No Fuel Pressure Reading

[PhantomPholly]

Had my first flight the other day (D180/HS34) and most everything seems to be working with one exception - Fuel Pressure reads 0 under all conditions.

Blowing into the sensor will yield up to +0.5psi. The sensor is inserted into the fuel injection distributor right where it would be on a twin Comanche (same IO-320B1A engine). Undo one of the output lines and turn on the electric boost pump, and you can get a FF of up to 32gph out of the sucker (and we have verified that the FF is at least close to accurate).

Any thoughts?

 

[dynonsupport]

If I remember off the top of my head, that sensor has one post for the sensor wire. In addition to that connection, the case also needs to be grounded (to a ground common to the EMS ground). That would be my first check.

 

[PhantomPholly]

My mechanic thought of that, and put a dedicated ground strap to the sensor (just in case the sealant was insulating it at the threads).

Will check the ground differential between the block and the avionics buss, but since they are connected by the same ground cable that travels back to the battery I'm guessing there is not much measurable difference between the two.

 

[PhantomPholly]

Problem solved:

1. The thread sealant did in fact prevent a good ground to the motor.
2. There being no convenient place to attach a ground strap, a bare wire was connected to the body held in place only by a zip-tie. Connection was not tight enough
3. Will switch to a metal hose clamp and solder the wire to the clamp.

Guys - this is a pretty annoying issue. Any chance you could come up with a better "book answer" to this one? Do you have any input to the manufacturer such that you could ask them to ad a grounding post?

 

[dynonsupport]

We don't have that kind of clout. Even at our high order quantities (relative to our industry competitors), we're small potatoes for a pressure sensor.

We do look for different pressure sensor options from time to time, but, unfortunately, finding ones that are cost effective is tough.

 

[edemalleray]

Hello !
I have exactly the same problem !! no reading at all. While my steam gauge gives a correct reading (translated into FF), the Dynon reads nothing. I will check that the casing is correctly grounded. It has been grounded so far with a wire running from the engine and held tight on the casing of the sensor by the clamp.
If you could send pictures of something that works , that would be helpful for me to fix the issue

 

[jakej]

[td]It has been grounded so far with a wire running from the engine and held tight on the casing of the sensor by the clamp.[/td]

Atar

That should work however I'd use one of the ground wires direct from the Dynon - always has worked for me  

Jake J