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joannismyjeep 02-20-2012 05:02 PM

Joann has been sitting for two months. Finally got some of the parts I needed to fix her up, just replaced the coil pack, spark plugs, flywheel, and starter. Basically what happened was she was making a bad knocking noise, gave her 3quarts oil and it got worse. Took her to a local mechanic (mistake number 1) to check out the noise. He says the flywheel is cracked needs to be replaced. Had him replace it (mistake number 2). He calls me up says shes running great, go pick her up make it half a block she stalls and shuts off. Get her started keep going bout a half mile we repeat the process. I got her to my dads house about 2 miles down the road before she cut off again. Called the mechanic (mistake number 3) told him he messed something up. Took it back he says its not his fault, i have a faulty coil pack (he charged me). I did the coil pack and plugs myself, my starter fell apart randomly (its only two years old), replaced that. Shes still stalling and shutting off. Sometimes she starts to stall and then keeps going. Not to sure whats going on. I have heard talk that it may be the Crank Sensor?? Any advice on the matter would be amazingly appreciated.

4wheelin 02-20-2012 05:49 PM

Well, there's lots that could be wrong here. This is one suggestion out of many to help troubleshoot this problem.

Since you have focused on electrical, lets assume something else without going down the original issue of something knocking (clue #1).

Unbolt the catalytic converter. If this thing has all of the pellets inside it seized up, you'll get it hot enough to expand, and it will choke and stall. After cooling for a brief period, you can start it and it will run for a bit, and then stall on you. This is a classic sign of a bad catalytic converter. Riding around for a few miles with it disconnected is loud, but will prove if this is the issue or not.

Post back and let us know, so we can help with cheap ideas.

hardcoretj 02-20-2012 06:13 PM

Good chance it is the crank position sensor. I had a similar intermittent problem when I had one go bad. It seem as if a vehicle sets a while will make them go bad.

joshbarb2 02-20-2012 11:33 PM

have you done the computer test? I think jeeps from 99' and up have it. Put your key in the ignition turn it so the battery turns on and off than on again than off again then on again. So it would go: on, off, on, off, on. This will give you computer codes of whats wrong with your jeep on the odometer!

joannismyjeep 02-21-2012 08:41 AM

4wheelin, unbolted the converter sadly it still shut off. Back to square one :( Josh I have not done the computer test. Didn't know I could do that. How do I read the codes though?

TheTJRod 02-21-2012 10:54 AM

I would think it wouldn't show any codes if his "check engine" light isn't on.

joannismyjeep 02-21-2012 11:08 AM

My check engine light is not on. So should I try this or no? I differ to you alls better judgement :D btw tjrod not that it really matters but I'm a girl :D

TheTJRod 02-21-2012 12:03 PM


Originally Posted by joannismyjeep (Post 2057281)
My check engine light is not on. So should I try this or no? I differ to you alls better judgement :D btw tjrod not that it really matters but I'm a girl :D

Oh.. well let me correct it.

I would think it wouldn't show any codes if her "check engine" light isn't on.

Anyway, to how I understand it is that your PCM turns on the check engine light when it's throwing a code. No light, no codes.

joannismyjeep 02-21-2012 12:50 PM

That's what I thought, works the same way as hooking the handheld to it and figuring out why the light is checking the computer isn't gunna idea? I am picking up the crankshaft position sensor tomorrow $35 at autozone and try that out. Hopefully that fixes it. Any other thoughts?

Thanks for all the help!

joshbarb2 02-21-2012 04:22 PM

When my crank shaft sensor was going out the code still came up on the odometer. As far as how to tell just google it you'll get a big list of codes and their meanings.

4wheelin 02-21-2012 04:44 PM

Can we have more details on the knocking noise you originally posted about? You mentioned you added 3+ quarts of oil. I'm wondering if the noise went away after you added the oil? You were able to travel for a short distance until it cut off. Did the knocking return? Get louder?

I would expect if there was a mechanical failure of some sort to generate the knocking, it would generate a computer code.

