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Oil pressure sender

MarkCFI

Active Member
I was flying at normal cruise and noticed my oil pressure was a over the 90 psi limit. Oil temp normal. Reduced throttle and no real change to pressure.

Landed and noticed oil pressure gauge indicated normal reading again. Pulled the cowl and noticed that there appears to be a ground wire clamped to the external part of the sender and it looks a little scruffy.

Searched forums here and it sounds like a bad ground on a single wire sender may be the cause of a false high reading.

So my plan is to clean the wire up and the external portion of the sender where clamped and test to see if it reads normally again and if not replace the sender. Does this sound reasonable?

nTSP7t7FxCmBsfRf7
 
I was flying at normal cruise and noticed my oil pressure was a over the 90 psi limit. Oil temp normal. Reduced throttle and no real change to pressure.

Landed and noticed oil pressure gauge indicated normal reading again. Pulled the cowl and noticed that there appears to be a ground wire clamped to the external part of the sender and it looks a little scruffy.

Searched forums here and it sounds like a bad ground on a single wire sender may be the cause of a false high reading.

So my plan is to clean the wire up and the external portion of the sender where clamped and test to see if it reads normally again and if not replace the sender. Does this sound reasonable?

nTSP7t7FxCmBsfRf7
Perfectly.
A while ago my OP shot up inexplicably while taxiing - I shut down and shot off an inquiry to VAF just like you. The responses indicated that sender failure is the most common cause of that. Turned out to be true in my case at least.
 
Thanks Randall

Just got back from my hangar. Cleaned up the wire and the fitting it clamps to. Will test as soon as we get decent weather. If it fails again does not seem like a hard fix to replace.
 
Recurring topic. VDO pressure senders wear at the variable resistor's wiper arm and tend to read high. Adding case grounds help make them accurate until they wear at the wiper contact, then they tend to read high until they can fall or get tapped back onto the unworn range of the resistor.
 

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Thanks as well

The current oil pressure sender is a “Rochester”..

The gauge reads from zero to 100 (redline) so I’m assuming any of the 0 -100 psi senders would be a good replacement?

I’m hoping it’s the ground wire but honestly I typically don’t have much luck with the simple fix so I need to identify the appropriate replacement and plan putting it in.

Stewart Warner 411K ?

Any recommendations appreciated.
 
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