# Electric motor/servo noise minutes after SAI stops



## Emsworthy

Sorry, in question mode today. 
150 Roadster. On a cold start the usual SAI pump runs, is very audible and pushes idle to circa 1200 rpm. After a short time this stops and the revs drop to a stable 850ish and all is quiet. 2-3 minutes after this there is another motor/servo that kicks in for 10 seconds or so, it must draw a fair bit of current as the engine note changes and the interior lights dim. This has a different sound to the SAI, a bit like the sound of the undercarriage coming up on an aircraft after take-off!
Is this normal? Any clues as to what it is?


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## Outdoorstevie

Have you got the aircon on or off ? this is heavy on the current so the engine may struggle especially if the alternator isn’t in great condition to supply the current.

stevie


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## Emsworthy

Aircon is not functioning as it is low on gas so the compressor doesn’t run at all irrespective of the switch position. I ran the car from cold last night with the bonnet open to check it wasn’t the fans spinning up momentarily and it definitely isn’t the fans. Seemed to come from further back in the engine bay.


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