Chasing a ghost. Need experienced help- Oil Pressure

Discussion in 'KJ General Discussion' started by Mator1988, May 23, 2020.

  1. Mator1988

    Mator1988 03 liberty sport 3.7l

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    Oil light(red can with drop) comes on when I press the brake. I have replaced the pressure sensor 2 times. Changed the oil, filters new oil(synthetic blend), change back to covental oil plus did oil pressure check with manual gauge(flushed motor this time). A friend and mechanic told me to go with 20w50 so I did. Said oil pump was weak, that when I speed motor up the oil pump speeds up too. It has thrown multiple different codes. I change spark plugs it help some put new MAP helped a little. Now I'm using 89 instead of 87. I've researched. Results could be battery or pcm or vac leak. I've replaced crankcase breathers and pcv line. I'm ready to torch it but I love my jeep. Please old wise hands help me out. It's my first jeep( just empty every pocket ) first 4x4 and first vehicle with AC. It has a 3 inch lift before I bought it. Only had it almost 3 months
     
  2. LibertyTC

    LibertyTC Well-Known Member Staff Member Moderator

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    Welcome to the forum.
    Sorry for all the questions but here we go..Did you use an after market or the better quality Mopar oil pressure sensor?
    When you depress the brake pedal once & hold down, do you hear any hissing or a bit of an air leak?
    Does the rpm drop at all when you depress the pedal ? What is the idle rpm in Drive, Jeep Hot when stopped?
    What was the manual oil pressure reading in psi ? How many miles on your Jeep now?
    What are the Problem Codes numbers?
    Triple check the larger hose coming off the brake booster for any cracks or wear.
    Hoping that the oil pressure will increase with a thicker oil may not be the best plan, that's old school, in a newer tight tolerance engine.
    Unless it is very seriously burning oil, you should use the 5w-30, (especially if the pick up screen is restricted) it will flow & lubricate better & is what's specified by Jeep.
    The pump could be weak depending on psi #s and dropping the pan and installing a new pump, cleaning screen, would be the best solution.
    Looking forward to see the oil psi numbers at idle & revved up at 2000 rpm.
     
  3. Mator1988

    Mator1988 03 liberty sport 3.7l

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    $35 sensor. Didn't get the cheaper one.
    Haven't noticed an air leak when braking
    Idles round 700rpm with 10psi
    3000rpm around 75 psi
    148750 give or take a couple
    P0158 p0158 p0838 p0151 p0300-p0305 coil packs codes had a few more. Charging system low. Checked with multi meter. B-12.8 off A-12.9 off. B-13.7 idle a- same. Pulled + off stayed running
     
  4. Mator1988

    Mator1988 03 liberty sport 3.7l

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    Was using 5w30 in reg oil and synthetic blend. Had it put on computer at shop. Oil pressure was all over from 0.05-101.3 and in between. said jeep was 180 out of time. Cant believe that or it wouldn't run and if it did it wouldn't have be so smooth. I could see it jump a couple teeth had new oil pump rod bearings done before I got plus heads were sent off
     
  5. LibertyTC

    LibertyTC Well-Known Member Staff Member Moderator

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    How many miles on this Jeep?
     
  6. Mator1988

    Mator1988 03 liberty sport 3.7l

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    148,750 give or take maybe 12miles
     
  7. LibertyTC

    LibertyTC Well-Known Member Staff Member Moderator

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    $35 sensor?- Did you install a Mopar oil pressure sensor?
     
  8. Mator1988

    Mator1988 03 liberty sport 3.7l

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    No sir. Discontinued. O Reilly's crossed referenced to the after market
     
  9. Mator1988

    Mator1988 03 liberty sport 3.7l

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    Do you think I need to order it from Chrysler? I've checked the harness didn't see anything. not shorting out or grounding out that I could see or find
     
  10. LibertyTC

    LibertyTC Well-Known Member Staff Member Moderator

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    Yes absolutely. Only the Mopar can be trusted & will be calibrated correctly for the KJ's Pcm.
    BTW the Mopar sensor will only turn on the oil light if it was to drop below 4 psi.
    For now, I'd say get the Mopaar sensor installed and see if the light still comes on.
    The manual psi test dropping that low even after the new oil pump has been installed, has me quite concerned.
     
  11. LibertyTC

    LibertyTC Well-Known Member Staff Member Moderator

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    Let me see if I can find the Mopar pressure sensor online stand by..
     
  12. Mator1988

    Mator1988 03 liberty sport 3.7l

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    I read at 650 rpm it shouldn't be lower than 4psi. Friend told me to hook up manual gauge and go for a good drive and watch the gauge when it's in operation. do you agree that I need to try that
     
  13. LibertyTC

    LibertyTC Well-Known Member Staff Member Moderator

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  14. Mator1988

    Mator1988 03 liberty sport 3.7l

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    Ok I feel like that would be alot to drill extra hole in block. I've replaced the oil pressure switch located right above the oil filter. What I saw is either I don't have a 3.7l motor. Or the jeep body is listed as 03 and motor out of 04
     
  15. tommudd

    tommudd Moderator Staff Member Moderator

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    Yes try using the correct MOPAR oil sensor
    Have installed a few that people bought from their local rip off store only to have them come back with same issue
    Personally I would NEVER run oil 20W50 oil when it calls for 5W30
    I have an 04 I bought new with over 232,000 miles on it and 5W30 still does great in it ( well use 5W30 full syn in all 3 of mine)
    Guys used to do that back years ago if selling a junker and trying to get one over on a possible new owner
    also running 89 instead of 87 is just costing you more money, not helping

    03 with a 04 motor ????????
    First it won't work without someone doing a ton of work to the 04 motor to make it work in an 03
     
  16. Mator1988

    Mator1988 03 liberty sport 3.7l

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    Cold start she ilde at 1000 rpm whit no sound. After about 4 minutes she warmed up and in best way to say it half whine half wirl sound and drops to 700 idle
     
  17. Mator1988

    Mator1988 03 liberty sport 3.7l

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    And it was set up poor man style to do a little rock climbing
     
  18. Mator1988

    Mator1988 03 liberty sport 3.7l

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    My dad said turn idle screw
     
  19. Mator1988

    Mator1988 03 liberty sport 3.7l

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    No air leak on the lines I was referred to to check. Adjusted idle screw. I thank you gentlemen for the knowledge yall have passed on to me. I will order switch from dealer
     
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  20. tommudd

    tommudd Moderator Staff Member Moderator

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    should drop to 700 at idle