JPI 900 Manifold Pressure Problem

[EDNR-Cruiser]

I am still waiting for my snubber... - it did arrive in Germany in the meantime but my dealer will keep it until I come and pick it up or the German Post stops striking...

I wonder now if the snubber is really needed and if JPI know what they are doing? I bought my 900 in April and had it installed in May. When I complained I had to send them some data to prove that I'm not nuts and then they sent the snubber. Wished they had sent a firmware upgrade... - so I will keep flying with a MAP display jumping around like crazy... 

[Marauder]

I am still waiting for my snubber... - it did arrive in Germany in the meantime but my dealer will keep it until I come and pick it up or the German Post stops striking...

I wonder now if the snubber is really needed and if JPI know what they are doing? I bought my 900 in April and had it installed in May. When I complained I had to send them some data to prove that I'm not nuts and then they sent the snubber. Wished they had sent a firmware upgrade... - so I will keep flying with a MAP display jumping around like crazy...

For those dealing with this issue, how much variability are you seeing? Mine is oscillating about 0.5 psi.

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[Lood]

Same here. Probably not a big deal but I found it extremely annoying.

[Marauder]

Same here. Probably not a big deal but I found it extremely annoying.

Me too. Considering the 830 MP was rock solid.

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[N601RX]

Here is my MP before and after.  My 830 did not have the noise.  I think the difference may be in how the sensor is mounted.  With the 900 it is connected to the intake port with a short piece of hose so it sees every pressure pulse in the intake pipe.  With the 830 it is mounted on the back of the mechanical factory gauge further away from the pulses.  The mechanical factory gauge also "stores" some volume of air inside it which in addition to the longer hose may dampen the pulses some.

It seems like JPI should have been able to filter or average the noise out.

[Marauder]

Here is my MP before and after. My 830 did not have the noise. I think the difference may be in how the sensor is mounted. With the 900 it is connected to the intake port with a short piece of hose so it sees every pressure pulse in the intake pipe. With the 830 it is mounted on the back of the mechanical factory gauge further away from the pulses. The mechanical factory gauge also "stores" some volume of air inside it which in addition to the longer hose may dampen the pulses some.

It seems like JPI should have been able to filter or average the noise out.

Thanks for sharing this. Your data (if I'm reading the scale correctly) shows about 1 inch of deviation. Mine is a little less but definitely a very noticeable fluctuation.

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[Ratherbflying]

Recreating this lost post.

How old is your unit? Mine was built in February. Wonder when they applied the firmware.

Mine was built in February as well. The loaner they sent me in June was 1200 serial numbers newer than my unit, so they must be selling a ton of these.

The software can be updated in the field on the 900's. They emailed me both new software, new config file, and directions last year to install it.

This doesn't appear to be how they are doing this now. I suspect that since this is a Primary instrument they figured out that they needed to tightly control the firmware. It's a pain in the ass but I guess once it is working I won't have to touch the software again.

[N601RX]

I just looked back in my emails and it was last October when they sent me the new Software, Config and CRC files.  The config files were specific to my units serial number.  The procedure was very easy, Hold button 1&2 down while powering up and then follow the directions on the Apploader screen.  If my unit only needed a software update I would press the issue, tell them you know that they have emailed new software to other customers and see if they would email it to me. I only needed the software update because of a known bug that prevented one of the gauges from displaying properly when in the vertical orientation. They quickly told me it was a known issue and they would email me the files to fix it without me even asking for them.   I've heard several others say that they have had to send their unit back for a software update.  This makes me think they may be doing more than a software update to some units don't want to publicize it. It cost them almost nothing to email out a new file, but would be very expensive for them to config and ship out loaners and then return the original units. 

[Marauder]

I just looked back in my emails and it was last October when they sent me the new Software, Config and CRC files. The config files were specific to my units serial number. The procedure was very easy, Hold button 1&2 down while powering up and then follow the directions on the Apploader screen. If my unit only needed a software update I would press the issue, tell them you know that they have emailed new software to other customers and see if they would email it to me. I only needed the software update because of a known bug that prevented one of the gauges from displaying properly when in the vertical orientation. They quickly told me it was a known issue and they would email me the files to fix it without me even asking for them. I've heard several others say that they have had to send their unit back for a software update. This makes me think they may be doing more than a software update to some units don't want to publicize it. It cost them almost nothing to email out a new file, but would be very expensive for them to config and ship out loaners and then return the original units.

Update: JPI wants me to send the unit back to correct the manifold fluctuation problem. Will update the update when I get it back.

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[Ratherbflying]

I finally got around to snapping a picture of my panel with the EDM 900 installed. The right side of the panel is empty so nothing to see there.

 

What an improvement.

[Marauder]

Another update. Unit is back from JPI with the MP firmware update. Ferrite installed to fix the GTN open squelch issue and unit will be installed back in the plane tomorrow. Will let everyone know if it fixes the problem.

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[Marauder]

Another update: the manifold pressure is still fluctuating a bit, but better than before. I didn't notice this before, but there are some changes that the new firmware is showing.

