JPI 900 fuel tank question

[Godfather]

My IA is in the process of installing a 900 on my 2001 ovation. This unit will replace the moritz system.  Does anyone know if the JPI is attached with a new wire run to the tank sensors or use the current tap that runs through the control module?  Thanks!

[epsalant]

My IA is in the process of installing a 900 on my 2001 ovation. This unit will replace the moritz system.  Does anyone know if the JPI is attached with a new wire run to the tank sensors or use the current tap that runs through the control module?  Thanks!

I don't think JPI connects to tanks at all. You input fuel volume (e.g. In my 201 I tell the JPI that I have 64-full--or 50 gallons--tabbed--and it calculates fuel flow, and fuel remaining by subtracting fuel used from the value I input.

That's why you have to calibrate it by setting k factor after each fillup initially. Once you get it set it will be very accurate. Read the manual or p.m. ne, we could talk...

Sent from my XT1254 using Tapatalk

[Marauder]

My IA is in the process of installing a 900 on my 2001 ovation. This unit will replace the moritz system.  Does anyone know if the JPI is attached with a new wire run to the tank sensors or use the current tap that runs through the control module?  Thanks!

They use the leads that come from the fuel senders and go to your factory gauges.


Sent from my iPad using Tapatalk Pro

[Marauder]

I don't think JPI connects to tanks at all. You input fuel volume (e.g. In my 201 I tell the JPI that I have 64-full--or 50 gallons--tabbed--and it calculates fuel flow, and fuel remaining by subtracting fuel used from the value I input.

That's why you have to calibrate it by setting k factor after each fillup initially. Once you get it set it will be very accurate. Read the manual or p.m. ne, we could talk...

Sent from my XT1254 using Tapatalk

The fuel levels are determined by the fuel senders. The fuel calculation you are talking about is the estimated fuel usage determined by the fuel transducer and reported by the JPI.

The k factor calibrates the transducer to more accurately report the total fuel burned. The way you determine the new k factor is to compare the actual fuel usage against what the JPI is reporting and adjusting accordingly.


Sent from my iPad using Tapatalk Pro

[Marauder]

One other point on the "fuel used" versus fuel level the JPI "gauges" report. If the fuel used is off versus what the fuel quantity being reported, you will get an error message call "fuel level mismatch". Ask me how I know


Sent from my iPad using Tapatalk Pro

[epsalant]

One other point on the "fuel used" versus fuel level the JPI "gauges" report. If the fuel used is off versus what the fuel quantity being reported, you will get an error message call "fuel level mismatch". Ask me how I know


Sent from my iPad using Tapatalk Pro

I'm sorry. My comments were for the JPI 730...I believe Marauder is correct for your unit. What I said about calibrating is true...

Sent from my XT1254 using Tapatalk

[Oscar Avalle]

Unless you have a digital sender, fuel quantities are not very precise. But if you cross check with used fuel it gives you a good sense of how much is left.
Oscar


Sent from my iPhone using Tapatalk

[Bob_Belville]

When my 930 was installed the resistance senders were sent to Airparts of Lock Haven and were "rebuilt". They're reasonably accurate though the FF accumulated is far more accurate if you note how much you've used from each side when you switch tanks. 

[Marauder]

When my 930 was installed the resistance senders were sent to Airparts of Lock Haven and were "rebuilt". They're reasonably accurate though the FF accumulated is far more accurate if you note how much you've used from each side when you switch tanks. 

I've got my fuel totalizer dialed into a few tenths of a gallon on fillups. The gauges are still rough estimates, close but no where near what the totalizer provides.


Sent from my iPad using Tapatalk Pro

[Bob_Belville]

6 minutes ago, Marauder said:

 

I've got my fuel totalizer dialed into a few tenths of a gallon on fillups. The gauges are still rough estimates, close but no where near what the totalizer provides.


Sent from my iPad using Tapatalk Pro

 

Yeah, I keep a spreadsheet. The last 11 flights totaled 242.5 on the FF accumulator. The total of fill ups was. 243.2. That's about 0.1 gallon difference per fill up.

