912UL Not Getting Fuel

by Corey Bonnell in 912 / 914 Technical Questions 10 years ago

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Re: 912UL Not Getting Fuel

by Corey Bonnell » 10 years ago

Corey Bonnell

4 14 0

I'm about to ask my hangar neighbor to uncowl his Kappa (912 ULS) to reverse engineer his electrical.

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Re: 912UL Not Getting Fuel

by Corey Bonnell » 10 years ago

Corey Bonnell

4 14 0

FYI:

Engine is grounded.
Resistance across lighting coil - 0.1 Ohms
Resistance to ground - No reading.
Charging cable resistance (4.4 & 4.6 Ohms)
Trigger coil resistance (239 & 242 Ohms)
Primary ign coil resistance 0.4 Ohms

No spark.

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Re: 912UL Not Getting Fuel

by Rob Seaton » 10 years ago

Rob Seaton

3 1.32k 240

Sounds like ignition switches are not wired correctly.
-the ignition does not get power from the battery or regulator; it gets its power from 2 of the stator coils and is completely independent from the battery system.
-The ignition switch wires ground the modules to kill the spark. no voltage is to be connected in this system.
Do you have 12 volts going to the ignition switches? or maybe they are grounded when you are trying to start? if so that is the problem.
The ignition switches need to be un-grounded or, in other words, open-circuit for the engine to run. You can check this with a multi-meter: one probe connected to the ignition switch wire and the other to ground; with the ignition switches OFF you should have continuity to ground. With the ignition switches ON you should have no continuity in the system (infinite or open circuit reading)
Take a careful look again at the installation manual; it shows the ASM signal wires going to the start relay, these ASM wires do not use any power, it is only a signal so the modules know when you are engaging the starter so it can retard the ignition timing. You do not have to connect these wires to run the engine.

Thank you said by: Corey Bonnell

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Re: 912UL Not Getting Fuel

by Corey Bonnell » 10 years ago

Corey Bonnell

4 14 0

OK. Because I don't have a huge ego and I'd rather see other folks learn something, no matter how silly or seemingly stupid...

I always looked at the electrical schematics of the ignition switches as "open" circuits since they depicted the switches as "open" and this was the "off" condition of the engine.

NOT SO!

The depiction is the "open" circuit and "ON" condition of the engine. SO...I have since re-wired the ignition switches to the correct position for "off", meaning grounded or closed circuit, and "on", meaning not grounded or open circuit.

Several electrical depictions also have both ignition switches eventually going through one wire to ground, so in my haste I wired them so. This is an unsafe condition where if the one ground wire fails, both ignition units would ground causing engine stoppage. This has since been corrected.

BTW, we tried another start yesterday with correct switch positions. The engine did not start, but we got a few pops out of it and the plugs did have fuel on them. I probably flooded it. Will try again this weekend with some starter fluid to "help" it get out of its storage funk.

Thanks for the help. I'm learning more about this hunk of metal every day.
Corey

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Re: 912UL Not Getting Fuel

by Corey Bonnell » 10 years ago

Corey Bonnell

4 14 0

Oh, we also got the timing light to fire with the probe on the number 2 cylinder plug wire. Woooohoooo! We have a heartbeat!

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912UL Not Getting Fuel

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