Thread: Warming Up
View Single Post
lucittm lucittm is offline
Manassas, VA
 
lucittm's Avatar
 
Join Date: Apr 2007
Posts: 1,211
Garage
The smoke test is a valuable toubleshooting tool for our cars. There are probably 100 potential leaks in the intake system. Not so many more than other cars, but a leak there has a dramatic effect on Porsches.

The tech will block the throttle plate wide open and seal off the intake at the air filter except for a small fitting. Using the fitting, he will use a "smoke machine" to pressurize the intake system with 1-2 psi of the same kind of smoke used in hollywood movies; it is made from mineral oil. The leaks where the smoke comes out will be obvious and usually require tightening a fitting or replacing a vacuum hose. Sometimes a hose has popped off, it's just not very plain to our eyes.

The sputtering is classic misfiring and could be one or two bad plugs (cheap) or a bad injector (expensive). I would try the plugs first. You could have fouled one upon start-up after sitting that long. It would be good to know what kind of plugs you have anyway. Since you don't drive it too much, maybe a plug in a warmer heat range would help.

There is a well-documented injector test on this forum, just seach "injector flow test". Did you add new gas after the car was sitting? Bad gas (water) is always a source of misfiring or not running at all.

Also, include some pictures, especially of the engine. It will help folks to visualize your issues.

Good Luck,
Mark
__________________
1991 964 Polar Silver Metallic Turbo Coupe
Old 02-03-2009, 02:36 AM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #4 (permalink)