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  1. #41
    Join Date
    Feb 2009
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    Dayton Ohio Area
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    6,599

    Question to all you Jeep Experts?

    PS your water leak could be a freeze plug. Also you would eventually have an overheat from loss of coolant and air getting in.

    Are you certain it is a coolant leak?


    Also what gas are you using? The more ethanol the less HP. I noticed on several hi-way trips certain gas stations gas provided better mpg than others. All were reg 87 octane.
    There is a app called pure gas. Maps stations that sell ethanol free gas. It is higher priced and usually 92 octane but if it delivers you will know your issue.

    Never look down on anyone unless you are helping them up - Jesse Jackson
    Last edited by JPNinPA; 11-13-2022 at 10:44 AM.
    "Never look down on anybody unless you're helping him up" - Jesse Jackson

  2. #42

    Re: Question to all you Jeep Experts?

    Good morning,
    Here's the morning update.

    Removed and replaced the # 3 main bearing ( the Thrust Bearing ) the rear of the bearing is worn very thin. The crank is also worn, but that's for another day! The crank had .118 fore and aft movement, I am hoping this was the source of the "knock".
    The new oil pump is installed, the timing chain, sprocket and gear are installed.

    The freeze out plugs are all good and dry, I did find a small leak at the thermostat housing that was migrating down along the head. I am hoping this was the source of the anti freeze leak. I will pressurize the system later today after I get it assembled.

    This thrust bearing is not a new issue in this Jeep. I replaced this same bearing maybe 50 thousand miles ago. Something is causing excessive forward pressure on the crank while operating. No one has been able to give any insight as to why the transmission would pressurize causing pressure onto the crank.



    Question to all you Jeep Experts?-img_1762.jpgQuestion to all you Jeep Experts?-img_1764.jpeg
    [IMG]DSC01433.JPG[/IMG]

  3. #43

    Re: Question to all you Jeep Experts?

    do they make shims to keep the crank walk down? i know that was a fairly common issue on the old vw air-cooled engines and you had to shim the oil slinger against the case halves (or something like that, its been a few years)
    03 rhd tj

  4. #44
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    Question to all you Jeep Experts?

    Ill have to search but I thought i read one year the bearing sizes depended on where the block was made. NJ one set and. M was a different set.

    This may not be jeep or the 4.0 engine. I just recall reading it somewhere.

    Never look down on anyone unless you are helping them up - Jesse Jackson
    Last edited by JPNinPA; 11-16-2022 at 02:12 AM.
    "Never look down on anybody unless you're helping him up" - Jesse Jackson

  5. #45
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    Re: Question to all you Jeep Experts?

    Found this looking for the above mentioned article

    https://dannysengineportal.com/crank...-and-remedies/


    Never look down on anyone unless you are helping them up - Jesse Jackson
    "Never look down on anybody unless you're helping him up" - Jesse Jackson

  6. #46

    Re: Question to all you Jeep Experts?

    Good article,
    Thank you!
    [IMG]DSC01433.JPG[/IMG]

  7. #47
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    Re: Question to all you Jeep Experts?

    Yeah that is what I thought too. Being you mentioned your trans fluid being dark after changing you might have a cause for the thrust bearing. But check it all.

    You do know a trans may take 8.8 quarts to fill from dry. When you change you might only drain 3 -4 quarts.
    You need 3 changes to have replaced 80+% of the fluid. You should drive at least 500 mi between changes.


    Never look down on anyone unless you are helping them up - Jesse Jackson
    "Never look down on anybody unless you're helping him up" - Jesse Jackson

  8. #48

    Re: Question to all you Jeep Experts?

    OK........ The saga continues!! I have not lost my sense of humor!! Although mass amounts of alcohol are sounding pretty good about now!!
    After reassembly earlier in the week, I drove the Jeep around town and highway about 125 miles. All good.

    Friday I loaded it up to travel 900 miles north. With a fully loaded Jeep, complete with two Fat Tire bikes secured on the rear, I hit the roads at 12:30 am after 5 hours of sleep.

    With the added load I can tell by the gas pedal position there is more of a power demand being required. 25 miles into the trip the check engine light aluminates solid, I pull in to check the code, PO304, #4 misfire. I reset and press on. Another 30 miles or so another solid check engine light. I pull in and read the latest code (s). This time it is a PO303 and PO304.

    A note..... The temps are Perfect!

    I reset and continue. About 100 miles into the trip the check engine light starts flashing and there is a noticeable loss of power.
    At this point I limp into a 24 hour fast food proudly displaying the Golden Arch!

    The code reader displays PO300, PO301, PO302, PO303, PO304, PO305 and PO306. Well crap!!!
    I go in and order a coffee and something on a English Muffin!
    I come out, open the hood and swivel the fuel injectors a little to satisfy my need to touch something! I clear the codes and return south.

    The 110 miles back to the house went pretty much the same way.

    I think the temperature issue is resolved.. The fuel pressure was normal throughout this sortie.
    I have ordered 6 factory new, Mopar Fuel Injectors this morning.

    ANY INPUT IS WELCOME!!

    I have already checked the local U-PICK auto parts place. They have a few 4.0L engines available from Grand Cherokees for $350.00. I can see my winter project!!!!
    [IMG]DSC01433.JPG[/IMG]

  9. #49
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    Question to all you Jeep Experts?

    Id pull the plugs and look at them. See that there is no damage. Do any look overheated or sooty?
    Did you have any engine knock or ping??

    Loaded up with tall gears and large tires might end up with a lean condition lower rpm






    Never look down on anyone unless you are helping them up - Jesse Jackson
    "Never look down on anybody unless you're helping him up" - Jesse Jackson

  10. #50

    Re: Question to all you Jeep Experts?

