freddy

hey all, my 96 xj 4.0 just cut off on way home from work.wont start back. turns over fine ,just wont start. fuel pump comes on. replaced the cps with a factory part last year so I don't think that's it. It hasn't given me a code to read. Just as a side note, over the past month or so ive noticed that it would give a slight jerk every once in a while under load in a high gear. in a months time it did this maybe 5 or 6 times. what do yall think I should check first?

HEAP of JEEP

I wouldn't just rule out the CPS, but start with the basics and figure out what is missing... Fuel, Spark, or Compression. Checking for fuel at the rail is as easy as pushing in the schrader valve, and checking for spark can be done by pulling a plug and grounding it on the block while someone turns the key, and seeing if you have a strong blue snappy spark.

If you're missing one, then you know where to focus your diagnostic efforts. If you have both fuel and spark, then I would rent (for free at some auto parts stores) a fuel pressure tester to test the fuel pressure and make sure it falls within spec... on a 96, I believe you should be around 45 psi at the rail.

Bustedback

A quick and easy test is to spray some starting fluid into the throttle body. If the engine starts briefly on the starting fluid you have a fuel problem. If nothing happens you have a spark problem.

freddy

ill try both ideas. thanks?