High Oil Pressure Indication

[Berniepiet]

I have a GRT EIS engine monitoring system linked to a GRT Sport EFIS system, Circa 2007.

I was receiving an Intermittent hi well pressure message. The oil pressure was showing over 99 psi. This has now become a constant indication. I am not seeing any oil coming out of the engine due to excess pressure. Thinking it might be a sensor problem.

Is anyone familiar with the GRT EIS system and its sensors? Is there an oil pressure sensor that could be replaced before I dive into the oil pressure regulator itself? The folks at GRT Tech support are at Oshkosh. I had planned to fly to Oshkosh, but can’t until I get this issue resolved.

Thanks

[m.mooney]

I would check the ground, I’ve had this issue on my grt eis and it was the ground. The 99 is not an accurate pressure reading but a default indication for electrical issues, if I recall correctly. If you don’t have the owners manual, I’d download it, the troubleshooting section is pretty good.
Mike

[whee]

99 means open circuit. Check your wiring to the sensor. The sensor is just a VDO type and it could have failed but I’d check the wiring first.

[Berniepiet]

I would check the ground, I’ve had this issue on my grt eis and it was the ground. The 99 is not an accurate pressure reading but a default indication for electrical issues, if I recall correctly. If you don’t have the owners manual, I’d download it, the troubleshooting section is pretty good.
Mike

Thanks. Will do!

[Berniepiet]

99 means open circuit. Check your wiring to the sensor. The sensor is just a VDO type and it could have failed but I’d check the wiring first.

Thanks! Will check it out

[svyolo]

If it has a separate ground wire, you can try clean both ends of the ground wire/studs. If it is single wire, the case is the ground. Remove the sensor, run a die over the sensor threads, just slightly, and a tap through the other threads, just slightly.

A quicker way than the tap/die to troubleshoot is slightly loosen the sensor, then tighten it back down and see if the reading is different.

[Berniepiet]

If it has a separate ground wire, you can try clean both ends of the ground wire/studs. If it is single wire, the case is the ground. Remove the sensor, run a die over the sensor threads, just slightly, and a tap through the other threads, just slightly.

A quicker way than the tap/die to troubleshoot is slightly loosen the sensor, then tighten it back down and see if the reading is different.

Thanks. I will try that

[Berniepiet]

If it has a separate ground wire, you can try clean both ends of the ground wire/studs. If it is single wire, the case is the ground. Remove the sensor, run a die over the sensor threads, just slightly, and a tap through the other threads, just slightly.

A quicker way than the tap/die to troubleshoot is slightly loosen the sensor, then tighten it back down and see if the reading is different.

This is the sensor. Is it grounded by the hose clamp holding it on the firewall? Should I just clean off the sensor and re mount it?

[jaredyates]

It may also ground through the hose. I am surprised that it doesn't end up wirh air bubbles, shouldn't it be flipped over? I'm not an expert in thess things by any means.
i would suspect the joint between the riveted strips and firewall more so than the hose clamp.

[Battson]

Mine are all that way up, no issues in the last 870 hours

[whee]

Power on the EFIS, disconnect the wire from the sensor and check oil pressure indication (should indicate 99). If that checks good then connect the sensor wire directly to a good ground and check oil pressure indication (should indicate 0). Since your issue is intermittent after ensure the above indications I would visually check the wiring while wiggling the wires to make sure indication remains constant. I would do this while the wire is grounded and indicating zero.

The hose clamp is providing the ground to the sensor.

[svyolo]

Also just check resistance between the body of the sensor, and engine or airframe ground. As sensors get older, their connection to ground corrodes. The power wires, not so much.

[Berniepiet]

Something I noticed. Upon taxi back the oil pressure reading was fluctuating between 99 and 98. If it was an intermittent ground, would it fluctuate between 99 and the actual oil pressure?

[zkelley2]

100% it's the ground or sensors connection to ground.

[Berniepiet]

Changed the sensor. It seems to have cured the problem

[JimParker256]

My Rotax powered RANS S-6 also has the GRT EIS system, and I had some fluctuating oil pressure indications. A buddy who knows both the Rotax and EIS systems quite well suggested removing the lead wire, cleaning those connections thoroughly. I did so, and after I put it back together, I've had zero issues since then. Rotax engines are generally not an "oily" environment, but I guess it managed to find enough "gunk" to create electrical issues. From what I hear, the sender units themselves rarely are the issue – it's almost always the wiring at one end or the other (or both!).
PS - I really like the GRT EIS system.

[zkelley2]

The VDO senders are notoriously unreliable. They're crazy cheap though... so.. keep a spare.