Gedis

Thanks everyone!! Here is my debug plan. Hook up a multimeter to the gauge, reproduce the problem, and check what I see. If signal is not twitching when gauge is twitching - I know I have a bad gauge. If signal is twitching, I'll clean all the terminals and even better, replace the cable. If that doesn't help - need new oil pressure probe. Now the question, how to access the signal wire from cockpit? Is it easy to remove the glareshield? Or is there a way to pull out the gauge?

Thanks! The whole system works well when tested using shop air but when flying, needle starts twitching quite a bit and frequently redlines (engine is ok). From what you said I wonder if cable is broken and causes open circuit thus redlining the gauge. Vibrations could be causing intermittent connection problems.

When oil pressure gauge sensor wire is shorted to ground, would the indication be high oil pressure or low? Trying to figure out what to debug first.

Great, let me reach out to Lasar although I'm never letting them touch my plane again after they forgot to change an oil filter during an annual and who knows whatever else.

Thanks @carusoam! I should have mentioned that my M20K is a 231. Part number for the oil pressure gauge is 640281-141 and Paul's 252 came with a 640281-179. Now I wonder if they are interchangeable but I doubt it. I'm really surprised that there are no drop in replacements. And of course Sigma Tek requires an account to see 169CL-3 documents. Gedis

Oil pressure and CHT gauges (all stock) in my M20K are close to death and need to be swapped. I'm unable to find replacement parts by Googling. Could someone help me with the part numbers? Or even better, maybe one of you are getting a JPI upgrade and would like to sell me your old gauges? What do you think is the cheapest path to get upgraded oil pressure and CHT gauges if direct stock gauge replacement is not an option? JPI currently is not an option.. Thanks everyone for your help.