Encore Posted March 1, 2016 Report Posted March 1, 2016 (edited) The factory installed Turbine Inlet Temperature gauge in my 1997 252 Encore has developed the palsy. It used to be steady as a rock and agree with the JPI gauge but lately the needle swings wildly. I've replaced the probe and had the gauge rebuilt to no avail. I can't find any problem with the wiring (chaffing, ect). Any ideas on how to troubleshoot this? Thanks Short youtube video of the gauge in action Edited March 1, 2016 by Encore Quote
carusoam Posted March 1, 2016 Report Posted March 1, 2016 Welcome aboard Encore. Stand by for the cavalry. Best regards, -a- Quote
takair Posted March 1, 2016 Report Posted March 1, 2016 Are you sure the two gauges use the same probe? Quote
carusoam Posted March 1, 2016 Report Posted March 1, 2016 Keep in mind that TIT TCs are similar to EGT TCs. They live in the harshest environment. I would simply expect that it may be time to swap the thermocouple out. At least take a look at it's physical health. Best regards, -a- Quote
Encore Posted March 1, 2016 Author Report Posted March 1, 2016 10 hours ago, takair said: Are you sure the two gauges use the same probe? Each gauge has it's own thermocouple probe. Quote
Encore Posted March 1, 2016 Author Report Posted March 1, 2016 10 hours ago, carusoam said: Keep in mind that TIT TCs are similar to EGT TCs. They live in the harshest environment. I would simply expect that it may be time to swap the thermocouple out. At least take a look at it's physical health. Best regards, -a- I had the thermocouple replaced at the last annual. It made no difference. 1 Quote
carusoam Posted March 1, 2016 Report Posted March 1, 2016 Something unique to EGT gauges... They may be powered by the differential voltage generated by the the TC. This makes them sensitive to oxidation of the ground connections downstream. It may make sense to check the wiring diagram, hunt down the wire connections, clean and reinstall... PP knowledge only, I am not a mechanic. Best regards, -a- Quote
N231BN Posted March 1, 2016 Report Posted March 1, 2016 Assuming the proper probe was changed and not the one for the JPI I would look at the gauge. The TIT gauges in M20K's are a powered instrument. They still use a TC but the gauge works similar to the JPI, it just has a needle instead of a digital readout. I would check the power or most likely the ground coming from the instrument. 1 Quote
Encore Posted March 3, 2016 Author Report Posted March 3, 2016 On 3/1/2016 at 11:29 AM, N231BN said: Assuming the proper probe was changed and not the one for the JPI I would look at the gauge. The TIT gauges in M20K's are a powered instrument. They still use a TC but the gauge works similar to the JPI, it just has a needle instead of a digital readout. I would check the power or most likely the ground coming from the instrument. Thanks N231BN, The gauge cluster contains all of the other instruments like CHT, OAT, Fuel ect. Is each gauge powered separately or is there one power source for all? I have looked at the back of the gauge cluster it has one large connection point where all the wires enter the housing. How can I determine which wire is the power lead for the TIT gauge? If it is a ground issue wouldn't all of the gauges in the cluster be effected? Thanks Quote
N231BN Posted March 3, 2016 Report Posted March 3, 2016 You are correct, I forgot it is in a cluster on the Encore. Either the problem is internal to the instrument or in the wires to the probe. The probe wires coming out the back of the gauge are white and green and they enter a shielded sleeve marked: DR01B20 I have seen those individual gauges laying around shops before so I assume they go bad over time. Quote
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