wbwillmott
New Member
- Joined
- Sep 16, 2011
- Messages
- 4
I just replaced the cowl and added a plenum but did not do any instrumentative work and now my oil temp has gone nuts. I decided to replace the sensor because it always bounced around a few degrees. Also, replaced the fuel pressure sensor because it's been bouning between normal and 99 and it is dead solid. No work was done behind the panel.
First run did have the oil cooler on the firewall feed by a scat tube. Fearful the temp was truly high, I moved the cooler back to the back baffle for plenty of air mass to pass through.
New oil sensor went up to 245 degrees and was bouncing around. Put old sensor back in and got a bouncing 228 to 250 degrees. Turn on landing lights and get 350 degrees which is the equivalent of a completed closed circuit. Old sensor had 498 hours on it.
Checked with a volt ohm meter against the charts from Dynon. resistance shows a higher temp on both sensors now than the laser does anywhere on engine. Unhooked the sensor wire and EMS shows 1 degree which indicates an open circuit. Also, the temp the EMS displays agrees with the resistance shown on the sensor (obviously without the engine running). Give impression that box is reading the resistance it's getting from the sensor.
Both sensors are bouncing around about 20 degrees. Circuit load raises the temp by 90-100 degrees shown (landing lights, keying mike, strobes, etc..). It didn't use to do this.
Put ground connection on the sensor with a #16 wire under a hose clamp and connected it directly to ground, no change.
Laser temp checked last 3 test flights and everything normal range.
3 minutes after landing, these are temps I got on the last flight - dipstick oil (185), oil filter (187 base and 155 top), engine case multple places (190-205), top of engine (201), oil cooler (154)....... EVERYTHING. CHT's running in 350's. Thank goodness because I'm not worried about the actual temp, just chasing down this goblin.
Turned off the engine and and the temp dropped and held steady at 207 after last flight even though I couldn't get a laser reading anywhere near that high anywhere on the engine, including the oil filter base and oil on dipstick.
When engine is running, only the oil temp fluctuates and drops after engine is turned off.
Engine is grounded (metal airplane) by #2 cable to bolt near battery and battery has a braided 6" ground strap.
Replaced sensor wire back to firewall and routed away from mags in case stray current getting in wire. Mags were just overhauled. Ring terminal solid. No change.
Can't find a nicked/frayed wire.
Made sure the nut/washer stack was clean and terminal couldn't connect to ground.
All other sensors on the engine that feed the EMS D10 are rock solid (CHT's, EGT's) and don't vary when engine is running.
I've ordered another sensor (thsi time a GRT) just in case it may be a sensor.
One thing I haven't done is to pull the alternator connections and clean around them in case there is any oil or debris that allow some current cross over to the engine.
Another possibility is the D10 is sick and needs to be sent back but it seems to be reading the resistance and displaying properly the temp against what the Dynon chart values are.
Three flights and the rapidly fluctation display (only oil temp), excessive temp but does not agree with laser, 100 degree jump on load, is repeatable.
I'm looking for possible solutions or any other ideals.
Thanks in advance for any help.
First run did have the oil cooler on the firewall feed by a scat tube. Fearful the temp was truly high, I moved the cooler back to the back baffle for plenty of air mass to pass through.
New oil sensor went up to 245 degrees and was bouncing around. Put old sensor back in and got a bouncing 228 to 250 degrees. Turn on landing lights and get 350 degrees which is the equivalent of a completed closed circuit. Old sensor had 498 hours on it.
Checked with a volt ohm meter against the charts from Dynon. resistance shows a higher temp on both sensors now than the laser does anywhere on engine. Unhooked the sensor wire and EMS shows 1 degree which indicates an open circuit. Also, the temp the EMS displays agrees with the resistance shown on the sensor (obviously without the engine running). Give impression that box is reading the resistance it's getting from the sensor.
Both sensors are bouncing around about 20 degrees. Circuit load raises the temp by 90-100 degrees shown (landing lights, keying mike, strobes, etc..). It didn't use to do this.
Put ground connection on the sensor with a #16 wire under a hose clamp and connected it directly to ground, no change.
Laser temp checked last 3 test flights and everything normal range.
3 minutes after landing, these are temps I got on the last flight - dipstick oil (185), oil filter (187 base and 155 top), engine case multple places (190-205), top of engine (201), oil cooler (154)....... EVERYTHING. CHT's running in 350's. Thank goodness because I'm not worried about the actual temp, just chasing down this goblin.
Turned off the engine and and the temp dropped and held steady at 207 after last flight even though I couldn't get a laser reading anywhere near that high anywhere on the engine, including the oil filter base and oil on dipstick.
When engine is running, only the oil temp fluctuates and drops after engine is turned off.
Engine is grounded (metal airplane) by #2 cable to bolt near battery and battery has a braided 6" ground strap.
Replaced sensor wire back to firewall and routed away from mags in case stray current getting in wire. Mags were just overhauled. Ring terminal solid. No change.
Can't find a nicked/frayed wire.
Made sure the nut/washer stack was clean and terminal couldn't connect to ground.
All other sensors on the engine that feed the EMS D10 are rock solid (CHT's, EGT's) and don't vary when engine is running.
I've ordered another sensor (thsi time a GRT) just in case it may be a sensor.
One thing I haven't done is to pull the alternator connections and clean around them in case there is any oil or debris that allow some current cross over to the engine.
Another possibility is the D10 is sick and needs to be sent back but it seems to be reading the resistance and displaying properly the temp against what the Dynon chart values are.
Three flights and the rapidly fluctation display (only oil temp), excessive temp but does not agree with laser, 100 degree jump on load, is repeatable.
I'm looking for possible solutions or any other ideals.
Thanks in advance for any help.