No start issue
 

Don't flame me guys. Lol

My girlfriend's xj wouldn't start. I tried to shift into neutral to start it, it cranked but wouldn't fire. The battery and starter still read 12 volts. I could smell gas in the "exhaust" and I checked the fuel delivery, everything is good. The lights were bright and all.
All battery connections are good.

Then I tried wiggling the trans lever while starting, then suddenly everything went off. The dash lights, etc.

All fuses are intact, I'm stumped here.

Could it be ignition coil or crankshaft position sensor?

"then suddenly everything went off."

Ground issue.

I checked and refreshed all grounds already

I went ahead and tested the battery while turning the key, the voltage dropped to 6, so I went to the store and had battery replaced (under warranty).

I took out the starter and had it tested, found it was still good so I put it back, but not after cleaning the contact posts and sandpapered the wire lugs.

Checked the NSS wire connection at top of engine and its fine.

Cleaned the posts on battery when putting new one back on.

Replaced the crank sensor with eichlen brand from napa.

AND IT STILL WOULDN'T START! It cranks strong but no fire.

I'm starting to think the ignition coil may be at fault. Any ideas?

Let's talk about "quality" of spark. I'd definitely test it; it's vitally important to know where you are at with it. Or if you have spark at all. Testing for spark and quality of spark is absolutely, positively the next step here.

Easy to do on a 99 (ask me how I know).......remove a plug, keep it attached to the plug wire, place the plug electrode near a good engine ground. Have a buddy (or your girlfriend) crank the engine over while you watch. You are looking for a strong, BLUE, snapping spark. Yellow/orange/white indicates a weak spark which may not be strong enough to start the engine.

**If you have weak spark, test your ignition coil. The coil on a 99 can easily be tested for both primary and secondary resistances with a meter and a manual.

**If you have good spark, the next step is to attach a noid light to one of your injectors to be sure they are firing.

**If you have no spark, start by swapping the ASD relay in the power distribution center (black box under the hood) with another relay. These relays are all the same part number so swapping is not an issue. More on the spark route for your 99 below.

Test your way to a solution here; good luck and keep us updated with what you find!
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Spark: 12 volts from ignition switch to the ASD relay; when the key is first turned on the PCM provides a ground to the ASD relay to energize it, then the ASD relay passes 12 volts to the coil primary side. If no crank sensor signal is generated after a couple of seconds the PCM cuts the ground to the ASD relay (and fuel pump relay too) and that cuts power to the coil (and fuel pump). Key to START and once again the PCM energizes the ASD relay. Now, a critical element is the crank sensor--no signal from the crank sensor and the PCM won't trigger the coil to provide spark.

Thank you, and its a 98.

I ll do the spark test now.

98 is same as 99 for all practical purposes here. Update us on spark!

It's orange.

That's weak spark.Test or replace your ignition coil.

If you end up replacing it, an OEM style coil is all you need. Stay away from MSD and other coils that promise you the moon; they won't give you any advantage on the low tech 4.0 engine, and they have a significantly higher failure rate.

Keep us updated!

So BWD or Accel is out of question?

You just don't need a high performance coil for this engine. And because they have a pretty high failure rate in my opinion (I won't install them), why pay the extra money and take the chance?

Don't take my word for it. Search and you'll find plenty of others that have been very surprised to see their high perf. coil fail in a very short period of time.

So u are saying BWD is high performance and I should stay from it? I'm surprised cause I have always thought of BWD as oem style and accel as performance.

Sorry, BWD is fine. Don't get the Accel.

Got it! Thanks

Did you check the Dist cap or rotor ?