    Plugs all look normal, no knocking or pinging. As for gearing and load... For many years and many miles with this gearing and 33" tires the Jeep was normal.
    I pulled a twin axle, 14' foot flatbed trailer across the USA a few times with NO issues.

    The head scratching continues!

    I will install the factory new, Mopar injectors when they arrive later in the week. Today I will inspect the wire harness that supplies power to the injectors.

    Upon the injector replacement I will load it up and take it out for a test run. If the issue persists, I am prepared to surrender it to a engine/Jeep shop or the dealer to have a crack at it.
    I'm hoping they will have diagnostic equipment that can monitor all the systems feeding info to the computer?
    [IMG]DSC01433.JPG[/IMG]

  11. #51

    Re: Question to all you Jeep Experts?

    What do you think about possible 02 sensor issue? Doesn't the mixture get info from the 02 sensors?

    Bad manifold gasket? I've sprayed carb cleaner all over while engine is running, no rise in RPM.
    [IMG]DSC01433.JPG[/IMG]

  12. #52
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    Re: Question to all you Jeep Experts?

    Quote Originally Posted by Andrew Mac View Post
    Plugs all look normal, no knocking or pinging. As for gearing and load... For many years and many miles with this gearing and 33" tires the Jeep was normal.
    I pulled a twin axle, 14' foot flatbed trailer across the USA a few times with NO issues.

    ?
    How many miles on the motor?
    Not so much about what was but what can be done.

    Besides injectors. Your pressure test was ok. What about Valves sticking or all carbon coated.
    You could seafoam or steam clean.

    Call a local junk yard or weigh station and when loaded see if the would give you a weight.
    Or with all the bikes you might be a bigger brick and not as aerodynamic.

    ???
    Grabbing at ideas!!!



    Never look down on anyone unless you are helping them up - Jesse Jackson
    "Never look down on anybody unless you're helping him up" - Jesse Jackson

  13. #53
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    Question to all you Jeep Experts?

    Did you ever change the O2 sensors? What brand???

    Borrow a scan toll from Oreillys or AutoZone that can show live data. Then look at the switching levels and speeds of the front and rear O2. Fronts should be faster than rear.

    Take a screen shot or post up the numbers.

    Another approach would be to unplug upstream O2s and tie the wires out of the way so they do not melt or get pulled into a tire or belt.,.
    If the misfire goes away plug them back in and see if it comes back.

    I do find it very odd that the misfire isnt directly related to the work you just did. Like the bottom end bearings.

    In that article for bad thrust bearing it noted bad trans. Id verify those items. Esp since you noted dark fluid soon after changing it.


    Never look down on anyone unless you are helping them up - Jesse Jackson
    Last edited by JPNinPA; 11-22-2022 at 10:30 PM.
    "Never look down on anybody unless you're helping him up" - Jesse Jackson

  14. #54

    Re: Question to all you Jeep Experts?

    Good morning,
    Are you familiar with Jeep Service Bulletin # 09-003-03, dated Aug. 1, 2003?
    I can't figure out how to attach a document here!!
    After reading it, I think it's my issue. As I don't own the $400.00 tool they reference , I will just pull the head inspect and de-carbon the valves and guides.
    It states that the valves are suppose to rotate at and above 3200 RPM, thus keeping the build up of carbon from building in the guides and valve itself. WELL...... I hardly get above 2500/2600 RPM. Ever!! I'm sure the valves and guides are full of carbon.

    I will pull the head over the next couple days and keep you posted.
    If you are comfortable emailing me, admacqueen@gmail.com I will email the bulletin to you.
    [IMG]DSC01433.JPG[/IMG]

  15. #55
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    Question to all you Jeep Experts?

    Yes I mentioned the basics in post #38


    Remember all your compression numbers were near stock spec 150.
    Lower was 145 and 140. If you did the leak down test you would know if there was a leak through the valves.

    Do the seafoam and steam to clean valves. Seafoam reduces the oily buildup. The steam drives out the petroleum products leaving crispy carbon that flakes off. Just mist the water in to avoid hydrolock. This would be first step without removing the head. There is no guarantee they spin. It is designed that at above 3200 RPM that the spring tension allows movement and rotation.
    When you did the plugs did you seat them?
    When you did the injectors did all the gaskets /o-rings go on and slide in?
    When you vleaned the TB and IAC did the gasket go back on and seat?
    With so many misfires im thinking vacuum, intake or exhaust leak.

    I will try to give tests and advice in the easiest/cheapest route first.


    Never look down on anyone unless you are helping them up - Jesse Jackson
    Last edited by JPNinPA; 11-23-2022 at 12:28 PM.
    "Never look down on anybody unless you're helping him up" - Jesse Jackson

  16. #56

    Re: Question to all you Jeep Experts?

    Seafoam in the fuel or oil or both?
    Last edited by Andrew Mac; 11-23-2022 at 03:03 PM.
    [IMG]DSC01433.JPG[/IMG]

  17. #57
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    Question to all you Jeep Experts?

    With a warm engine. Spray Into the intake while holding the idle at 1100-2200.
    Immediately shut down engine. Let it soak for 15-20 min. Then drive for a while letting the residuals burn out. Its going to smoke a lot.


    Same when you do steam.


    Video:
    You could add some seafoam to the oil. Though the sticking is on the combustion side
    Does Seafoam Actually Work in a Car? (with Proof) - YouTube

    Never look down on anyone unless you are helping them up - Jesse Jackson
    Last edited by JPNinPA; 11-23-2022 at 07:20 PM.
    "Never look down on anybody unless you're helping him up" - Jesse Jackson

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