How do you know when your air box is blown?
 

I have a 76 911S w/2.7 liter engine. How can I determine if the CIS airbox is blown? And what are the symptoms if it is blown? I know about 6 months ago it back fired really bad on a start up. Ever since then it runs like crap. I even cahnged out the points & rotor, cap. That helped for about a day then it went back to running like crap. Thanks in advance.

If its blown, the car will not run at all.
To check, take out the air filter. Inspect the box (esp the floor of the box) as closely as possible.
There is also the seam of the box, you should check that carefully, too. Its glued and screwed together.

You can spray starting fluid around the box to see any changes in idle speed

Warren suggested at one point getting under the hood at night and poking a flashlight in there, and seeing if you could see any light. That should reveal any cracks that are very small.

------------------
Mark Szabo
1986 911 Targa 3.2

By it's huge smile and the need for sleep?

I'm not even going to ask...heheh. http://www.pelicanparts.com/ultimate/biggrin.gif

------------------
Mark Szabo
1986 911 Targa 3.2

Don't use starting fluid!!!

DO NOT USE STARTING FLUID!!!!!


You can use carb cleaner, but starting fluid is ether and extreamly flamable. Try spraying some on the ground, write your name in the concrete, then light it. Looks kind of like the movie the Crow. Not a good thing bouncing around in the engine compartment.