Does anyone recognize this manifold pressure restrictor?

Hi

My friend noticed today that my manifold pressure reading on the my Dynon Skyview only seemed to be reading static pressure, with no change when changing the throttle setting.

We took the cowles off to have a look and the hoses all look good. There is a hose that runs from the manifold pressure port of the engine to the Dynon manifold pressure sensor with two tubes running to each of the two P-Mag electronic ignition unit. Gently sucking the hose showed an immediate change of the reading on the Skyview. So the sensor reads.

We then looked at the manifold pressure restrictor and took this off the engine. It was all black with carbon so we suspected a blocked hole. I took the parts home and cleaned it as much as possible, but unless the hole is absolutely minuscule, it almost looks like the unit is a blank and there is no hole on it?

Does anyone recognize the parts and can tell me what it is. Also, could it be a blank and if so, how would the pressure be measured? Any alternatives to replace this with?

Thanks!

R

Just drill a #50 hole on that and it should be good to go.

Looks like someone forgot to drill the restrictor hole.

baffle?

I don't recognize that part, but is there perhaps a restriction hole in the female fitting, and the plug in the male fitting is a baffle that is supposed to allow flow around a small gap at its edge? It is hard to see from the photo if this is the case. Assume you have blown through the fitting with compressed air while cleaning it?

I bought a .040” and then a .015” restrictor fitting from McMaster Carr (they call them gauge vibration dampers) to settle the rapid fluctuations displayed on my EMS D10 for MAP. Still had the fluctuations so I finally bought a .004” restrictor fitting that works. My MAP now stays settled and only takes a couple seconds with throttle change to register the steady new value.

The .004 hole is tiny, almost not visible. I can see where it would easily be covered over or clogged by some tiny debris. Maybe an air blast, soak in MEK, something like that to uncover it? Seems unlikely that a solid, no-hole fitting would be installed in the MAP hose. Who sells such a thing and for what purpose?

Hoppes #9 will clean up that brass restrictor better than any solvent out there.

Westerhuis said:

Hi

My friend noticed today that my manifold pressure reading on the my Dynon Skyview only seemed to be reading static pressure, with no change when changing the throttle setting.

We took the cowles off to have a look and the hoses all look good. There is a hose that runs from the manifold pressure port of the engine to the Dynon manifold pressure sensor with two tubes running to each of the two P-Mag electronic ignition unit. Gently sucking the hose showed an immediate change of the reading on the Skyview. So the sensor reads.

We then looked at the manifold pressure restrictor and took this off the engine. It was all black with carbon so we suspected a blocked hole. I took the parts home and cleaned it as much as possible, but unless the hole is absolutely minuscule, it almost looks like the unit is a blank and there is no hole on it?

Does anyone recognize the parts and can tell me what it is. Also, could it be a blank and if so, how would the pressure be measured? Any alternatives to replace this with?

Thanks!

R

Click to expand...

It looks like the McMAster Gauge Vibration Damper. I have them of various sizes on my MP, Fuel Pressure, and Oil Pressure sensor lines.

https://www.mcmaster.com/gauge-vibration-dampers

The hole is there, but TINY.

Tom

If you expand the picture, is the arrow perhaps pointing to the hole?

Yep-----

Tom

Thanks everyone - When I looked for some example restictors online they all seemed to have a bigger orifice. But mine was indeed tiny (0.004" I suspect) and I managed to unblock it with a needle.

Thanks and another lesson learned.