Hey guys, I want to do a vacuum test on my car because according to my haynes manual I can determine quit a bit about the condition of my motor with it. What hose going into the intake can I use to hook a vacuum gauge up to it for this kind of test. I am trying to see if I have an intake leak and according to haynes this is a good way to find it by the way the pressure reacts at idle. Anyone ever done this to there ls1 and can give me some pointers.

 

if your just checking for vacuum leaks its pretty easy to do by hand

there are 3 holes on the back of the intake manifold, 1 for break booster, 1 for map sensor and im not sure what the other was, on my car it now goes to a map sensor.

2 off the sides near the throttle body, and another near the top passangers side by the throttle body. Also there is the EGR hole. If all of thoes are connected you should be fine for vac

 

Yeah but you can check for possible valve seal problems and things as well with a vacuum test. My main concern is checking for an intake leak because on a scanner my Vacuum pressure is all over the place and I was hinted at by a guy here that I have a major vacuum leak in the intake. I think he is right. I haven't been able to turn anything up with carb cleaner sprayed along the intake.