Since your temps are much higher than before, I would submit that it's likely that either you're previous temp readings were wrong, or your current ones are, particularly in regard to "negative" oil pressures.  I think you need to be very sure you're EM-2 is calibrated, and not by just matching one number to a gauge.  Check a low, mid, and high level to make sure the EM-2 is correctly calibrated. 

Agreed. I wish I knew an easy way to do that.

 

John;

Maybe no easy way; but I’d also recommend checking calibration; although my oil pressure using the VDO sensor from Tracy seemed to be quite close based on reading -2 at 0 and a max of about 100, which is the setting of the RB relief valve. I think I have recalibrated about every channel except the thermocouples; and changed some just a wee bit, and some a lot.  In two cases I had different senders.  It seems the calibration is installation dependant.

 

Here’s the procedure I used, and Tracy can alert us if I’m leading you astray.  Borrow (or buy) an infrared pyrometer (temp gun) for easy checking of oil and coolant temps.  Paint about a 1” circle of flat black paint on surfaces that you want to measure, and hold the gun right up against, maybe a 1/8 to ¼” away for consistent accurate readings.  Set the low end offset at about 120-130F and set the sensor offset equal to the ADC readout at that point.  Adjust the scale factor to get the correct high end reading at about 210F. Repeat the same points again.  You may have to adjust the sensor offset, and the scale factor a bit.

 

For OAT and other aux air temps, use a water container (a coffee mug works good) and a good thermometer. For OAT, use some ice to get a water temp down to 40F or less to set low end offset and sensor offset, and some warm water to set the scale factor to get the high end correct at about 100. Put the tip of the air temp sensor in the water.  For higher temp ranges like rad air outlet, maybe set the range from about 70F to 150-160F.  For whatever reasons I found the air temps with the RWS senders and the “stock” calibration factors to be considerably off away from the 80F range.  Is the OAT used for TAS and pressure altitude calcs?  If so you’d like to have that pretty close.

 

For the fuel pressure, coolant pressure and manifold pressure I got some 2 – 2 ¼” +- 2% gauges from McMaster-Carr for less than $10 each; 0-60 psi for fuel and -30” hg to 15 psi for MAP.  For calibrating MAP I used the local pressure (engine off) for setting the low-end offset, and set scale factor to get good reading at around 12” hg. (it’s a vacuum gauge, so MAP is local pressure minus the vacuum reading).  For local pressure, I guess you can use the pressure read in the pressure window on your altimeter needed to read an altitude of 0; or get the local barometric pressure, which is corrected to sea level and 60F, and adjust it to your altitude and temperature (remember that old flight computer?).  Be sure the EC2 is on when doing the “low end” with engine off. My MAP reading was off by 3” hg at local pressure of 29.8”before recalibrating.

 

Maybe it’s just me, but before I ever role down the runway I want to know that I have good data.

 

Al