does have spark when turning. It works long enough to burn off starter fluid if sprayed into the throttle body. The auto repair shop I took it to had run it through all of the diagnostics and then had to take off each sensor individually to test them. My friend was able to get the fuel to pump to the injectors, but the injectors did nothing. As I am sure you can imagine i am very frustrated with this Jeep, although not quite ready to give up yet. : ) Thanks for all of your quick responses!

[1offroadin4x4]

I'd be willing to bet on the computer if it has spark. While I was hauling groceries home a couple years back my 01 cherokee decided to start missing out really bad, engine light came on, and it stopped dead in its tracks and wouldn't start up. Diagnosis......needed new main computer, it had burnt out. 400.00 dollars later it was purring like a kitten again. You can always pull the injectors and hit em w/ a 12v battery to see if they are working. You should be able to see the hole in the tip open and shut and here a click when power is applied.

[ksmanimal]

Kinda makes one long for the days of carburetors and point ignition, huh?

[xjarchaeologist]

My bet is computer. This happened on my friend's ZJ and we pulled a compy from a junkyard and fixed it. Maybe it'll be that easy for you? I hope so...Good luck!

[oldmanriver]

I'm not sure if it's just a lost in translation thing but the computer doesnt really "have" sensors, it just reads information provided by sensors and sends commands. So if it's a sensor they should replace it, not the computer.

If you havent gotten a second opinion I would, unless you know the people working on your jeep. Never know when a dealer is blowing smoke up your ***, and they tend to try it on women more.

Just want to make sure your covering all your bases, $800 is a big chunk of change...

Good luck

[CJ7-Tim]

Get a second opion from an independent repair shop.

If the starter engages and the motor turns over, but will not run, and you have fuel but have no spark, look at and test the Crank Position Sensor.


The most likely cause of it cranks and cranks but won't start up is the Crank Position Sensor (CPS). CPS failure is very common. The CPS can stop working with no warning or symptoms and the motor will not run.

Symptoms -

Fuel gauge and voltage gauges may not work or display properly.

You sometime will have No Bus on the odometer after 30-60 seconds.

NO spark.

Fuel pressure OK

If the CPS has failed sometimes the OBDII code reader cannot make a connection to the computer or cannot read Check Engine Light/MIL codes because the CPS has failed.


Diagnostic steps to confirm the CPS is the cause of your no-start

You might 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.

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.

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?

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 and replace as needed. Do the same for the grounding wires from the battery and engine to the Cherokee's frame/body.

CPS Testing


Crankshaft Position Sensor Connector







NOTE: To perform a complete test of the Crankshaft Position (CKP) sensor and its circuitry, refer to the appropriate Power train Diagnostic Chart. To test the sensor only, refer to the following:

PROCEDURE
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.

[TRA1216]

Thanks for all of the replies. I am going to try your suggestions and see what happen. And yes, from what i hear, I do wish for carburetors again. : )

[Jeep gal]

And have the battery checked. Another gal here that went through starting problems....it cranked fine. But the battery was bad. Replaced it and haven't had a problem since.

[perrysjeep 98]

My 1998 did the same thing and after the dealer took 4 days, the proublem was the crank position sensor.

[Matt Gertsch]

Another cam sensor vote. Without signal from the cam sensor, the ECU won't fire the injectors.

[eflores]

yup cam sensor is my vote