HELP!!! Changed Alternator, Engine turns over but won't start

[Warthog]

Hi,

Over here from the Short wheel base forum. I did a favour for my sister(always regret favours for family) and changed the dead alternator in her 91cherokee 4.0l. Now the engine cranks but won't start, it's turning over quickly, so I know the battery still has enough charge. I disconnected the battery over night as well just incase the computer had a code stuck in it or something. Tried it this morning and still the same thing. No check engine light or anything?

Any ideas?

Thanks in advance for the help.

[vegachris]

Hello, to what it sounds it is cranking, so it is not a battery, starter, or alternator issue. Second you need to find out if it you are getting fuel(there is a fuel purge valve on your fuel rail) if fuel squirts out you are getting fuel. Next you need to find out if you have spark, unplug a sparkplug wire and crank your jeep and see if you are getting spark, if there is no spark it can be a pick up coil (under your distributor cap), your ignition coil, your crankshaft position sensor, or your pcm. Most common on the 4.0 is the crank sensor it runs about 30 dollars and can be found on most parts stores. Please let me know how it went, good luck!