D180 and Dynon users

[Don Patrick]

Need some help with the Dynon Manifold pressure sensor.

I had my first engine start the other day with my RV-8....I was pleasantly surprised that it started up on the 2nd blade!

I noted a couple of issues with the D180.

The MAP didnt change and was a constant 32.6 inches and the high voltage warning came alive aftering turning on the Prim Alt on the VP100. The high voltage warning corresponded with 19.6 volts.

The interesting thing was that the VP100 was showing the battery being charged at 14.4 volts and did not provide any alarms.

I disconnected the MAP sensor and the D180 showed a MAP reading of 11.2 inches. I reconnected it and it went back up to 32.6. I removed one side of the line from the sensor and no change.

I'll check the 3 wires again tomorrow for the sensor, but any suggestions on the high voltage on the D180 and nothing on the VP100 would be helpful.

Thanks


Don

[n82rb]

just brainstorming here, but is the MAP sensor tied to ground through the dynon or local airframe ground? i'm thinking it is a potential difference on the grounds causing errors. did you put a volt meter on the buss to see what it was showing?

bob burns
RV-4 N82RB

[lr172]

Originally Posted by Don Patrick

I removed one side of the line from the sensor and no change.

Don

That confirms that that the D180 is not getting data from the MAP sensor or the sensor is not sending it. A wiring issue would be me first guess. One wire is 12 or 5 Volts (don't recall at the moment), another is ground (doesn't matter where it comes from-it) and the third is a variable voltage generated by the sensor, based upon the MAP (0-5 volt range). Without all three, no information can be flowing between the sensor and the D180. I can't recall if 32" is 0 volts or 5 volts. You can look this up and it will help you to troubleshoot your problem. It is an industry standard 1 bar GM MAP sensor.

Have no idea on the voltage issue. The D180 takes this off the main power feed. A bad main ground adding resistance would be my first guess.

Larry

[lr172]

Originally Posted by n82rb

just brainstorming here, but is the MAP sensor tied to ground through the dynon or local airframe ground? i'm thinking it is a potential difference on the grounds causing errors. did you put a volt meter on the buss to see what it was showing?

bob burns
RV-4 N82RB

On this sensor the ground is only used for the sensors power supply. A dirty or unbalanced ground will not impact the performance unless it is bad enough for the power supply to not work. This is a different design than resistive sensors, like the oil temp.

[Don Patrick]

Thanks for the input. Verified that i had the black and white backwards!

Thanks


Don