Have an all-stock 305 TBI in a 92 Camaro. The EGR valve has a 90* fitting on top that the vacuum line connects to, which looks stock to me (and the valve looks relatively new).

However, the 90* fitting is PLASTIC and it has a little wobble to it if you try to move it around some by hand. Didn't look kosher to me so I put my vacuum hand pump on it. Leaks vacuum like crazy- can't hold vacuum for ANY length of time. Drops stright to zero as fast as I can pump it. The leak is definitely coming from around this "wobbly" 90* fitting.

My question: Is this a built-in vacuum leak that's supposed to be like that? I know the factory sometimes uses a small secondary leak to help calibrate the valve, but this seems excessive to me, just from experience.

Thoughts/comments/conjecture?

 

C'mon guys- somebody's gotta know. This is a pretty simple question. Could someone hook up a hand vacuum pump on their known-good TBI EGR valve and tell me if it's supposed to hold vacuum indefinitely or if it's got a calibrated vacuum leak that lets it bleed down real quick?

Thanks in advance.

 

I just replaced my EGR the factory one had a metal vaccum connection that did not move. The replacement had the plastic nipple that moved. Let me quote the caution in the instructions.
"CAUTION: Do not attempt to turn vaccum nipple at top center of valve. This will cause improper engine operation and necessitate valve replacement. After installation, it is normal for the plastic elbow to rotate on the vaccum nipple without causing a change to EGR calibration"
You can check your EGR by setting engine to fast idle and remove the vaccum to valve. you should see the diaphragm move and RPM should go up a little. Put it back on Rpm drop and diaphragm move again. I hope this helps good luck.
By the way it also says that Due to internal design a vaccum pump bench test is meaningless.

 

RS- thank you very much. I'm going to try that on-engine test you described. My valve looks new and definitely has that "swiveling" plastic vacuum fitting indicative of that type of relacement EGR valve. Just no way to know if anyone "spun" the fitting before they installed it, causing damage. The on-engine test should tell the tale. I'll post back in the next few days with the results if anyone is following this thread and might like to know.