Shalegreen01xj

So I just bought my first xj 2 days ago from a co worker and it started right up and runs great but when you turn it off it wont fire up again unless you let it sit for half a day, it will crank and crank and crank but but wont fire up unless you let it sit, I replaced the cps on it and I can smell gas in the intake after trying to restart it, it has a 4.0 in it any ideas on what it could be?

Kogulanathan Kasinadan

Try to pull code.
Check for the spark.Because normally a faulty ignition coil can give problem like this.
last time i used to have this problem.When the engine hot wont start and also will stopped the motor after drive like 2 km.This might be to ignition problem so check from ignition coil to spark plug.

tjwalker

This would be considered "thermal failure" of some sort. Here is how I would approach it.

1. Use a code reader or a scan tool and see if there are any "stored" or "pending" codes.

2. Do you have the exact same symptoms with the old and the new crankshaft position sensor?

3. A couple of engine management sensors that come to mind with your situation (after the crank sensor) would be the camshaft position sensor and the coolant temperature sensor. Both can be tested with a manual and a meter.

4. Verifying spark (test coil rail) right away when with a hot engine when it won't start, is a good idea as already mentioned.

jedijeb

I don't know that much about the 4.0, but I have a 4.9 in my F150 that has a leaky injector and it behaves in a similar manner. After short periods of turning the engine off the injector will leak fuel into the intake and flood the engine. Let it sit long enough that the fuel evaporates and all is fine. I have gotten it to start before by holding the throttle wide open while cranking just like with a carb engine and it will eventually clear out and fire up.

Shalegreen01xj

With the new crank sensor it wont fire up at all

97grand4.0

You need some hard data. Start with taking the fuel pressure. If not enough you won't fire. If it bleeds off too fast after shutdown your pump regulator or injector is leaking.

You say cps, do you mean crank position sensor or cam position sensor? Cam sensor and crank sensor must be Mopar ONLY replacements.

Shalegreen01xj

Removed the autozone cps bought a mopar cps and installed it coughed and won't start and just cranked and cranked, still have fuel

Shalegreen01xj

Just read the codes and its saying cam shaft sensor is bad

CurrySoSpicy

can you post the actual codes for us to see? I wonder if there could be an issue with the wiring harness for the sensor.

97grand4.0

That will do it. That code is usually accurate too. Had same problem with mine, is why I asked you if when you said cps did you mean crank or cam sensor.
Same deal on that, mopar only.

Shalegreen01xj

Cps the first time I meant crank sensor, and I just replaced the cam sensor and she fired right up! And I went mopar for cam and crank sensor. Thanks for all the help!

97grand4.0

Glad you figured it out, nothing like checking fault codes!

Shalegreen01xj

Didn't have a scanner before today, but this gave me a good reason to buy one!

97grand4.0

Invaluable tool to have. You can always do the "key trick" and count CEL flashes, but the tool just has so much more. Like graphing and fuel trims.

tjwalker

The "key on, key off" trick won't work for his 2001. The ability to pull two digit codes that way went away for the regular Jeep XJ somewhere midway during the 1997 build year.

After that point, only a code reader or a scan tool can pull codes.