Before:

After

It looks like the hottest cylinder and EGT temps now have a colored background. As well, the fuel levels in the tanks are now shown on graduated scale gauges.

It also looks like there are new colors and gauge marking for MP & RPM as well

Is this what everyone is seeing on the newer version of the JPI 900?

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[N601RX]

What is the latest firmware rev?

[Marauder]

What is the latest firmware rev?

Not sure. Will look it up when I get over to the airport.

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[EDNR-Cruiser]

You should at least calibrate your HP settings... - 105% looks nice but is not realistic...  ;-)

[Ratherbflying]

A

Is this what everyone is seeing on the newer version of the JPI 900?

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Yessir.

What is the latest firmware rev?

My firmware level is 1.30.1018

[carusoam]

Could be realistic when atmospheric pressure goes above 29.92"?

Or the OAT goes negative...

Essentially, when flying below 0’ density altitude, Full throttle and Max rpm, HP should show greater than 100%...

I don't see OAT on this particular photo.

The calculation that JPI uses leaves a couple of questions as well. ROP vs LOP...

Best regards,

-a-

[Ratherbflying]

I don't see OAT on this particular photo.

-a-

OAT was 72, displayed below and to the right side of the tach.

[Marauder]

You should at least calibrate your HP settings... - 105% looks nice but is not realistic... ;-)

Yeah, it looks like some of my settings were erased when they did their MP firmware update.

[Shadrach]

Normally I would use the phrase "You snooze, you lose". But in your case "You chop, you stink" and by the way, you still lose

I have been busy making zucchini chips using my dehydrator. That particular vegetable has quite a bit of flexibility to it.

Finished another batch of dehydrated chives last week. Harvesting scallions and leeks soon. Yummy.

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Zucchini Pasta is fantastic!

 

http://www.gefu.us/#!store/cn79/products/spirelli-spiral-cutter

[Marauder]

Zucchini Pasta is fantastic!

http://www.gefu.us/#!store/cn79/products/spirelli-spiral-cutter

My wife is in love with zucchini. I'm sure it is a size thing, but she can't get enough of it. She keeps going out to the garden and checking to see if they are big enough

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[DXB]

On 7/28/2015 at 8:59 PM, Marauder said:

My wife is in love with zucchini. I'm sure it is a size thing, but she can't get enough of it. She keeps going out to the garden and checking to see if they are big enough

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I'm reviving this fun thread   - I've had my JPI900 about 5 months, and I like it on the whole.   But I have one major beef with it.   My MP bounces by about 0.5" constantly- no big deal, just an annoying distraction in my visual field.  JPI supposedly gave my dealer the firmware fix, but it made no difference at all.  Grrr.   It's particularly annoying because there's no numbers on the analog arc, so no way to set by roughly eyeballing it - the single worst part of the design.  

I'm wishing I kept my analog MP/RPM gauges - particularly since the JPI partially crashed once in flight before the firmware upgrade (lost all engine readings but kept fuel level and a couple other things) - it rebooted after about 30 seconds, just as I was about to pull the breaker to reset.  No way I'm sending back to JPI currently unless it recurs - this would ground me as it's primary.

Should I install a "snubber"?   Should I quit bitching because 0.5" of oscillation is normal?   Should I make some zucchini instead?  Maybe this would mellow me out.

[Andy95W]

23 minutes ago, DXB said:

   Should I make some zucchini instead?  Maybe this would mellow me out.

Zucchini?  How does that work, Dev?  Do you have to smoke it?

[DXB]

5 minutes ago, N1395W said:

Zucchini?  How does that work, Dev?  Do you have to smoke it?

Never tried - or at least I didnt inhale.  Just a weak attempt at humor based on this thread previously drifting into sharing zucchini recipies 

[kortopates]

On 7/28/2015 at 8:59 PM, Marauder said: My wife is in love with zucchini. I'm sure it is a size thing, but she can't get enough of it. She keeps going out to the garden and checking to see if they are big enough

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I'm reviving this fun thread   - I've had my JPI900 about 5 months, and I like it on the whole.   But I have one major beef with it.   My MP bounces by about 0.5" constantly- no big deal, just an annoying distraction in my visual field.  JPI supposedly gave my dealer the firmware fix, but it made no difference at all.  Grrr.   It's particularly annoying because there's no numbers on the analog arc, so no way to set by roughly eyeballing it - the single worst part of the design.  

I'm wishing I kept my analog MP/RPM gauges - particularly since the JPI partially crashed once in flight before the firmware upgrade (lost all engine readings but kept fuel level and a couple other things) - it rebooted after about 30 seconds, just as I was about to pull the breaker to reset.  No way I'm sending back to JPI currently unless it recurs - this would ground me as it's primary.

Should I install a "snubber"?   Should I quit bitching because 0.5" of oscillation is normal?   Should I make some zucchini instead?  Maybe this would mellow me out.

For sure a snubber will fix it. But I have seen their firmware update finally resolve the problem with many of our clients. They have released several firmware updates before fixing many so I would encourage you to contact their tech support and see if they have a newer update than what you now have. If they say no, it doesn't hurt to ask them for a snubber. They use to provide them but they are now bent on fixing this in s/w.

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