Weird problem - activating horn causes

IG.

Registered
I added extra horn yesterday (electric, FIAM) additionally to the stocker. It's loud as hell, and the two of them sounding together create sort of reverberating sound, very loud and annoying - which is good.

Anyway, when the igintion is ON (but engine is not running), when I press the horn button for longer than like 0.1 sec, I hear the fuel pump re-starts. You know that sound you hear when you first turn the ignition key (high pitched, but quiet sound which dissapears in a few sec).

Nothing changes on instrument panel - neither lights, nor gauges.

When the bike idles, and I use the horn. I beat the hell out of the horn button, but nothing happens. Even if the fuel pump re-starts, I cannot hear because of the engine noise. Here is a side question: if we assume for a moment that the fuel pump re-starts, would that cause the engine to die?

It does not seem to be an electrical issue, because the horn draws much less power than let's say both headlights turned on at the same time. I have a permanent Volt-meter installed, and when I press the horn button, the voltage hardly drops. However, when I turn both head lights on at the same time, the voltage drop is noticable, but nothing happens with the fuel pump.

The only idea I have at the moment is the fact that the sound frequency of the new horn causes resonance with parts of fuel pump relay, thus cause momentary loss of power to the fuel pump.

More experimenting is in order, but I would like to know what you guys/gals think about it.

Igor
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The only idea I have at the moment is the fact that the sound frequency of the new horn causes resonance with parts of fuel pump relay, thus cause momentary loss of power to the fuel pump.

More experimenting is in order, but I would like to know what you guys/gals think about it.

Igor
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Bump!

My reaction exactly. What the...
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Just spoke with my co-worker, and he suggested that this could be RF interference. That makes more sense. The way horns work, they break and re-connect electrical circuit hundreds of times per second, creating sparks and emitting plenty of RF which could interfere with ECM. The horn wiring serves as antenna. So, ECM goes a little crazy, and re-powers fuel pump.



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