Oil pressure gauge sender reading low
Discussion
My oil pressure gauge is reading a bit lower than it used to, and I think it’s most likely to be the sender’s fault.
It’s only a bit low - it used to read 30 when idling (hot) and 45-50 at high revs (hot), and about 60 when started from cold.
Nowadays it’s more like 15-20 when idling hot, and 30-40 at high revs. Perhaps 45 when started from cold.
Am I right in thinking that the sender’s resistance is low at high pressure, and high at low pressure, i.e. low current is low pressure and high current is high pressure?
If that’s right then it might be worth jacking up and cleaning the contacts to the sender, which may either be corroded or oiled up - hence higher resistance, lower current, and lower gauge reading.
Or have I got it the wrong way round, and dirty contacts would show a higher reading?
Mine is an after-market sender with a separate earth, that I fitted many years ago. I guess it could be on its way out.
It’s only a bit low - it used to read 30 when idling (hot) and 45-50 at high revs (hot), and about 60 when started from cold.
Nowadays it’s more like 15-20 when idling hot, and 30-40 at high revs. Perhaps 45 when started from cold.
Am I right in thinking that the sender’s resistance is low at high pressure, and high at low pressure, i.e. low current is low pressure and high current is high pressure?
If that’s right then it might be worth jacking up and cleaning the contacts to the sender, which may either be corroded or oiled up - hence higher resistance, lower current, and lower gauge reading.
Or have I got it the wrong way round, and dirty contacts would show a higher reading?
Mine is an after-market sender with a separate earth, that I fitted many years ago. I guess it could be on its way out.
Edited by Dr Mike Oxgreen on Saturday 23 September 16:46
I also have the sender with extra ground to chassis wire.
Ippsso or Isspro or something like that, can’t remember without looking
Your top set of pressures are very high.
Your second set far closer to actual pressure usual for a Tvr RV8 engine imho.
My actual oil pressure using a conventional oil pressure gauge reads very close to your second set of figures.
My car gauge reads somewhere in between both your sets of figures so slightly hi but never reads 60 Psi.
It looks good on the gauge though
A TVR engine guru once said as low as15psi at a hot idle is normal.
Your question is an interesting one though and I too look forward to hearing the answer
Ippsso or Isspro or something like that, can’t remember without looking
Your top set of pressures are very high.
Your second set far closer to actual pressure usual for a Tvr RV8 engine imho.
My actual oil pressure using a conventional oil pressure gauge reads very close to your second set of figures.
My car gauge reads somewhere in between both your sets of figures so slightly hi but never reads 60 Psi.
It looks good on the gauge though
A TVR engine guru once said as low as15psi at a hot idle is normal.
Your question is an interesting one though and I too look forward to hearing the answer
I have a similar thing - I've just serviced my Chim, and a good blob of oil landed on the connectors strapped to the chassis rail in that area.
I also took the sender out to clean it and added a layer of PTFE to seal a potential leak - though I'm beginning to think it's the valley gasket even though it's only done 10k miles since a major rebuild.
I have low readings, sometimes down below the gauge markers on the dash, but the engine is happy, so I'm thinking it's the connections rather than anything more. I'll be giving them a good wipe with some kitchen towel and see it if helps.
I also took the sender out to clean it and added a layer of PTFE to seal a potential leak - though I'm beginning to think it's the valley gasket even though it's only done 10k miles since a major rebuild.
I have low readings, sometimes down below the gauge markers on the dash, but the engine is happy, so I'm thinking it's the connections rather than anything more. I'll be giving them a good wipe with some kitchen towel and see it if helps.
PabloGee said:
I have a similar thing - I've just serviced my Chim, and a good blob of oil landed on the connectors strapped to the chassis rail in that area.
I also took the sender out to clean it and added a layer of PTFE to seal a potential leak - though I'm beginning to think it's the valley gasket even though it's only done 10k miles since a major rebuild.
I have low readings, sometimes down below the gauge markers on the dash, but the engine is happy, so I'm thinking it's the connections rather than anything more. I'll be giving them a good wipe with some kitchen towel and see it if helps.
The sender is earthed through contact with the sump so not sure PTFE is useful here. I also took the sender out to clean it and added a layer of PTFE to seal a potential leak - though I'm beginning to think it's the valley gasket even though it's only done 10k miles since a major rebuild.
I have low readings, sometimes down below the gauge markers on the dash, but the engine is happy, so I'm thinking it's the connections rather than anything more. I'll be giving them a good wipe with some kitchen towel and see it if helps.
The original senders especially when hot tend to read a bit low.
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