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-   -   1996 Cherokee - New Starter, Won't start? (http://www.jeepforum.com/forum/f11/1996-cherokee-new-starter-wont-start-1361087/)

TheJBJester 04-25-2012 09:53 AM

1996 Cherokee - New Starter, Won't start?
 
Chucked a new Bosch Starter in for my sister because the old one went, obviously. It has been running great for a few weeks now, and suddenly it will not start... It turns over fine, but will not fire. I am not sure if the problem is related.

I suppose it could be a number of things, but if any one out there has a solution because maybe it's a common problem?

Thank you in advance!

chriskeenan 04-25-2012 09:59 AM

CPS maybe

93zjer 04-25-2012 12:09 PM

Crankshaft post sensor would be most common. You can try replacing the most likely components or you can actually troubleshoot the problem properly.

Check for pressure at the fuel rail while starting.
-The fuel pump should run for a few seconds when the key is turned to ON.
-Turn key to ON,
-Press the valve on the fuel rail to release the pressure.
-Next, If you don't have a fuel pressure gauge just have someone try starting the jeep while you press the valve on the rail.
-Gas should gush out as long as the key is held in the START position.

If you have fuel pressure begin testing for spark.

If the fuel pump does not cycle when the key is held to START check for voltage at the pump while starting.
If voltage is present but pump does not run, replace the fuel pump.

If there is no voltage to the fuel pump or if you are not sure how to test for spark come back here.

TheJBJester 04-25-2012 09:06 PM

I really appreciate it guys. Although, I have some new intel:

I went there today to check it out. At first, it would simply turn over and not fire. Then, it spontaniously fired. At first it was idling like crap, almost as if timing was out. Then it started idling fine. So I shut it off, and started it again. It proceeded to idle perfectly.. So I shut it off, and started it again. Again it idled like crap, and then fine again.

Would those symptoms be consistent with CPS failure? If so, I will run the tests.

Thank you very much gentlemen.

93zjer 04-26-2012 01:40 AM

Its hard to say, the CPS could fail intermittently, could be fuel supply or MAP sensor, Worn cap/rotor many things really. I had a fuel pump fail in my last 93 ZJ that gave symptoms like this. Had to use a fuel pressure gauge to see that my fuel pressure was not being consistently maintained.

If this is on your 96 XJ, you can start by getting a code reader for OBD2 and see if the problem has thrown any codes. Most likely you would have a check engine light though if it had.
You can also check the cap and rotor for excessive wear and check the distributor shaft for excessive play, I've seen them wear out and make 4.0's run funny.

After that you might have to get down to real troubleshooting which means test for fuel while cranking (might want a fuel pressure gauge) or do like I said in the above post redneck style.
If you have fuel (rail maintains pressure and injectors fire), test for spark.
If you have good spark, test for compression.

Some guys get lucky throwing parts at problems, in my experience you end up spending less time, money and frustration if you methodically follow a logical troubleshooting procedure.


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