In any case, while your at autozone getting the crank sensor, have them check the computer for codes. It's worth the effort, just in case something will show up.

Keep us posted.

4wheelin 02-21-2012 04:56 PM

While you're at autozone, you might want to get an aerosol throttle body cleaner and give yours a good cleaning. I'm assuming you have removed the air filter to make sure it's not starving for air? There's just so many things, it's hard for us (well, me anyways) to pin point it.

C.L. 02-21-2012 05:03 PM

Sorry i don't have a direct link, but do some searching here on flywheels. I remember reading here where someone replaced their clutch/flywheel and had the same issue. Apparently there are many different "keyed" flywheels that talk to the CPS, and transmit info based on when some notches or flags rotate past the sensor. The wrong flywheel will fit physically, but will not transmit the correct timing signal to the CPS. Result is the engine stumbles/stalls, or just won't start at all.

C.L. 02-21-2012 05:12 PM

Here we go, this may be it. Or at least similar.

joannismyjeep 02-22-2012 08:41 AM


Originally Posted by 4wheelin (Post 2058386)
Can we have more details on the knocking noise you originally posted about? You mentioned you added 3+ quarts of oil. I'm wondering if the noise went away after you added the oil? You were able to travel for a short distance until it cut off. Did the knocking return? Get louder?


The knocking didn't go away or change. it was really odd. It didn't knock while I was in drive, or at least not loud enough that I could hear it even with the top down. When I was in park it was terrible. I couldn't hear anything except the knocking. If i put the car in reverse with my foot on the brake I also didn't hear any knocking. I was originally worried about the oil. I checked the dipstick it showed that it was low I added two quarts, put it back up to full. About a week later I checked it again, it was low. I added another quart, less than 4 days later it was low again I put in another quart and called the mechanic worried I had a leak. No leaks, no smoke out of my exhaust but the mechanic swears its burning the oil. The knock was still there. That's when I was told the flywheel was cracked and that was the knock I was hearing. Before the flywheel was replaced I had none of the stalling and shutting off issues. After it was replaced I can't make it down the block.

P.S. To all of you offering opinions...My post that says I differ to you alls better judgement was supposed to say defer...sorry.

4wheelin 02-23-2012 05:45 AM

We understood what you meant. Dont worry about spelling:thumb:

With the loss of oil and the knocking sound, I'm going to go with a broken valve, likely an exhaust valve. When the valve is supposed to retract, it doesn't in your case, which allows oil to seep into the cylinder and get burned. I understand you said there is no smoke coming out the exhaust, which is another indicator of a broken valve, but we want to narrow down the possibilities for you as cheaply as possible.

To test for this, you'll need to take one spark plug out at a time, and use a compression gauge. You can get these at autozone as well. They cost about $25 like this one

Actron/2 1/2 in. quick release compression tester kit (CP7827) | Compression Tester |

Screw in the guage in where the spark plug was. Dont reconnect the coil pack. Crank the engine over once and turn it off. The piston will go through a full cycle (up/down) and compress the air in the cylinder. This will be read on the gauge. Each reading should be pretty close to the same - 120 psi to 150 psi, but maximum variation between cylinders should be no more than 30 psi.

Repeat this for each cylinder. Hopefully one of them is extremely low, and that's the problem cylinder.

I say hopefully only because we want to help you diagnose the problem, and not wishing you have a broken valve. But, if that's it, it's not too expensive to have it repaired and we figured it out.

Since you were able to do so many other tests on this vehicle, I'm hoping this is something you are comfortable doing. If you don't feel confident with this, call around to a few shops and ask them to do this for you. Some shops will reduce the total bill if the valve is found broken and you get the work done there (reduce the costs from the diagnostic so that you don't have to pay as much). That's a generalization, and not true for all shops. I live in an area where this occurs, so I only speak from experience.

Keep trying - we'll get there.

joannismyjeep 03-06-2012 11:12 AM

Hey guys sorry just stopped responding. I cut my hand open two saturdays ago got a bunch of stitches and havent been able ti use my hand since. hoping to get back to joann next week.

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