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#1
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I was out flying this evening (Beautiful evening in North Georgia. We don't
get better flying weather than today...) and noticed that my oil pressure was "stuck" at 100 PSI. I reduced throttle and RPM, no change, I increased throttle and RPM, again no change. I tapped the face of the gauge. No change. Eventually, I shut down the radios and transponder and turned off the master switch. The OP gauge fell to zero. Back on with the master and it's 100 PSI again. By the time I returned to my home field, the pressure gauge seemed to be acting normal again, so I presume it is going to be an intermittant problem - the absolute worst kind to diagnose. Anyway, the gauge and sender are both Rochester brand. Probably 6 years old (4.5 years flying)with 350 or so tach hours on 'em. How do I diagnose the problem when it recurrs? Thanks in advance. KB |
#2
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Kyle Boatright wrote:
I was out flying this evening (Beautiful evening in North Georgia. We don't get better flying weather than today...) and noticed that my oil pressure was "stuck" at 100 PSI. I reduced throttle and RPM, no change, I increased throttle and RPM, again no change. I tapped the face of the gauge. No change. Eventually, I shut down the radios and transponder and turned off the master switch. The OP gauge fell to zero. Back on with the master and it's 100 PSI again. By the time I returned to my home field, the pressure gauge seemed to be acting normal again, so I presume it is going to be an intermittant problem - the absolute worst kind to diagnose. Anyway, the gauge and sender are both Rochester brand. Probably 6 years old (4.5 years flying)with 350 or so tach hours on 'em. How do I diagnose the problem when it recurrs? This is a gauge with a remote sender mounted on the engine, right? I ask that because what you are describing sounds like a wetline gauge with some air in the line and cold oil. Maybe the sender is dying. Can you see if the voltage in the electrical line between the gauge and sender varies with oil pressure? Then you could eliminate one part or the other. |
#3
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![]() "Jim Carriere" wrote in message .. . Kyle Boatright wrote: I was out flying this evening (Beautiful evening in North Georgia. We don't get better flying weather than today...) and noticed that my oil pressure was "stuck" at 100 PSI. I reduced throttle and RPM, no change, I increased throttle and RPM, again no change. I tapped the face of the gauge. No change. Eventually, I shut down the radios and transponder and turned off the master switch. The OP gauge fell to zero. Back on with the master and it's 100 PSI again. By the time I returned to my home field, the pressure gauge seemed to be acting normal again, so I presume it is going to be an intermittant problem - the absolute worst kind to diagnose. Anyway, the gauge and sender are both Rochester brand. Probably 6 years old (4.5 years flying)with 350 or so tach hours on 'em. How do I diagnose the problem when it recurrs? This is a gauge with a remote sender mounted on the engine, right? I ask that because what you are describing sounds like a wetline gauge with some air in the line and cold oil. This is an electronic gauge with a sender mounted on the engine accessory case. Maybe the sender is dying. Can you see if the voltage in the electrical line between the gauge and sender varies with oil pressure? Then you could eliminate one part or the other. You could, but that would mean working awfully close to a flailing prop. I'm not up for that. ;-) KB |
#4
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![]() "Kyle Boatright" wrote in message ... "Jim Carriere" wrote in message .. . Kyle Boatright wrote: I was out flying this evening (Beautiful evening in North Georgia. We don't get better flying weather than today...) and noticed that my oil pressure was "stuck" at 100 PSI. I reduced throttle and RPM, no change, I increased throttle and RPM, again no change. I tapped the face of the gauge. No change. Eventually, I shut down the radios and transponder and turned off the master switch. The OP gauge fell to zero. Back on with the master and it's 100 PSI again. By the time I returned to my home field, the pressure gauge seemed to be acting normal again, so I presume it is going to be an intermittant problem - the absolute worst kind to diagnose. Anyway, the gauge and sender are both Rochester brand. Probably 6 years old (4.5 years flying)with 350 or so tach hours on 'em. How do I diagnose the problem when it recurrs? This is a gauge with a remote sender mounted on the engine, right? I ask that because what you are describing sounds like a wetline gauge with some air in the line and cold oil. This is an electronic gauge with a sender mounted on the engine accessory case. Correction, this gauge is mounted on the firewall, and has a 12" or so hose connecting it back to the oil pressure pick-up port on the engine. KB |
