Just going through some things with an AU VCT engine conversion into an XF ute. I have got it running using a J3 chip on the AU ECU, AU engine loom and a few other bits and pieces.

I am now working on the Broad Band manifold and how to get that working (switching between its two states of operation). Can anyone tell me how it works? There is a vacuum line coming from the broad band manifold actuator at the front of the manifold but I don't have anything else.

The way I think it works is there should be an electrical solenoid which is earthed at the ECU via pin 98. This solenoid lets full manifold vacuum pass to the BBM actuator at above 3800 RPM.

Is this right?

Thanks in advance.

yes there is normally a solenoid that allows the switch over at 3800rpm, in an au its behind the windscreen washer bottle.
the way it works is, it has manifold vacuum to the diaphragm via the solenoid when the engine is running, the solenoid is energised and it holds the vacuum to the diaphragm until 3800 rpm where the ecu switches the solenoid off releasing it..

As Troy indicated... As soon as you start the car and it builds vacuum the butterflies change state to long runners... Once you rev it past 3800 rpm the vacuum in the runner diaphragm vents to the atmosphere and a spring opens the butterflies allowing the short runner path to be used...

Cheers,
Tim

Ok, appreciate the help with that. Makes sense, a trip to the wrecker should have that sorted. Only thing I'm not sure of though is on the wiring diagram it is showing a BBM Sensor. What is that sensor for and what is its input? I might be assuming wrongly that it stands for Broad Band Manifold "sensor"?

Thanks again for any input.