TCU after wrong battery connection
in 912 / 914 Technical Questions
8 years ago
Well, J seem to be the only stupid guy to mix up the positif and negative side when changing the battery. Thats what happened when J replaced my standard orange Pb one last spring for an Li-Fe-ion battery. When starting the 914 UL engine ( 700 hrs) in my MCR4 (2006), the noise J heard was sufficiently different from what J was used, to realize my error J think in less than 2 seconds. J stopped immediately and put back the standard orange PB battery red to + and black to -. The engine went on immediately and turned normally. The only problem was the black-out of my transponder. After repair, J flew several times for about 1 hr each time and then a 1200 miles trip from Switzerland over Corsica down to Sicily. During take-off with full throttle down there, my master switch ( which has a fuse) went into the OFF position and the motor started coughing. As J knew this problem from 5 years ago in exactly the same situation - about 1 minute of full throttle and about 500 ft over ground, J put the nose down, the master back ON and reduce power. The engine came back to normal immediately. As we didn't notice any other problem, we decided to continue our flight up through Italy. No problem the next morning after an over-night stop half way: Take of with full power and another three hours of flight over the alps at 10'000 ft back home. There, we replaced the DUCATI battery regulator, which had been accused the first time and did a successful test flight. One week later, the motor refused starting, even with a good car battery, as it had done already once before the Sicily trip. Changing all candles didn't help. We then changed the ignition boxes and brought back to life the engine, but without the RPM indicator!! We then replaced this instrument that actually proved to be broken down. The new one worked only, when linked directly from the sensor to the instrument. It didn't work when passing through the TCU.
And that's how J was flying my aircraft to the maintenance facility last week for service.
There, the mechanic was unable to check the TCU because of problems to connect the TCU to his computer. J now intend to fly my aircraft to another mechanic for testing.
The questions now are:
Has anybody done the same stupid thing and what were the consequences?
Are we safe flying with the actual configuration, that is the RPM instrument not passing through the TCU? We think, that in case of a problem during flight, it should be good enough switching OFF the Turbo in a "idle power" position and continue like this.
Do we have to replace the TCU?
Would you recommend this just in order to make sure that we have replaced all electronic parts possibly damaged by the wrong battery connection?
Or is the TCU protected against this type of maltreatment?
What has the TCU to do with the RPM indicator or - put in another way - why does the RPM indicator does not work when connected normally, that is passing through the TCU? And why does the TCU works normally without the information from the RPM sensor?
Where on the internet can J find information from the different manuals concerning this subject?
A lot of questions!! Thanks for any help.
Rudolf.
And that's how J was flying my aircraft to the maintenance facility last week for service.
There, the mechanic was unable to check the TCU because of problems to connect the TCU to his computer. J now intend to fly my aircraft to another mechanic for testing.
The questions now are:
Has anybody done the same stupid thing and what were the consequences?
Are we safe flying with the actual configuration, that is the RPM instrument not passing through the TCU? We think, that in case of a problem during flight, it should be good enough switching OFF the Turbo in a "idle power" position and continue like this.
Do we have to replace the TCU?
Would you recommend this just in order to make sure that we have replaced all electronic parts possibly damaged by the wrong battery connection?
Or is the TCU protected against this type of maltreatment?
What has the TCU to do with the RPM indicator or - put in another way - why does the RPM indicator does not work when connected normally, that is passing through the TCU? And why does the TCU works normally without the information from the RPM sensor?
Where on the internet can J find information from the different manuals concerning this subject?
A lot of questions!! Thanks for any help.
Rudolf.
