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Odd question... Ralt causes engine MFL?



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f16pointyhead
PostPosted: Jul 02, 2009 - 12:00 PM Reply with quote Back to top
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Just curious if anyone has ever seen this... when RALT is turned on it causes an ENG001 MFL. if the engine data is downloaded no ENG001 mfl exists. It only happens when RALT is on?
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f16pointyhead
PostPosted: Jul 03, 2009 - 08:52 AM Reply with quote Back to top
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update to this.... the spider harness to the EDU can cause this problem
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That_Engine_Guy
PostPosted: Jul 03, 2009 - 05:28 PM Reply with quote Back to top
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f16pointyhead wrote:
Just curious if anyone has ever seen this... when RALT is turned on it causes an ENG001 MFL. if the engine data is downloaded no ENG001 mfl exists. It only happens when RALT is on?

You'll never download a "MUX" fault from an engine; the 001/002/003 MFLs are generated by the aircraft, not the engine. They indicate loss of communication between the aircraft and engine. (Signal A, signal B or both) Look at the fault code listings for the engines and you'll notice these do not have corresponding engine faults associated with them.

Simple pin-checks of the system per the engine FI should vindicate the motor in question. Troubleshoot with the applicable avionics FI after all engine connections have been ruled out.

Two Cents Since you say it only occurs when specific aircraft systems are energized, check that system's diagrams to see if it shares a common matrix with the engine communication circuit. I 'suspect' you have something grounding or shorting into the engine circuit through some bad wires or a connector. Always use the FIs and wiring diagrams for specific guidance.
"I read about it on F-16.net won't fly with QA or Safety!" Doh

All else fails check with your Technical Rep from LM, and GE/PW Cheers

f16pointyhead wrote:
update to this.... the spider harness to the EDU can cause this problem

Yes; faulty, dirty, loose or disconnected engine interface 'Spider' harnesses cause this due to loss of signal. Airframe/engine communications all run through this harness from the aircraft to the engine's monitoring system. (PW or GE)

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VarkVet
PostPosted: Jul 03, 2009 - 10:24 PM Reply with quote Back to top
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This may be old info but should still be relevant for 220’s

Like TEG always preaches … use the book!
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I don't dork around with Pratt powered Vipers too much anymore, but I believe you will get ENG Bus Fail if you start her in BATT



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cchief16
PostPosted: Jul 04, 2009 - 01:03 AM Reply with quote Back to top
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on GE129 you look for 132, 133, 134 MFL's which indicate MUX bus fails

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That_Engine_Guy
PostPosted: Jul 04, 2009 - 01:59 AM Reply with quote Back to top
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cchief16 wrote:
on GE129 you look for 132, 133, 134 MFL's which indicate MUX bus fails


Yes they also relate to MUX, on the PW too. (but less prevalent than the double-zeros)

Still not "EMS" generated. GE's can also receive 001, 002, 003

At least both sets of codes are in both FIs.

Starting in BATT can also result in the ENG100 (PW) for ignition system fail, even though the motor will light off when enough RPM brings the Stator Generator to life.

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