I just finished 24 hours inspection. During test run, oil pressure jumped to 5.2 bars right after start, and dropped to 4 bars when RPM increased to 2500-3000. Going to idle - back to 5.2, and it continues with this funny pattetn. Higher RPM - lower pressure, lower RPM - higher pressure.

Any ideas? Air in the system maybe?

Thanks, Ran

  • Re: Oil pressure

    by » 9 months ago

    Is this happening after the engine is warmed up or still cold?

    If you suspect air in the system did you take anything that had to do with oil apart? 

    This may be caused by a poor ground wire connection. If the pressure follows the rpm, i.e. goes way down with throttle increase and way up on throttle decrease, trying tightening all the grounds in the engine compartment and inside on the main ground bus bar connection. I've had this happen a few times. 

    Roger Lee
    LSRM-A & Rotax Instructor & Rotax IRC
    Tucson, AZ Ryan Airfield (KRYN)
    520-349-7056 Cell

    Thank you said by: Ran Giladi

  • Re: Oil pressure

    by » 9 months ago

    The engine started cold (35-40C).

    I did simple oil change (tank and filter). Did not open any hose.

    I met the grounding issue with the temperature senders (CHTs and oil), not the pressure one. I'll check it again tomorrow, although grounding seems to be right.

    Thanks Roger.


  • Re: Oil pressure

    by » 9 months ago

    I was experiencing very similar fluctuations in my oil pressure.  At Roger's suggestion, I checked and cleaned the ground connection of the oil pressure sender, and the problem went away.  I now inspect that connection every time I have the cowling off, just to avoid a repeat.

  • Re: Oil pressure

    by » 9 months ago

    OK, I checked it today again. Same same. The engine is new, and the installation seems to be OK, i.e., having an oil pressure PN 956413 or 456180 (I don't remember now) and according to the G3X installation manual (no grounding at the sender, just in the plug connected to the GEA24 as shown in the scheme).

    It starts at 5.1-5.2 bars at startup, even at hot engine, and drops to 4.1-4.2 bars on high RPM. Sometimes it behaves as expected, i.e, rises a bit when increasing RPM.

    Can it still be an issue of the ground (resistor or ?)

    31298_2_Oil pressure sensor connection.png (You do not have access to download this file.)

  • Re: Oil pressure

    by » 7 months ago

    The strange oil pressure remains. Can someone think of a reason? Here are two graphs, obtained from the Garmin system:

    31891_2_Oil_Pressure_Takeoff.png (You do not have access to download this file.)
    31891_2_Oil_Pressure_Cold.png (You do not have access to download this file.)

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