Are EGR valves fast acting? Meaning when you test them (finger) method, do they close fast?

Thanks.

Pretty fast.  I had one that made a farting noise sometimes as the actuator vacuum pulses changed.  That's a fairly fast frequency.

17 hours ago, DC871F said:

when you test them (finger) method, do they close fast

I'm not really sure what you're asking here... If you are asking "if you manually open them by sticking a finger up into the valve to push the diaphragm up, does the valve close quickly when you remove your finger?"

If that's the case, then the answer is "It will close as quickly as the air can get back into the chamber at the top of the actuating diaphragm."

So, reaching a little and trying to guess what you're really asking... If there is nothing connected to the vacuum nipple and you push it open with a finger, I would expect it to close pretty fast. However, if you've got a piece of vacuum tubing connected to the EGR valve and that tubing leads to a closed off thermal vacuum valve or something, the EGR will close a lot slower.

Does any of that make sense? Did I say that right?

36 minutes ago, Captain Obvious said:

I'm not really sure what you're asking here... If you are asking "if you manually open them by sticking a finger up into the valve to push the diaphragm up, does the valve close quickly when you remove your finger?"

If that's the case, then the answer is "It will close as quickly as the air can get back into the chamber at the top of the actuating diaphragm."

So, reaching a little and trying to guess what you're really asking... If there is nothing connected to the vacuum nipple and you push it open with a finger, I would expect it to close pretty fast. However, if you've got a piece of vacuum tubing connected to the EGR valve and that tubing leads to a closed off thermal vacuum valve or something, the EGR will close a lot slower.

Does any of that make sense? Did I say that right?

ZED HEAD got the meaning. The first sentence I wrote was just asking if EGR valves open/close fast. Should have said (open/close). The finger method of testing ERG's is putting a finger on the underside where the diaphragm is to see if it is responding to engine RPM.

Thanks

14 hours ago, Zed Head said:

Pretty fast.  I had one that made a farting noise sometimes as the actuator vacuum pulses changed.  That's a fairly fast frequency.

Thank you. I was pretty sure that was supposed to be the case, mine moves in slow motion.

Could be sticking. Varnish and deposits can build up on the valve actuation shaft. Try soaking the bottom part of the EGR valve in Carb Cleaner overnight. Then spray with PB Blaster or Move-It. A stuck or sticking EGR Valve can cause erratic idle and low speed running. 

16 minutes ago, Chickenman said:

Could be sticking. Varnish and deposits can build up on the valve actuation shaft. Try soaking the bottom part of the EGR valve in Carb Cleaner overnight. Then spray with PB Blaster or Move-It. A stuck or sticking EGR Valve can cause erratic idle and low speed running. 

I replaced the EGR with a new one. Kept the old one, so I'll give it a go.