More throttle body puzzler Options

[lsintampa]

For all you 2.0 d-jet folks....

Look at your throttle body plate (the valve that closes over the TB opening).

Does your valve have NO hole in it, one small hole, or does it have a nut and bolt in the hole?

See three samples below. The third photo doesn't show the small hole plugged, but you get the idea. It is like the second with a nut and bolt plugging up the hole.

Bonus question:

What purpose does the hole serve and why is it closed on some TB's?

(IMG:style_emoticons/default/beer3.gif)

Thanks,

Len


PHOTO 1 NO HOLE:


PHOTO 2 SMALL HOLE:



PHOTO 3 HOLE PLUGGED - THIS PHOTO DOESN'T SHOW IT, BUT JUST IMAGINE THE HOLE IN PHOTO 2 IS PLUGGED WITH A SMALL BOLT AND NUT.

[914forme]

Hole could be placed on some of the TBs to reduce the chance of vacuum lock. In this condition there is an extreme amount of vacuum pressure on the backside of the plate, and a large pressure difference from that of the front side. When this happens, the throttle blade tends to want to stay in the closed position, due in large part to the intense vacuum pressure created by the engine.

Can be adjusted out with idle bypass, or even tipping the plate a small amount. Or drilling a small hole in the plate.

BTW, all my 73-74 2.0L had the hole, a 76 I owned did not.