Secondary Throttle Delete

OK Here is something I've been meaning to do for a long time. Delete the secondary throttle. Basically, in front of the 'real' throttle (which is normally closed) there is a secondary throttle, which is normally open. When the ASC detects unequal wheel speed front and rear, the ASC sends a signal to the actuator that closes the secondary throttle, thereby robbing power from the engine until the speeds match again.

When it is working well, it is rubbish, so we might as well delete the unneeded throttle all together to clean up the air flow path and shed a pound (or two?).

Oh, another bonus: the non-ASC boot (we are now putting in) is actually less expensive than the "correct" ASC boot, even though it is larger. So, if you own the car for a while, this can save some money!

This is a simple deal, and should take less than an hour to complete. You need:

5 mm allen wrench
10 mm deep socket
10 mm wrench (maybe)
Ratchet
1-inch extension
6 mm nut driver
Flat head Screw driver

"Boot" P/N 13 54 1 738 757
Hose clamp; 77-84 mm range (get it at BMW so it is not too wide like the US spec. ones are)
Another hose clamp, 25-35 mm range (I forgot to look at the size after I pulled it from the box)

Start by locating the traction control actuator. It should be next to the air box, on the inner fender.



Open the top and remove the cable. Remove it from the secondary throttle as well.


Here's what we're up against now:


Note: you need to dissconnect the secondary throttle position sensor as well, if you haven't yet.

Make sure the key is off (no need to dissconnect the battery) and unplug the air mass meter.


Next, use the nut driver to loosen the hose clamps on the intake boot (don't loose the one at the air mass meter end as it will be reused on the new boot ):


(continued...)