#5
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![]() "Kyle Boatright" wrote in message ... "Kyle Boatright" wrote in message ... "Jim Carriere" wrote in message .. . Kyle Boatright wrote: I was out flying this evening (Beautiful evening in North Georgia. We don't get better flying weather than today...) and noticed that my oil pressure was "stuck" at 100 PSI. I reduced throttle and RPM, no change, I increased throttle and RPM, again no change. I tapped the face of the gauge. No change. Eventually, I shut down the radios and transponder and turned off the master switch. The OP gauge fell to zero. Back on with the master and it's 100 PSI again. By the time I returned to my home field, the pressure gauge seemed to be acting normal again, so I presume it is going to be an intermittant problem - the absolute worst kind to diagnose. Anyway, the gauge and sender are both Rochester brand. Probably 6 years old (4.5 years flying)with 350 or so tach hours on 'em. How do I diagnose the problem when it recurrs? This is a gauge with a remote sender mounted on the engine, right? I ask that because what you are describing sounds like a wetline gauge with some air in the line and cold oil. This is an electronic gauge with a sender mounted on the engine accessory case. Correction, this gauge is mounted on the firewall, and has a 12" or so hose connecting it back to the oil pressure pick-up port on the engine. KB Man, I can't get things straight this morning. The sender is on the firewall, fed by the 12" hose. Sheesh. No wonder I rarely post in the AM. KB |
#6
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Yeah, it looks like your snippit button fails at midnight also.
Jim "Kyle Boatright" wrote in message ... Sheesh. No wonder I rarely post in the AM. KB |
#7
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Is the hose clear? Sounds almost like you have a check valve in the line.
Did you make up the hose by putting on ends? If you made the hose or had it made to length, there is a possibility that a "donut" has been cut out of the hose side wall making a flapper valve. Happens when someone doesn't use a mandrel. -- -- Cy Galley - Chair, AirVenture Emergency Aircraft Repair A Service Project of Chapter 75 EAA Safety Programs Editor - TC EAA Sport Pilot wrote in message ... "Kyle Boatright" wrote in message ... "Kyle Boatright" wrote in message ... "Jim Carriere" wrote in message .. . Kyle Boatright wrote: I was out flying this evening (Beautiful evening in North Georgia. We don't get better flying weather than today...) and noticed that my oil pressure was "stuck" at 100 PSI. I reduced throttle and RPM, no change, I increased throttle and RPM, again no change. I tapped the face of the gauge. No change. Eventually, I shut down the radios and transponder and turned off the master switch. The OP gauge fell to zero. Back on with the master and it's 100 PSI again. By the time I returned to my home field, the pressure gauge seemed to be acting normal again, so I presume it is going to be an intermittant problem - the absolute worst kind to diagnose. Anyway, the gauge and sender are both Rochester brand. Probably 6 years old (4.5 years flying)with 350 or so tach hours on 'em. How do I diagnose the problem when it recurrs? This is a gauge with a remote sender mounted on the engine, right? I ask that because what you are describing sounds like a wetline gauge with some air in the line and cold oil. This is an electronic gauge with a sender mounted on the engine accessory case. Correction, this gauge is mounted on the firewall, and has a 12" or so hose connecting it back to the oil pressure pick-up port on the engine. KB Man, I can't get things straight this morning. The sender is on the firewall, fed by the 12" hose. Sheesh. No wonder I rarely post in the AM. KB |
#8
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![]() "Kyle Boatright" wrote You could, but that would mean working awfully close to a flailing prop. I'm not up for that. ;-) How about checking it at the back of the gauge? If you can't do that, Hmm. Replace the sender? -- Jim in NC |
#9
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![]() "Kyle Boatright" wrote Anyway, the gauge and sender are both Rochester brand. Probably 6 years old (4.5 years flying)with 350 or so tach hours on 'em. That is a lot of time and hours on a sender. I would be surprised if it is not the sender. Most senders fail when oil gets past the pressure side, and gets into the dry side. You really can't usually see the problem, but sometimes, you can see oil (a small amount) oozing out around where the wires hook on. If you put voltage onto one lead of the sender, you should see the other terminal voltage go up and down with RPM. If not, bad sender. You can check the gauge by inputting differing voltages, from zero to 12 (or 28) and watch the oil pressure go up and down. If the sender is fairly inexpensive, replace it. It is due. Your mileage may vary. -- Jim in NC |
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