Printable View
When I turn on the pitot heat the cylinder head temperatures go from 450 to 650 and the exhaust gas temperatures also go way up. To a lesser extent this will happen when I turn on the landing lights. It seams that the more amps, the hotter the gauges read. The software level is S8.6.8-MV15
Thanks!
This is not a software problem, most likely you have a grounding issue.
1. What type of plane is this in?
2. What are you using for your engine case ground?
3. What does the Oil Temperature do when the alternator load goes up? This is a good test for bad engine grounds.
4. Make sure you don't have any CHT or EGT fast on connectors touching the engine case at the probes.
5. Do you have an 18ga EFIS case ground wire connected?
1. RV6A
2. If I understand the question correctly, I believe the ground wire from the battery goes to the engine case. It was wired following Vans instructions.
3. I do not recall it reacting like the CHT and EGT but do not know for sure.
4. Not sure what a fast on connector is but assume that it is the thing that you push in and twist into the bottom of the cylinder head. I will have to look.
5. Most likely but not sure.
Everything worked fine when the probes where hooked up to the Rocky Mountain Engine Management box. Never had and issue with the temps spiking with increased amps. All I did was move the wires from the old box to your box.
Most of the Rocky Mountain systems used grounded EGT and CHT probes, our system is designed to work with ungrounded probes. Remove one of your probes and see if you have resistance between one of the connectors and the probe tip, you should not have resistance.
I trouble shot this at great lengths, I found that on the alternator, there is a loop wire, used as a lead to an overvoltage light. I found out (don't ask me how....) that by cutting this loop, all my problems went away. I found that every time I turned on the boost pump for landing, the oil temps went over redline, now they don't!
Regards,
Gary Brown ATP A&P IA CFI DAR
Gary,
what kind of alternator do you use? (Model)
I have a similar problem. It happens only when I use my gear pump and only the oil temp changes.
Christian
Plane power. call me (503) 269-3907
What you are describing is caused by not having a good engine case ground connection. On my RV-10 I have two braided case ground straps. If you still have difficulty we have a two wire oil temp probe that will solve it.Quote:
Originally Posted by lancair390
Rob,
after my winter break I will work on this little problem. I made an extra engine ground already, but did not help.
I have some more ideas to modify my ground wiring. If all this doesn't help, I will be happy to try the new probe.
Christian
There is also a wire on some alternators that should not be connected and will cause this problem.