Can anyone identify the external ports on 85-88 throttle body? I know that the ones on the IAC housing are for coolant, and Im not using them. But there is one larger one on the pass side that I dont know about, and one small fitting on the bottom driver side? Can I run them un blocked ? or Do I need to do some thing with them? Thanks in advance

 

The top left on the passenger side goes to the rubber grommet on the passenger side valve cover.

The small bottom port goes to the EGR switch. The EGR switch is under the driver front corner of the Throttle body. That small port underneath the Throttle body is the vacuum supply to the switch, and it's a "U" shaped section of hard vacuum line that slides over it. The other end slides into a rubber hole on the EGR switch.

 

I have heard of taking the coolant away from thr throttle body , just curious as to why ? BTW 86pacer very nice car!

 

What would I do if I am not running the egr system? Im really not sure on the coolant, But I thought GM did that to keep from freezing in cold weather? No worry of that in July

 

Yes. Just cap off the ports you are not using with some rubber caps like these of the correct size:



Hardware stores and some parts stores carry sets of different sizes, or individually. You don't need to plug the coolant ones on the throttle body if you are not using those. Just the vacuum ones.


Thanks. GM chose to circulate hot coolant through our throttle bodies to prevent icing from forming on the throttle flaps in cold weather. The GM shop manual even says this. It's believed that this causes the incoming air going through the throttle body into the engine to get hot or hotter. Cold air is better for performance obviously. So bypassing eliminates this heat, thus in theory keeps the air colder going in.

Then there are those who say the air travels through there too fast for it to be subjected to heating. And others believe that most all of us will never be in a place cold enough to cause icing anyway and don't need coolant in our throttle bodies. I did it because it's almost free, and makes it easier to remove and service my throttle body when needed without introducing air into my coolant system, and spilling coolant. It also eliminates two potential leak points if you bypass the way I described below.

To do the coolant bypass, just undo the two coolant lines at the bottom of the throttle body. One is on the side, and other other on the front. Then to go your local parts store, and buy a long piece of hose (about 3 feet and cut to size) of the same diameter, but with a 90 degree bend on one end. You need this bend because a straight hose will just pinch off with the turn you need to make there.

Now all you do is connect this new hose from the hard metal coolant line on the passenger side, directly to the fitting on the front base of the intake manifold below the throttle body, "bypassing" the throttle body altogether.

 

I thought the smaller one on the right was for the CCP, EGR goes into the intake manifold.

 

What's CCP?

 

Youre kiddin me arent ya? Charcol Canister Purge system