Fuel or ignition problem?

[midnight special]

So I have an 88 GC 4.0L with 227,312 miles on her. It will not start, but will turn over fine, there is fuel in the rail and the proper fuel pressure, but dry plugs. I think it maybe the camshaft positioning sensor but am unsure. If anyone has some advice I would appreciate it, I'm at that point where I just start throwing parts at her and hope one takes.

 

[MudderChuck]

The crank position sensor (CPS)( on the bell housing) called by other names is the most likely candidate. If the computer detects no pulse from the CPS, it will not spark or cycle the injectors. Which Cherokee do you have an XJ or ZJ? I'm guessing an 88 XJ, the test for the CPS is an ohm test 200 ohms plus or minus 75. The wiring for the CPS has also been known to cook on the exhaust manifold and the connector to get oxidized and cause poor contact.
You can have the proper fuel pressure because the fuel rail primes for a second or two as soon as the key is turned to run on the way to start.
The cam position sensor (in the distributor) really doesn't do much in the pre 90 XJ's and other than mechanical damage and shorting on occasion or developing an internal short, is unlikely to cause much noticeable grief. A short in the cam position sensor can cause problems in other sensors becuase it shares a 5 volt supply/reference voltage with other sensors.
The nomenclature in the XJ gets a bit confusing, various manuals and even the FSM and OEM parts catalog sometimes use a different name for the same item. After Chrysler took over some of the names changed yet again.
I tend to use the name everybody else is using, even if the manual or catalog says something else.

 

[SteelHeadz]

Check for spark. if you don't have spark and the PCM does not see any reference signal from the Crankshaft Position Sensor then the CKP is morelikely to be at fault. it's located between the engine and trans. on the bell housing driverside.i could be wrong.

 

[midnight special]

I'm going to run the multimeter on the crank position sensor and check all other suggestions. Really appreciate it, I was going a bit nuts.

 

[ka041a]

i think it is unlikely that the cps would have failed entirely all at once, more likely it would cause misfires ans set a trouble code, and put the system into limp-home mode, but i'm not that familiar with the GC system. try spraying a little starting fluid in the intake. this will tell you if it's the fuel system or not. hope this helps, john

 

[Bounty__Hunter]

But they didn't make the GC until '93?