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93 ZJ Oil Pressure Problem

Discussion in 'Grand Cherokee' started by TinyInkognegroT, Jan 3, 2020.

  1. Jan 3, 2020 at 9:55 AM
    #1
    TinyInkognegroT

    TinyInkognegroT [OP] Well-Known Member

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    Noticed over the last few days, my oil pressure gauge needle drops to 0 then back to 80 when I'm in Park and idle. It also drops at a stoplight. Doesn't seem to drop at 35-65 mph. My oil pressure has always read 80psi since the oil pressure sending unit replacement. Wasn't worried about it too much, until now I'm hearing a faint tick from the engine and my oil level shows I have oil.
     
  2. Jan 3, 2020 at 4:13 PM
    #2
    Jim Beam

    Jim Beam Well-Known Member

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    Electric oil pressure gauges and sending units do have a history of going bad in time. I would suggest a mechanical unit either setup for an easy temporary mount or permanent. That is really the only way to know for sure.
     
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  3. Jan 3, 2020 at 7:34 PM
    #3
    Jrgabriel

    Jrgabriel Well-Known Member

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    Just curious - should oil pressure ever drop? I’ve been having multiple problems but I did notice the other day that oil pressure drops from 48 apx to 23 when put in park...
     
  4. Jan 3, 2020 at 8:42 PM
    #4
    aggrex

    aggrex Well-Known Member

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    In general there will be fluctuation with engine rpm but zero is not normal.
     
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  5. Jan 3, 2020 at 9:02 PM
    #5
    Jrgabriel

    Jrgabriel Well-Known Member

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    Right - so are saying it is normal to drop in half...?
     
  6. Jan 3, 2020 at 9:40 PM
    #6
    aggrex

    aggrex Well-Known Member

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    As mentioned best to confirm with a mechanical gauge but oil pressure will be lower at idle than on the road at cruising speeds. Assuming your EVIC or gauge is relatively accurate I think your #s look fine. Oil viscosity, oil overdue for change, current PCM>sensor>pump relay>ETC unresolved issues could affect these readings.
     
  7. Jan 4, 2020 at 4:16 AM
    #7
    TinyInkognegroT

    TinyInkognegroT [OP] Well-Known Member

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    What's a good example of a mechanical alternative? I just bought the new replacement about 2 months ago...
     
    Last edited: Jan 4, 2020
  8. Jan 4, 2020 at 4:13 PM
    #8
    Jim Beam

    Jim Beam Well-Known Member

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    For my mechanical gauge I use an Autometer mechanical along with purchasing their stainless steel hose for it.
     
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  9. Jan 4, 2020 at 8:06 PM
    #9
    JKBob 25

    JKBob 25 Well-Known Member

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    Way over thought. Imo. But I'm no expert. Yes...pressure will drop at idle. And will increase as engine rpms increase. Zero is not normal. But gauges are for the most part off plus or minus 2 to 4 psi off. Agreed...hook up an outside manual gauge. But they are still not 100% actuate. I've had several motors, Chevy, Mopar, and Flats, run at 0 at a stop light. And 40 plus at 40 mph. It all depends on the motor. My opinion. Unless your pressure is constantly bouncing around. Your good. Also, as mentioned. You can run a slightly higher viscosity oil. But personally. I'd stick with the manufacturer recommends.
    But just my 2 cents.
     
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  10. Jan 5, 2020 at 4:24 AM
    #10
    TinyInkognegroT

    TinyInkognegroT [OP] Well-Known Member

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    It randomly drops and rises whether I'm at a light, parked, or driving on the main streets and highways. I don't notice it too much while I'm driving because it's hard to watch the road and watch the gauge but at times when I've had the chance to look, I've seen it drops to zero and bounced back up to 80 psi whenever I'm driving on the main roads or highways. The only reason why I'm worried is because of the ticking and it seems like my engine is running a lot harder. But I'm not missing any oil. Starting to think oil pump is going bad
     
  11. Jan 5, 2020 at 4:25 AM
    #11
    TinyInkognegroT

    TinyInkognegroT [OP] Well-Known Member

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    How would I install a mechanical gauge?
     
  12. Jan 5, 2020 at 4:32 PM
    #12
    Jim Beam

    Jim Beam Well-Known Member

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    The easiest way would be to tap into the oil pressure sending unit location, they are usually 1/8" pipe fittings and are located on the or near to the oil filter. You could tap into the threaded outlet thread with a 1/8" brass tee fitting. An autometer oil pressure gauge has a 1/8" male pipe fitting, this can be attached directly or by using a stainless braided hose( Autometer sells them) and install the gauge permanently or temporary inside the vehicle.
     
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  13. Jan 5, 2020 at 5:55 PM
    #13
    aggrex

    aggrex Well-Known Member

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  14. Jan 8, 2020 at 2:14 AM
    #14
    TinyInkognegroT

    TinyInkognegroT [OP] Well-Known Member

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    What about the possibility of a clogged oil pump or gummed up oil pan ? They say oil pumps go out around 150k miles and mine is at 195k.

    Every since I changed leaking oil pressure sending unit, my oil pressure has been 80 psi and has stayed there. Here over the last week, it jumps from 80 to 0 and back and forth as I'm driving. When I first start it up, the oil pressure jumps to 80 psi and will stay there until after about 5 minutes of driving and then it drops to zero and then it'll randomly rise to 80. After a while driving and I'm parked letting the engine run the oil pressure stays at 0 psi and light ticking starts and gets a little noisier as my RPMs rise and I have my foot on the pedal. It's not much of a noise unless my OD solenoid locks up my third and fourth gear and I'm unable to shift into third with the RPMs at 3000 or when slow shifts between shifts I can really hear the ticking but it hasn't worse'n into a knock or loud ticking but the engine does run a little rough like it wants to die, especially after it's been drove for a while. Starting to think it's my oil pressure pump failing.
     
  15. Jan 8, 2020 at 2:19 AM
    #15
    TinyInkognegroT

    TinyInkognegroT [OP] Well-Known Member

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    JKBob 25 likes this.
  16. Jan 8, 2020 at 5:52 AM
    #16
    aggrex

    aggrex Well-Known Member

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    My preference is not to use+return but that's your choice. Good tool for your personal arsenal
     
  17. Jan 9, 2020 at 3:04 AM
    #17
    TinyInkognegroT

    TinyInkognegroT [OP] Well-Known Member

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    Turns out my engine oil was low
     
  18. Jan 17, 2020 at 6:47 PM
    #18
    JKBob 25

    JKBob 25 Well-Known Member

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    :annoyed:. Should have been the first thing you check dude. Me personally, just assumed you did. You should always start with the basics. And go from there. Just my 3 cents dude.
     
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  19. Jan 17, 2020 at 7:15 PM
    #19
    Jrgabriel

    Jrgabriel Well-Known Member

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    I did have them check it and I also took it to Autozone to put a load test on it. They all said battery was good but Autozone said it was good but at 41%. I posted about this too. Not certain if this fixed it....and I’ll know more tomorrow - but come on if the Dealership is telling me it’s good and I’m asking...what else can I do? I was and am trying to get it to another shop.

    we will see
     
  20. Jan 17, 2020 at 7:20 PM
    #20
    Jrgabriel

    Jrgabriel Well-Known Member

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    This might be some more bull they pull to get it out of there to not mess with it...we will see. General Manager didn’t come out and say it was fixed but that they put a new battery in it and of course Engine Light went off. If it’s still running rough I can only guess that I have a wire problem, alternator problem or finally a tone ring. No one has confirmed if a tone ring won’t charge that battery correctly and in turn cause my poltergeist windows, locks, and lights...
     

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