JPI Service Pirep

[carusoam]

1 hour ago, Ragsf15e said:

Im just curious now, but why wouldn’t you put a snubber on the fuel or oil pressure line?  JPI told me some require it, and I’ve heard many people like having a “reducer” or “snubber at the start of the oil pressure line to limit the volume of oil that can escape quickly if there’s a leak leak later in the line?

Invite @ArtVandelay….

 

Gents,

Just to open the conversation on how snubbers work….

1) They are small devices mounted close to the transducer…

2) They only affect the reading the transducer is seeing…

3) They don’t get in the way of the fuel flow, or oil flow, or Airflow….  Because they are on a branch that is connected to those flows…

4) As far as being a limitation of leakage… great!  
 

5) It won’t be enough of a limit if a leak occurs…

6) The JPI and the sensors are more sensitive than the eyeball…   Some eyes are distracted by the numbers bouncing around…

7) If bouncing numbers are not a distraction… no snubbers are needed…

8) Same thing applies to mechanical gauges with bouncing needles…

+1 for creative marketing stories…

+1 for knowing how the snubber chops the physical noise from the measurement….

Best regards,

-a-

[Ragsf15e]

Just now, carusoam said:

Invite @ArtVandelay….

 

Gents,

Just to open the conversation on how snubbers work….

1) They are small devices mounted close to the transducer…

2) They only affect the reading the transducer is seeing…

3) They don’t get in the way of the fuel flow, or oil flow, or Airflow….  Because they are on a branch that is connected to those flows…

4) As far as being a limitation of leakage… great!  
 

5) It won’t be enough of a limit if a leak occurs…

+1 for creative marketing stories…

+1 for knowing how the snubber chops the physical noise from the measurement….

Best regards,

-a-

You can take a look at the other thread where Skates shares pictures of his snubber… it’s screwed directly into the engine (mp outlet), not the transducer.  The same thread, Doc talks about making one with a fitting, rivet and a very small hole.

[carusoam]

Just now, Ragsf15e said:

You can take a look at the other thread where Skates shares pictures of his snubber… it’s screwed directly into the engine (mp outlet), not the transducer.  The same thread, Doc talks about making one with a fitting, rivet and a very small hole.

Rags,

There seems to be a reason people may not want to use a snubber…

I was thinking people thought it would get in the way of the fluids and air going into the engine….

These measurements are taken from those flows without taking away from those flows…

And definitely, not causing a blockage to those flows…

Of course, it adds another connection that can fail or leak… but, not a fatal one…

 

I’m interested in why Tom has a snubber on one line, but doesn’t want to add a snubber on the other lines…

Could be as simple as the noise isn’t big enough to warrant a change… 

Best regards,

-a-

[ArtVandelay]

And definitely, not causing a blockage to those flows…
Of course, it adds another connection that can fail or leak… but, not a fatal one…
 
I’m interested in why Tom has a snubber on one line, but doesn’t want to add a snubber on the other lines…
Could be as simple as the noise isn’t big enough to warrant a change… 

Yes, it adds a (admittedly small) failure point to a vital system, and the variance is not noticeable during flight.
The MP was pretty bad and very noticeable because of the JPI graphics (RPM,MP large gauges), where as the oil/fuel pressure is small.

[Skates97]

I see very little fluctuations in my oil and fuel pressure. The only one I had bouncing around was the manifold pressure and it was very rhythmic/predictable. Adding the snubber to it steadied it out.

[Ragsf15e]

I installed a snubber for the MP and Oil Pressure.  It stopped the fluctuations which I think means they were actual or software fluctuations and not electromagnetic interference as JPI suggested.  I would think emi would continue regardless of a snubber.

[Baker Avionics]

On 6/23/2021 at 7:14 AM, 0TreeLemur said:

In May the Remote Alarm Light (RAL) on the JPI EDM900 engine monitor in our M20C stopped working.  I tested the LEDs using a multimeter and they seemed bad.   Turns out, I should have used the diode test function to overcome the forward bias voltage.  Live and learn.  Some here on MS pointed me to the source of a replacement RAL, which I tried to no effect.   I contacted JPI in late May and was given an RMA, but told not to send it in immediately.   I told them that we have a trip scheduled for June 25.

A week later I called JPI and they asked me to send it in.  In the box I included a request to fix the RAL problem and re-program to remove red RPM arc because we upgraded to a Top Prop that has no intermediate rpm restrictions on the M20C.   They received it on Friday, June 4.

Contacted them on Monday, June 14, to inquire about the status.  Was told that typical turnaround time is 1-2 weeks.

Contacted them on Friday, June 18, with a reminder that I have a trip scheduled for 25 June.  After checking with the service dept. my repair was moved to the front of the queue.  Later that day they e-mailed back and said it was done.  They had to replace one of the circuit boards.

No charge for the repair plus no charge for the first reprogramming request.   All I had to pay was shipping.  Received it yesterday and look forward to testing.

All told, a positive outcome.  I had a month between trips, and that was enough time.   Not fast.  Responsive service.   Communications essential.

Do you still need a RAL? I have one on the shelf I can get to you.

[0TreeLemur]

6 hours ago, Baker Avionics said:

Do you still need a RAL? I have one on the shelf I can get to you.

Thanks Greg, but  I bought one from Spruce.

Oddly enough, the original RAL was good.   I didn't test it correctly.  But, JPI replaced one of the boards in the EDM900 because it had a problem.  Funny thing is the original RAL wouldn't work with the repaired EDM..  The new RAL that I bought from Spruce worked fine with it.

Fred

[Oscar Avalle]

Do you still need a RAL? I have one on the shelf I can get to you.

I have the same problem. So if you have a snubber I would be interested.

Oscar


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