TheDale

Yes, I have searched and the search engine brings up so many random threads it's not even worth searching.

So, I have fuel. I have power to the coil, spark coming out of the coil, but no spark coming out of the distributor? Does the cam sensor fire the coil? So that should be good right? If there is spark coming out of the coil, what is left? The cap and rotor?

The engine ran absolutely beautiful this morning, let it sit all day, went out to start it, it fired, stumbled and now it wont even try to start, just cranks over.

Please help.

tjwalker

The #1 suspect for a no-start with NO SPARK is the crankshaft position sensor. It is a very common fail on the 4.0.

Here is a thread that may be helpful. Good luck and check back with us and let us know what you find!

http://www.jeepforum.com/forum/f11/c...ailing-639123/

TheDale

Awesome link, thank you.

My only concern is that, all my gauges work fine. It doesn't have any of the symptoms besides for the crank and no start.

Does the crank position sensor tell the coil to fire? 'cause my coil is firing.

TheDale

Anybody else know anything besides the CPS?

What tells the coil to fire? 'cause the coil has power and it sends juice out the coil wire that goes into the Dist cap. But nothing comes back out the cap.

TheDale

Could it be as simple as the cap and rotor? I tried unplugging the crank position sensor and plugging it back in, that didn't do anything. I have never had any of the symptoms, it's never stalled or anything before, and it usually starts right up, even when it's cold as ****.

Does the distributor even do anything? What does the Cam position sensor control?

If anyone can steer me in the right direction I would greatly appreciate it.

tjwalker

If you have verified that you have no spark at the SPARK PLUGS, (test for spark at the plugs) then the crank sensor is absolutely still the #1 suspect.

TEST IT.

You do not have to have any other symptom other than a no-start. In some cases, people have gauge symptoms, but most often it is just no-spark.

The #2 suspect is the ignition coil itself, but my money is on your crank sensor. These things fail OFTEN on the 4.0

TheDale

Thanks for the help.

Coil is firing hot, I did a cap and rotor 'cause it was pretty bad anyways. Still didn't fix it. But while I was at Napa, I picked up the Crank sensor anyways. It's just to damn cold to install it.

In the meantime, any other suggestions would be appreciated.

Oh, and I guess I am lost on using my MM. I have only used it for volts and don't know anything about testing the ohms of something.

tjwalker

Let us know if the crank sensor fixes this.

TheDale

I definately will. I am gonna play with my Multi Meter and see IF I can figure out how to measure the OHms in the mean time.

TheDale

After Reading that other thread. Someone mentioned the Cam sensor inside the distributor. Could it be that sensor?

TheDale

I was reading my Chilton. And the Cam sensor basically just figures out where the #1 cylinder is at. And then it knows where to fire the coil, in conjunction with the crank sensor. It also says that if the Cam sensor fails while running, it will stay running based off of the last reading. But after it's been shut off, it wont restart.

I just need to get out there and start testing them. But when it's -0 degrees and I cant get it into the garage. I can't stay out there very long.

TheDale

Well, I tested the cam sensor, and it checks out ok.

I just can't test the crank sensor by myself.

I have both the sensors. But I don't want to install both of them if only one of them is bad. I wish I had it in my garage so I could keep working on it. Laying in the snow at night sucks.

TheDale

And I ohmed the Crank sensor. It ohms at 3.8, but the new one I got ohms out at 1.8 so wth?

But, i'm pretty sure it's the crank sensor. 'cause I tested the cam sensor and when I spun the engine it went from 0 volts to almost 5 volts like it should, except it was only like 4.8 volts but that shouldn't really make a difference.

freegdr

did you check for codes even if the cel light is not on

TheDale

No, I have no way of checking them.

Is there a trick do doing it myself? I am new to jeeps. But have had many cars before.