I have an 82 and I have fuel in the vac line going to my front dampener, so my question is, what exactly does the dampener do? and is it necessary to replace it before a smog test?

 

The damper smooths pulsations in fuel pressure that occur when the injectors fire. The amount of pulsation and the related pressure drop through the system vary with the duty cycle of the injectors, with minimal need at idle and more need as engine load goes up.

The issue for the smog test is that you have fuel passing through the diaphragm on the damper, being pulled into the engine intake through the vacuum hose. Unmetered fuel. The amount fuel passing is related to fuel pressure and intake pressure (vacuum). If the leak is very very small, there may be enough compensation available from the oxy sensor at low load to mask the problem. But I wouldn't want to bet on it. Plus if you don't pass the firs time, you'll be fixing the leaky damper and hoping that it was the only problem.

Here in the great and socialist republik of Kalifornia, missing by a lot on a smog check, or not getting it fixed within a couple retests can be grounds to tag the car as a "gross polluter". That lifetime designation opens up a whole new can of bureaucratic worms for the rest of your ownership period. Don't know if your car is exposed to that kind of criticism. But the reality is that you need to fix it anyway at some point, so it might as well be now before the test.

 

yeah your right i'll replace it thanks!

 

make sure to check any other dampers or FPRs that vacuum lines going to them if one has failed the others cant be far behind, though you may only have one,

also inspect any 3 or 4 way tubing connectors once gas gets into the lines the rubber will go soft

 

I guess the function of a fuel damper is the same for modern tin boxes as well, regardless of the system's pressure? Would it be possible to swap the expensive vulnerable Porsche items with modern items from any scrap yard (when originality and connection aren't problems)?

 

I have had my front one blocked off for a year. Ran a little rich
Now I am installing larger fuel rails and this system does not get the one in the front.