Forum Discussion

Bamafam4's avatar
Bamafam4
Explorer
May 30, 2013

Erratic Oil Pressure Cat C9

We were waiting on my friend and his family in a parking lot near the exit we were leaving from, heading to Destin from Birmingham. Sat there maybe 15 minutes and then took off. Engine oil pressure gauge almost immidiately started going crazy. Peaking then dropping. Check engine light came on. Then engine protect mode. Turned coach off and restarted. Same thing. Restarted again and it was better. Decided to try and get on the road. Within 5 miles it was normal and gave me no problems on the way down or on the way home. Also noticed this 1 time briefly on our Gatlinburg trip at Christmas. Oil level is perfect and was changed less than 6 months/ 3000 miles ago. 2005 Fleetwood Revolution Cat C9, 28k miles. Engine runs great and never heard anything funny when gauge was going crazy. Any ideas? Bad filter maybe? Pump going bad? Thanks for your replies.
Class A

10 Replies

  • gatorcq's avatar
    gatorcq
    Explorer
    May 31, 2013
    The CAT engine is not dependent on Oil pressure. The readout is there because people like to see it. The design of the engine and engine controller, oil pressure is not a controlling function inside the ECU.

    The system depends more on the amount of oil in the oil pan.
  • Bamafam4's avatar
    Bamafam4
    Explorer
    May 31, 2013
    Thank you for the replies. Going to take it to the Cat dealer and have them read any fault codes there might be and look at changing the sending unit. This is absolutely the best forum I have been on! I am thankful for the willingness you all have to share your knowledge and experience.
  • Sully2's avatar
    Sully2
    Explorer
    May 30, 2013
    donn0128 wrote:
    First thing i would change would be the sending unit. Then the oil filter. If those dont do it, then i would have a oil pressure check done with a mechanical gage. Lastly i would start looking for a loose connection or bad ground.


    I had a sending unit go crazy...acted just like that
  • siggyd777's avatar
    siggyd777
    Explorer
    May 30, 2013
    Hi Bamafam4, I send you a private message about the fault code password.
    Siggy
  • stardalo's avatar
    stardalo
    Explorer
    May 30, 2013
    Maybe the VDC. I had a similar issue with my 03 Journey withe a CAT 330. My particular issue was an erratic front air gauge. Ended up being a cold solder joint on the VDC.
  • Bamafam4's avatar
    Bamafam4
    Explorer
    May 30, 2013
    Anybody know or know how to acquire the 4 digit password for fault codes on the 2005 Revolution LE?
  • steveownby's avatar
    steveownby
    Explorer
    May 30, 2013
    Bamafam4 wrote:
    We were waiting on my friend and his family in a parking lot near the exit we were leaving from, heading to Destin from Birmingham. Sat there maybe 15 minutes and then took off. Engine oil pressure gauge almost immidiately started going crazy. Peaking then dropping. Check engine light came on. Then engine protect mode. Turned coach off and restarted. Same thing. Restarted again and it was better. Decided to try and get on the road. Within 5 miles it was normal and gave me no problems on the way down or on the way home. Also noticed this 1 time briefly on our Gatlinburg trip at Christmas. Oil level is perfect and was changed less than 6 months/ 3000 miles ago. 2005 Fleetwood Revolution Cat C9, 28k miles. Engine runs great and never heard anything funny when gauge was going crazy. Any ideas? Bad filter maybe? Pump going bad? Thanks for your replies.


    Since your check engine light came on and it went into protect mode, the engine ECM was seeing a problem. The gauge on the dash and the ECM use separate sensors so you may have an issue and the prudent thing to do would be get it checked out. If it was serious enough to go into limp mode then you should have a code set in the ECM history.

    I know I the Cat C7 won't run at all without adequate oil pressure because the fuel injectors run on oil pressure. I'm not sure about the C9.
  • Valkyriebush's avatar
    Valkyriebush
    Explorer II
    May 30, 2013
    My Jeep did that before and it was just the Oil Pressure sending unit. To be sure perhaps a fault code reading will tell you since the check engine light came on?
  • donn0128's avatar
    donn0128
    Explorer II
    May 30, 2013
    First thing i would change would be the sending unit. Then the oil filter. If those dont do it, then i would have a oil pressure check done with a mechanical gage. Lastly i would start looking for a loose connection or bad ground.

About Motorhome Group

38,738 PostsLatest Activity: Jul 26, 2025