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120SX RPM outside of parameters

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120SX RPM outside of parameters

Old 07-04-2010, 01:19 PM
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kkling77
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Default 120SX RPM outside of parameters

During my second engine start today I received an "Acc. Slow" reading on the data terminal and the engine proceeded to shut down and commence the cooling process. The engine had spooled up to 28,500 before this happened. I let it cool down and started again with no issues. During the ensuing flight I noticed (or thought I did) a small trail of white smoke off the back of the plane for approximately .5 second while rolling out of a 1/2 cuban. The engine also seemed to "gurgle" a little for a brief moment a short time later. Sorry for the technical terminology, still new to the jet world. When I landed I checked the flight info on the data terminal and this is what I got:

Max Temp - 706 C (It has been rising the last 3 flights - started at 690, rose to 694, and now 706 this flight)
Avg Temp - 539 C

Start Temp - 632 C (have seen as high as 690)

Max RPM - 126500 (has always consistently been 123000 every other time I have checked; max RPM set for 123000)
Min RPM - 25700 (has always been around 32500 - 33000; idle RPM set for 33000)

Max Pump - 3.3
Avg Pump - 1.35
Min Pump - 0 (Never seen this before. Always been around .4)

The questions I have are:

1. What causes the "acceleration slow"? I realize it is because the acceleration was less than a pre-programmed value, but could it be something with the setup that can cause this or just an anomaly?
2. Should I be concerned about the rising max temps over the last couple of flights? The website states EGT range 580 - 690, but I can't find anything in the manual.
3. Why would the RPM's go out of Range on both the high and low side?
4. How could the minimum pump voltage be 0 at any point? Wouldn't that mean the pump was shut off?

Thanks for any help you may be able to provide.

Update:
I brought the airplane home and just tried to run it again. Start up was fine until it tried to "learn lo." It brought the RPM back to approximately 28000 then surged up to 39000 before eventually settling on 33000. I started to run the engine up and at approximately 65000 it surged pretty heavily, twice. I shut the engine down at that point and the data terminal started flashing something about the battery being low, the starter motor was acting erratically during the cool down process, and the temperature was fluctuating between 80 - 150 C. The battery was fully charged last night and I only had 2 flights on it today (2500 MAh LiPO). The battery voltage was reading 7.7 on the data terminal before engine start. Possibly a bad battery? Could a bad battery cause the erratic RPM during the "learn lo" process, engine surging, and RPM readings outside of the normal parameters as seen on the flight described above?
Old 08-08-2010, 08:37 PM
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kkling77
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Default RE: 120SX RPM outside of parameters

Another update:
Bought a new LiPO for the ECU and tried it today. As soon as I plugged the data terminal in it said "Battery Low" and was reading something like 1.8V. The fuel pump was making a "groaning" noise (for lack of a better term) even though I hadn't initiated a start sequence. Yes the battery was charged and balanced. Does anyone have any ideas? ECU, fuel pump gone south? I would appreciate any advice or insight.
Old 08-08-2010, 08:53 PM
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KC36330
 
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Default RE: 120SX RPM outside of parameters

did you observe the correct polarity of the new battery?
Old 08-09-2010, 07:01 AM
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kkling77
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Default RE: 120SX RPM outside of parameters

Yes, battery polarity is correct. This is now the second battery that has caused this message to be displayed.

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