how do i check or find where the vacuum leak is?



...also out of topic.
are the lug patterns of a FC(5lug)and rx8 the same?
..both 114 arent they?

 

First thing you could do is check all of your vaccum hoses to see if they are all hooked up and in the right locations. Also a good thing to do is to check if any of your hoses have cracks. Sorry for not to much help. Thats what I would do.

Just check them all. It will probably be annoying and take a few minutes but shouldnt be hard!

 

Appearantly you can use carb cleaner. Spray it in areas around the intake and when the idle surges upward You'll start getting an idea where the leak is. Most likely a vacuum hose cracked

 

I prefer spraying starting fluid instead. Not as explosive as carb cleaner (you need an actual flame-instead of just a hot surface).

The RPMs will increase if you spray starting fluid around a vac leak.

 

If you have an air compressor you can pressurize the system while the car is off and then listen for leaks.

 

i use brake cleaner to check, you can also use a propane torch that is on but not lit, the propane method only works if you can get it right up to the source of the leak though whereas the brake cleaner you can get under the manifold to find leaks.

always keep a fire extinguisher handy though just in case though i have never needed one and i have done it this way for years.

if you spray near a leak and the engine either drops RPMs, raises them, or smooths out temporarily then you have found the area where the leak is at.

 

Take a vacume guage, hook it up to a hose (such as the brake booster, because you dont need that one because you are parked when checking) and read what the vacume is at, it should be around 18ish, if its anything less than 15 then you deffinitely have a leak