2tall2slow

Having a no start issue. If an alternator were completely bad, is that not reason enough to get no spark? Its about the last thing(should've been one of the first)things that I have not checked. Jeep would crank but not fire up. Now wont even crank, battery low on volts. Tested at 11.6V the other day, now reading 7.7V. Have replaced cap, ignition coil and cps with mopar part.

Roler

Your battery voltage is not even close to what your Jeep needs to get started.
With a good, fully charged battery it should be able to start (because the battery is what your jeep uses to get started, the alternator doesn't come in play until the engine is actually running). As to why your battery is low on voltage, that's for later.

First thing before any further parts are changed: fully charge your battery, see if it holds a charge and have it load tested. If it's old, or can't recall when it was replaced, or any doubt about it, get a new quality battery.
A good functioning battery is essential and where it all starts (so t speak).

Let us know how this goes and we'll go from there.

2tall2slow

In the beginning, battery was fine. I had been trying to crank, trying to crank over and over so many times in the begininng, and the voltage was where it should've been. It just wouldn't fire up. I will hook it up to my charger and hope it does some good but I don't know. Battery is new inside of 20 months. I should state that I have actually tried to hook this one up to my other jeep and jump starting and all I get is cranking, still no starting.

Roler

Batteries can be going bad with stuff like this. Once it's drained, some have difficulty getting back up to scratch. Charge till full and have it load tested.

2tall2slow

swapped battery out with different one reading 12.89V. Still crank no start. rechecked spark, no spark at plug #1 at least. Camshaft sensor? not sure how to replace that, correcting timing and all.

Bobthemotorcycle

Its cool, I had no problem while you were on my thread.

2tall2slow

Spoke with my local part dealer/electrician, seems to believe after all of my testing that this piece right here may be the answer to my no start.(since I replaced coil and cps) Even assured me that if this doesn't work, will gladly refund me. I got nothing to lose on this deal but 15min of my time.

Roler

well, let us know how you go then...

2tall2slow

Switched out harmonic balancer, or camshaft sensor, and I heard the sweet sound of my 4.0 again. Have to let it run for a bit to let the computer recognize the new piece, or else problems. Drove it, parked it, drove it some more. Feels good guys. Thanks to all! Thanks Bob, hope you get yours running strong again soon.

Roler

Or? HB has nothing to do with a no start, you likely mean the cam sensor

What is it you exactly mean with "run for a bit to let the computer recognize the new piece, or else problems"

2tall2slow

I refer to the unit in my previous post as the camshaft sensor. Parts dealer called it the HB. I had never even heard tell of that. lol. Maybe everyone has there own terms. Whatever the case, I replaced the camshaft sensor, located under my rotor button. I read that you cannot manually set these so that you need to let jeep run at idle for a few minutes so that the pcm will recognize the change. Worked for me. Love some mopar.

Bobolink

Some parts guys are such clowns!!

2tall2slow

just heard it called a 'hall effect' sensor on another thread. that's why we have pictures.

2tall2slow

I am at a loss. it drove fine for 2 days after replacing cam sensor. Got in it this morning and it would NOT start! Cranks fine, just not firing up again. What now? Is this because I took the cheap way out and used an aftermarket off brand replacement rather than spending double the money for MOPAR brand? Help please.

Bobolink

You mentioned in the first post of this thread that you have replaced the CPS, but haven't mentioned it since. Have you checked the plug on the CPS since replacing it? That connector is a common source of no-start issues. Next time it won't start, try unplugging and replugging the CPS connector.