EDM 900 owners

[N601RX]

I was one of the earlier installers of a 900 system and had pulsation on both the manifold pressure and fuel pressure.  In reality both the fuel pressure and MP have natural occurring pulses in them every time the intake valve closes or the fuel pump cam rolls over.   It appears JPI doesn't have sufficient filtering on either of these signals for some engines and the sensors are just reporting what they are seeing at that instant it time.   I posted graphs of both before and after getting this resolved a few years ago.  McMaster sells stainless NPT fittings with orifices as small as .010".   If placed at the engine end of the hose they will remove the pulses nicely and also provide some level of safety if the hose ever came off or started leaking.

My thought on why JPI isn't always willing to offer these up immediately is because it is not part of their TSO or STC and they don't wont to open up a can of worms.

 

[MIm20c]

From talking with JPI on the phone and at airventure the owner is attentive and CS oriented. I also found one person that really knows his stuff, the “motor head” of the company, but I’m drawing a blank on his name. 

[Marauder]

From talking with JPI on the phone and at airventure the owner is attentive and CS oriented. I also found one person that really knows his stuff, the “motor head” of the company, but I’m drawing a blank on his name. 

Tim?


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[MIm20c]

12 minutes ago, Marauder said:

Tim?
 

 

 

I think so, it’s on the master list at home - the one or two people at each company that can get the job done not just waste my time. 

Edit:  the fact that I don’t have the list on my phone probably means I’m not on the short list for IT or data management where I work

[ArtVandelay]

This can easily be handled by software, take a reading every 0.1 secs, when it comes time to log it, just average the readings.

[wcb]

So, I have a JPI EDM 900 in the box (Just received the shipment).  I was going to have my A&P do the install but it is looking like I should have one of our guys Mooney guys that have gone through these issues do the install.  Anyone near Houston?????

[Oldguy]

8 hours ago, MIm20c said:

From talking with JPI on the phone and at airventure the owner is attentive and CS oriented. I also found one person that really knows his stuff, the “motor head” of the company, but I’m drawing a blank on his name. 

 

6 hours ago, Marauder said:

Tim?

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Tim Sullivan

[Stephen]

On 10/18/2017 at 11:53 PM, RLCarter said:

Not sure if this has been asked or not..... Has the issues  been there since the install, or have they popped up slowly over time? Is this an owner installation, owner assisted, or shop installed? 

Like that since first installed

[RLCarter]

57 minutes ago, Stephen said:

Like that since first installed

sure sounds like a grounding issue

[Stephen]

12 hours ago, RLCarter said:

sure sounds like a grounding issue

I think if i run new, dedicated grounds joining engine to airframe to instrument panel (per Anthony) and EDM to engine that should remove grounding as a variable. Ill do that next

[JoshMan]

On 10/17/2017 at 11:14 PM, Stephen said:

DXB  thanks for the intel....I posted a video of mine above .... is that what you were seeing?

 

Bob and Anthony thanks also. I'll ask JPI for a snubber. 

This is exactly what I am seeing.  I am also re-grounding next week.  Will let you know what I find.

 

Josh

[carusoam]

Somebody posted the voltages are tinier than tiny....

I called them millivolts, they pointed out that microvolts was a better description... a 10³ difference....

Clean connections amongst the grounds will be more important than usual.

With protection against oxidation where possible...?

PP thoughts only, not a mechanic...

 

Best regards,

-a-

[Stephen]

Just now, pmccand said:

Check the fuses and connections at the load resistor for your ammeter.  There are two thin wires (white and grey) that measure  reference voltage across the block that gives amp data. 

Thanks PMC, I will!

[Stephen]

On 10/27/2017 at 10:26 AM, pmccand said:

Check the fuses and connections at the load resistor for your ammeter.

Just an update. The ammeter problem was the inline fuses (installer didn't put them in) .... if they are out your EDM 900 Ampmeeter will read 0, 1 or 2 amps all the time, no matter the load. MP is by experimentation: The original EDM installer put a solid MP sensor line to replace the "defective" one with the hole. Hole was there by design. Replacing the line with a hole took about 40% of the 10ths reading volatility away so it swings a little more than half the range it did before. I think it needs the snubber... next project. 

[carusoam]

The calibrated breather hole keeps fuel from being sucked into the old mechanical gauge... during changes in MP...

taking the calibrated leak out (accidently) changes the pressure that the MP sensor sees... a lot... whole inches...

Sure it is going to dampen the MP signal...

JPI must have some decent installation instructions by now...

Good luck getting through all the funny requirements with the JPI...

jumpy signals, FL data, and squelch breaks come to mind...

Best regards,

-a-

[FloridaMan]

if your mp is fluctuating, have your A&P drill out an AN fitting inline and insert one of these. Works perfectly to stabilize the manifold pressure. 

[Stephen]

8 hours ago, Antares said:

if your mp is fluctuating, have your A&P drill out an AN fitting inline and insert one of these. Works perfectly to stabilize the manifold pressure. 

Thanks @Antares I called Tim at JPI and they are sending a snubber. I wondered if you couldn’t make a carb jet work or if when my snubber arrives if it wouldn’t look suspiciously like a jet ... I guess you answered that question.