[Godfather]

On 3/3/2017 at 5:11 PM, epsalant said:

I don't think JPI connects to tanks at all. You input fuel volume (e.g. In my 201 I tell the JPI that I have 64-full--or 50 gallons--tabbed--and it calculates fuel flow, and fuel remaining by subtracting fuel used from the value I input.

That's why you have to calibrate it by setting k factor after each fillup initially. Once you get it set it will be very accurate. Read the manual or p.m. ne, we could talk...

Sent from my XT1254 using Tapatalk
 

I have been using the fuel flow method for years and it works very well. This unit will replace my primary fuel gauges and with hopefully work as well as my moritz gauges. 

On 3/3/2017 at 5:18 PM, Marauder said:

 

They use the leads that come from the fuel senders and go to your factory gauges.


Sent from my iPad using Tapatalk Pro

 

That is what my IA was planning on. However, there is a fuel computer unit in between the gauges and the fuel sensors. 

4 hours ago, Oscar Avalle said:

Unless you have a digital sender, fuel quantities are not very precise. But if you cross check with used fuel it gives you a good sense of how much is left.
Oscar


Sent from my iPhone using Tapatalk

The Moritz gauges were wonderful and very accurate during flight.  Hate to see them go, hope the JPI can work as well. 

4 hours ago, Bob_Belville said:

When my 930 was installed the resistance senders were sent to Airparts of Lock Haven and were "rebuilt". They're reasonably accurate though the FF accumulated is far more accurate if you note how much you've used from each side when you switch tanks. 

JPI said we are good to go with the fuel sensors in he Ovation 2. 

[Bob_Belville]

3 minutes ago, Godfather said:

I have been using the fuel flow method for years and it works very well. This unit will replace my primary fuel gauges and with hopefully work as well as my moritz gauges. 

That is what my IA was planning on. However, there is a fuel computer unit in between the gauges and the fuel sensors. 

The Moritz gauges were wonderful and very accurate during flight.  Hate to see them go, hope the JPI can work as well. 

JPI said we are good to go with the fuel sensors in he Ovation 2. 

The JPI will be as good as the various sensors including the fuel level sensors. And of course you'll have all that data saved for analysis.

[carusoam]

If your fuel level system is important to you...

Consider getting the digital fuel level sensors to go with your JPI.

It would make the ultimate digital belt and suspenders approach to knowing your fuel left on board or to the destination.

it wouldn't make a lot of technical or financial sense to retain the old analog stuff...

About me... my O1 uses FF/accumulator.  The back-up is a completely imprecise set of analog needles on the instrument panel....

Continue to go digital in all aspects...

PP thoughts only. Not a mechanic.

Best regards,

-a-

[Godfather]

26 minutes ago, carusoam said:

If your fuel level system is important to you...

Consider getting the digital fuel level sensors to go with your JPI.

It would make the ultimate digital belt and suspenders approach to knowing your fuel left on board or to the destination.

it wouldn't make a lot of technical or financial sense to retain the old analog stuff...

About me... my O1 uses FF/accumulator.  The back-up is a completely imprecise set of analog needles on the instrument panel....

Continue to go digital in all aspects...

PP thoughts only. Not a mechanic.

Best regards,

-a-

The Moritz factory system is digital I think although the adjustments are definitely analog. 

[carusoam]

The moritz system is nice until it decides that it needs service.

It fell victim to the oft fought war between digital and analog displays.  Moritz gave both...

JPI handles the battle by using a digital display to give graphs and numbers.

The JPI is further improved by attaching the latest digital, and more accurate, fuel level sensors to it.

I guess the brain likes data in two forms. Quick, easily scannable data, and exact, 'do I have enough gas to get home?' numbers.

Unfortunately Moritz has left the market.  It would be really cool if Mooney could get a run of replacement parts built or service the failed ones....

I don't have a Moritz display.  Just things I learned about on MS...

I am amazed that the Moritz display maintained the push button for voltage display, instead of giving a seventh, always on display of volts... 

Best regards,

-a-

Edited March 5, 2017 by carusoam