• NAXJA is having its 18th annual March Membership Drive!!!
    Everyone who joins or renews during March will be entered into a drawing!
    More Information - Join/Renew
  • Welcome to the new NAXJA Forum! If your password does not work, please use "Forgot your password?" link on the log-in page. Please feel free to reach out to [email protected] if we can provide any assistance.

1998 XJ won't start

sjx40250

NAXJA Forum User
Location
Alexandria VA
This beast has been sitting for several months, 6+. It was involved in an accident and was repaired to the point of running just fine until the oil cooler line broke. It has been repaired tool

It turns over but will not start. The first crank almost started then quit.

The distributor cap and rotor were replaced.

I can't test fuel pressure but there is pressure when the valve is released on the rail.

There is spark, not the greatest, but there is spark.

At a loss of what to attack next. The only think I can think of is the CPS. A new one was purchased but I don't have the right tools to reach way up there in the oil and grunge.

Thought I would ask what I should chase next. Perhaps get an OBD II reader?
 
Buy an OBD-II trouble code reader before you buy a CPS. A deluxe code reader or a plug in with Bluetooth to your phone is better, live data from the PCM is very helpful for diagnostics.

Make sure the battery is fully charged and try starting again while you feather the gas pedal.

The ignition coil should be tested. The CPS can be tested.



For 1996+ Jeeps, the OBD-II engine computer (ECU/PCM) re-boots, and the idle settings are deleted, when you: (1) let the battery run down by leaving the lights or radio on, (2) disconnect the battery for an extended period of time, (3) when the battery goes bad and needs replacing, (4) when the alternator is not properly charging the battery, (5) or when poor battery connections result in a voltage drop at the PCM or poor battery charging. Loose, corroded, or damaged battery cables or ground wires may also cause or contribute to the problem.

A faulty Coolant Temperature Sensor may also cause similar symptoms. Testing of the CTS is recommended as part of the diagnostics. A poor ground at the ignition coil can also cause similar symptoms.

The reboot symptoms are: (1) having difficulties starting the engine without depressing the gas pedal, and (2) the engine will have a low idle and probably stall unless you keep your foot on the gas pedal. (3) The ECU will relearn the idle settings after a short period of driving and the engine will often start and idle normally.

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 or connectors and replace as needed. Copper wires should be copper color, not black or green. Do the same for the grounding wires from the starter to engine block, the PCM, the ground wires at the coil, and the ground wires at the oil dipstick tube. You must remove, wire brush, and clean until shiny, the cable/wire ends, and whatever they bolt to. Jeeps do not tolerate low voltage, bad connections, or poor grounds.

If the symptoms reoccur, you need to have your battery and/or the alternator Load Tested at a repair shop or auto parts store. This is usually a free service they offer to bring in potential customers. Handheld testers are very inaccurate and will usually pass marginal alternators. Even with low battery voltage, the engine will start, but the ECU can re-boot multiple times and a new battery may be required.
 
Last edited:
Just got in from flying from Seatac to DCA.
The battery is new and was charged completely up. New alternator too. This all happened last year and it hasn't been run for quite some time. The battery was completely dead so a reboot is likely.

Would using starter fluid work?

Recommendations for which OBD II Reader?
 
Back
Top