procharger Posted July 6, 2018 Report Share Posted July 6, 2018 After flying with it I now have some kind of grimlin, during 3 flights all of a sudden my CHT and oil temps jump to 350 -400 degrees, done this 3 times, today I landed and stopped engine, while sitting, temps climbed even higher, turned off battery 3 seconds later I turned it back on and readings were normal, I then removed panel unplugged ADSB and flew again for hour with no issues, what the hell? Link to comment Share on other sites More sharing options...
Anticept Posted July 6, 2018 Report Share Posted July 6, 2018 Grounds. Make sure they are pristine. CHT, Oil, and EGT are all sensitive to floating voltages in a EMS 120 (if that's what you have). A GDL-82 doesn't use much power though, so I am curious myself. Still. Those grounds need to be CLEAN! If I recall, you have a CTSW. Put a voltmeter lead on one of the grounds on the post in the upper right corner inside on the firewall, and the other at the battery negative. Turn EVERYTHING on (but engine stays off). If you see more than a couple tens of milivolts, your ground isn't good enough. The lower, the better. Dynon recommends no higher than 5 miliamps but that's really hard to do and would require tearing out the whole grounding system to replace with larger gauge wire. Link to comment Share on other sites More sharing options...
procharger Posted July 6, 2018 Author Report Share Posted July 6, 2018 Are you saying because of the ADSB I might need to redo grounds? Link to comment Share on other sites More sharing options...
Anticept Posted July 7, 2018 Report Share Posted July 7, 2018 I'm saying check them. That should be the first thing you address. Secondly, where is the ground for the GDL-82 run? Does it go all the way to the grounding bolt, or did it get pigtailed somewhere else (bad)? Link to comment Share on other sites More sharing options...
procharger Posted July 7, 2018 Author Report Share Posted July 7, 2018 Looks like is grounded where all the other grounds are inside fire wall. Link to comment Share on other sites More sharing options...
Anticept Posted July 7, 2018 Report Share Posted July 7, 2018 Alright. Check voltage drop as aforementioned. Make sure everything is running. Check voltage drop from the engine too. Link to comment Share on other sites More sharing options...
Cody85 Posted July 28, 2018 Report Share Posted July 28, 2018 2007 CTSW. I have the same problem. CHT, OIL Temp, and even sometimes oil pressure gauge are getting some type of electrical interference causing them to wander about. I've found that when I turn on landing light or interior lights, the gauges will temporarily correct to true, then slowly wander again. Mechanic always tightens wires but problem seems to persist. Any suggestions? Link to comment Share on other sites More sharing options...
WmInce Posted July 29, 2018 Report Share Posted July 29, 2018 First thing I would do is . . . thoroughly check all ground points. Link to comment Share on other sites More sharing options...
Runtoeat Posted July 30, 2018 Report Share Posted July 30, 2018 Wondering if the ignition switch contacts might be involved? Maybe some bleed-thru of voltage into ground circuit? Or, maybe some fluctuating voltage being supplied to the instruments? After many hundreds of cycles, the switch can start acting flaky. Link to comment Share on other sites More sharing options...
sandpiper Posted July 30, 2018 Report Share Posted July 30, 2018 On 7/28/2018 at 4:44 PM, Cody85 said: 2007 CTSW. I have the same problem. CHT, OIL Temp, and even sometimes oil pressure gauge are getting some type of electrical interference causing them to wander about. I've found that when I turn on landing light or interior lights, the gauges will temporarily correct to true, then slowly wander again. Mechanic always tightens wires but problem seems to persist. Any suggestions? I don't think just tightening grounds is the answer. You need to take them apart and scotchbrite (scuff) all the connections - even if they look clean. Link to comment Share on other sites More sharing options...
procharger Posted July 31, 2018 Author Report Share Posted July 31, 2018 After cleaning every ground you can get to, it may fix the problem, it fixed mine. I don't understand why these planes are picky about grounds?? Link to comment Share on other sites More sharing options...
Anticept Posted July 31, 2018 Report Share Posted July 31, 2018 Because the wiring design is the worst part. A lot of hodgepodge half dones. There are wires using the shielding as a ground. While acceptable (barely), it's not preferred. Shielding is meant to be used as shielding, not as a current carrying conductor. And it doesn't have the mechanical flexibility of copper. The grounding design should have used a terminal block (pre LS) or ran a heavy ground to the terminal block and bonded to both strips (LS+) rather than used a bolt, which corrodes. Link to comment Share on other sites More sharing options...
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