MoTeC Global Forum

I have fitted an GM LS2 throttle body to my M800. When it is activated and the throttle is moving there is a high pitched squeal coming from the throttle body. Not only is it annoying but I can not help but think it will shorten the life of the throttle body. If the throttle blade is let sit still for a few seconds the throttle returns to its rest position and the noise stops. Start moving the throttle pedal and the noise restarts. I have confirmed that it is coming from the TB. Has anybody else had this happen to them ? Is there a way to fix it ? Or is the TB just defective.

Thank You

Whats the frequency set to?
functions>drive by wire>setup>frequency

Motec advised settings should be used for all DBW applications.

Any DBW motors I know of whistle whilst active.
It's normal as far as I know.

Per the Motec tech sheet. For that throttle body it is 8,000 Hz. In fact all the GM TBs listed are 8,000 Hz. For reference the remaining parameters are:

PG 120
IG 80
DG 120
Period 1
Dead Band 0.3
FF 10
N Clamp -20
user
Freq 8000
Motor Volts 14

It is normal to hear a high frequency moise from the DBW motor when it is opperating and when it is stationary until it goes in to auto shut down. So what you are describing is normal opperation. The noise should not be very loud though and you should not be able to hear it over the sound of the engine when it is running. If it is loud and you have the correct settings in the ECU there may be something wrong with the DBW motor itself.

My Bosch also runs at 8000 Hz and while it can be heard it's not loud enough to hear over a running engine.

I only asked in case the op had gone away from the recomended settings and that was the cause of his whine.

The noise I am hearing certainly can not be heard over the engine. So I gather all is well. Thank you very much for your responses.