Replace Manifold Pressure Sensor?

M

Maccool

New Member
Joined
Dec 24, 2020
Messages
15
Van's RV-9A with IO-320-D1A, AFS5400 EFIS on SV-EMS. I'm getting erroneous manifold pressure readings, no leaks in the tubing connections. What sensor would I use to replace the presumably defective one?
 
Depends entirely on which one is wired into the EMS. Assuming here that you did not build the airplane... Pull the cowling and look, most likely on the firewall, for some transducers with lines running in one end and wires out the other - those will be your suspects. You'll find manifold pressure, oil pressure, fuel pressure, usually grouped in one area.

You can, of course, replace it with an entirely different type - but then you'll need to adjust the Dynon settings to recognize the new type. Replacing like-for-like will get you right back in the air.
 
The MAP sensor is apparently on the cockpit side of the firewall and I haven't seen it yet. I was hoping it would be a standard Kavlico part number as Van's or Advanced Flight might have used back in the day. As you surmised, I didn't build the airplane. I did install the AFS 5400 and its SV-EMS, but that was simply re-pinning the EMS, never saw the sensor. The old version sensor was an AFS 41400, new version (according to AFS install manual 3/2023) is an AFS 41401. But it appears that this 41401 MAP sensor was part of Kavlico's sensor-leak problem from 2020 and replacement was recommended with something from the 255 series.

I guess I'll have to try to wiggle down there to find it, if for no other reason to see what kind of electrical connector pack is attached as well as to see what sensor the OB actually used. Thanks for your help though...
 
I had same issue. Pulled the sensor, looked up the part number and for $15 got a replacement off Amazon. It's typically a general auto parts MAP sensor.
 
It turned out to be a leak in the pressure tubing at the T where the line to the emags came off. Fixed that and that solved the problem
 
I've had to replace that hose firewall forward due to degradation of that hose. Pretty cheap fix from NAPA !
 
Italiancowboy said:
I've had to replace that hose firewall forward due to degradation of that hose. Pretty cheap fix from NAPA !
Click to expand...
I agree, that would be simple. In this case the main tubing was OK...the tear was in the 1/4" silicone emag tubing right at the T-connector. The original install was sliding that 1/8 inch mag tubing over a 1/4 inch T-connector. I suspect that it got torn when the mags were pulled for bearing inspection at the recent condition inspection.

1788022112616.jpeg
 
Italiancowboy said:
Might be good preventative maintenance to replace the hose since you've got it apart . . . .
Click to expand...
Yes, hoses are always something to watch in the hot under-cowl environment. Fortunately these are readily accessible and in good shape. I did replace the 1/4x1/4x1/4 T-connector with a 1/4x1/8x1/4 in order to take stress off the 1/8 inch emag hose. Solved the immediate problem.
 
You must log in or register to reply here.
Back
Top