GT40 Alarm Test

[Seabrad]

I was looking to function test the oil and temp sensors on my 1999 Pro Air GT40.

The check engine light on the dash illuminates when the key is turned until engine is running as usual but how is each sensor tested whilst running and will they send the engine into limp mode when activated.

I was also looking to install a small 12 volt siren into the circuit with the check engine light as an additional safety measure.

Appreciate any input on the tests above or if I should just trust that the check engine light will do its job if there’s an issue..



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[Peter6000]

Both the oil pressure and temp. sensor switch to ground on low oil pressure or over temp.
When Ignition is on and engine off there is no oil pressure therefore the oil pressure switch is switched to ground and the light is on.
You can put a wire from each sensor to ground to test the alarm.
If you do it with the engine running it should switch to limp mode I believe the idle RPM go up to 800 and it lowers the max rpm to 2000 or so.
If you add a horn keep and just parallel it to the light it will make noise as soon as you turn on ignition.
You could use the power from the fuel pump to run the horn. If you turn the ignition on the horn would go off for a second until fuel pressure is up and may for a short time when you actually start. But not if you sitting with ign. on.
The diagrams are in the ProBoss manual if you need one let me know.
Peter

[Seabrad]

Hi Peter,
Many thanks for your reply. I have been away with work the last few weeks but will test the sensors as per your suggestion and post the results back here.


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