D180 CHT's and EGT's

Wondering if anyone has had this problem.

I havent started the engine yet, however, after wiring all of my engine firewall forward items up some time ago, I was reading everything correctly. More specifically, I was reading the ambiant temperature of the hanger.

For some reason today, I noted that all of the Cht's and Egt's were reading -99?

The only wiring change I have made was to splice into the power line to the red cube (pin 15 of db 37) so that I would have the power to both of the Dynon Capacitance-to-Voltage Converter, where i have wired them up to Pin 20 and 21 and then the grounds.

A little perplexed to say the least.

I disconnected the battery and the connectors in the back of the Dynon to no avail.

Suggestions?

My first thought was that the 25 pin D-Sub connector for thermocouples was not plugged in. But then you said that you checked the connectors. A test can be done to check the D-180 by shorting out a thermocouple. Remove the connector. Use a jumper wire or small paper clip and plug it into a thermocouple input in place of an EGT or CHT probe. The D-180 should then display ambient temperature for that cylinder. If it doesn't, then either the jumper is plugged into the wrong holes or else something is wrong inside of the D-180, perhaps the setup.

As an old school computer programmer I learned about 50 years ago that when a new problem appears the first thing to do is undo your last change!

Sorta there...

Thanks for the input.

Went back to what I adjusted last, which was splicing into the Pin 15 of DB37, the Fuel flow 12V red wire.

With the splice and hookup to the cap volt convertors (not hooked to tank), I get the faulty reading on all CHTs and EGT's of -99. I removed the ground associated, no difference. I remove pin 15 from the DB37, replace the harness into the D180 and presto, Normal CHT and EGT reading the ambiant hanger temperature.

Any idea what could cause this?

Thanks

Fixed.

I got it figured out...I re-did the connectors including the ground....reconnected, no issues

I removed the ground to verify....-99 returned.

Thanks for the input.

Don