jeep 98 wrangler 4.0 cranks but won’t start. I’ve tries pretty much everything from changing the ignition coil, distributor rotor and cap, map sensor, throttle position sensor, crankshaft position sensor, checked for voltage into the ignition coil which there is. Checked all fuses. But the thing just won’t start. Going to change the camshaft sensor but really running out of options here. Any help would be much needed. Thank you
Jeep cranks but won’t start
- Thread starter esteban__8
- Start date
stop throwing parts at it ! are you sure you have no spark ? also if your using the wrong sensors (oreillys, autozone , ETC...) you might cause more troubles.
I'll echo this, as a former survivor of a crank no start issue myself. Do the basics first which cost nothing. Check all your major connections, pull them apart, put them back together make sure there's good contact. Process of elimination. Trace your wires thoroughly from the PCM to their end points looking for damaged wires.
Thread 'Solved: Jeep died on me tonight, now won't start' https://wranglertjforum.com/threads/solved-jeep-died-on-me-tonight-now-wont-start.66299/
and don't throw away your old sensors.....
Do you get RPM on the tach when cranking?
Will it run a little if you spray something flammable like starting fluid or brake cleaner down the throttle body?
-Mac
Will it run a little if you spray something flammable like starting fluid or brake cleaner down the throttle body?
-Mac
I’ve traced all the wires and checked them for voltage same with connectors and everything seems to check out good
Using good parts and. That was my first guess not getting a spark. I’ve made sure there’s voltage going into the distributor and checked all wires to make sure there good.
Here are a few more things to consider:
Fuel Delivery: Make sure you're getting fuel to the engine. Check the fuel pump to see if it's priming when you turn the ignition on. You can also check the fuel filter and verify that there are no blockages.
Fuel Pressure: If you have a fuel pressure gauge, it’s worth checking the pressure to ensure it’s within the specs for your Jeep.
Spark: While you confirmed there’s voltage to the ignition coil, you should also check for actual spark at the plugs. If there’s no spark at the plugs, it might still indicate an issue with the ignition system.
Engine Grounds: Double-check all your ground connections. Bad grounds can lead to a variety of electrical issues that can prevent the engine from starting.
Error Codes: If you haven't already, use a scan tool to check for any stored error codes in the ECU. This could give you clues about what might be wrong.
Starter Relay and Ignition Switch: Even if the engine cranks, there could still be issues with the starter relay or the ignition switch itself.
Camshaft Sensor: Since you mentioned you’re going to change the camshaft sensor, definitely do that—it can sometimes be a culprit in preventing the engine from firing.
Try giving her a shot of starting fluid or carb cleaner down the throat and see if it starts
The only codes that are showing are the throttle position sensor which p0121 and the camshaft position sensor p0340, and the fuel pressure looks good. Thank you for the help
and you've already replaced those . might be time to page @Wranglerfix to the bat phone ! your PCM might be giving up !
Ok, so I JUST spent a month chasing my tail on a crank, no start, no spark condition in my TJ. When it shit the bed, I had an ignition coil code and the same P0340 for camshaft position sensor as you. I changed both plus crankshaft position sensor and lots of others. Here's the kicker, my gut told me from jump that it was the distributor, but I kept talking myself out of that being the problem. In my testing, I was able to immediately eliminate the dreaded ASD relay circuit because I found that my ignition coil was getting the 12v at key on, then again while cranking. Timing was right, grounds good, 45psi at fuel rail, etc. All my sensors had 5v reference, signal back to pcm, and good ground. What I also found is that even though I had voltage at the coil, my PCM wasn't sending a pulsed ground to the coil, which is what makes the spark happen. The PCM will only send this pulse when it's happy with the camshaft and crankshaft signals. Both those were new, and NTK brand sensors, so I went on to change igntion components, tear into wiring harness, pull my hair out, and attempt to deal with the devil..all to no avail. Finally, I pulled the cap off my distributor, checked that the rotor spins during cranking, pulled new camshaft position sensor/pick up coil, and with it came the pulse ring. The pulse ring is supposed to be attached to the distributor and it shouldn't come out attached to the sensor or anything else. Bingo. There it was. A month of frustration and headache for that. New distributor and running strong.
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