Blue96z28

Just a quick question, just pulled my EGR valve off real quick after my idle has reached an all time horrible roughness. It seems to operate reasonably free back and forth, although it has alot of carbon and whatnot, but when pushed down manually it does come all the way back up by itself. But my question is, it seems to rattle LOL, only way to describe it is maybe a bunch of small flakes inside it maybe? which when shaken, make an almost morraca(sp?)*jazz band instrument sound, bad description but thats all I can do. Is that normal? If anyone knows whats normal about the noise or valve movement, please gimmie a quick response so I can put it back together or go buy a new one.....

thanks in advance

OBE1 95Z28

Shoebox has a good write-up:

http://shbox.com/1/4th_gen_EGR.html

Blue96z28

Thanks for the link, but I actually read through that just before I removed it, thats where I got the idea it was likely causing my rough idle. But it doesn't talk about the rattling sound, which may or may not come up in a normal discussion about the EGR valve....lol. I don't have a vaccum pump or gauge to check it with, but if it is bad I think the extreme rattling should be a dead give away.....anyone know on the rattling?

CamaroUK

I can't help you with the rattle problem, however I believe you can test the operation of the EGR valve by pressing the diaphragm in while the engine is running, it should make the engine run bad whilst pressed in and then return to normal as it comes out.

TripKidd

hey, mine sounds just like that aswell.. sounds like little beads inside or something... not sure if its normal or not though.

shoebox

I wouldn't think there should be any rattle. I don't remember any rattling from mine (though I did not try it out as a band instrument ).

Blue96z28

Yea I tried that before I first took it off, and it did act as it should, almost killing the engine when I manually opened the vavle, but thats not really a test is it? Would seem that would only tell you if the valve is locked up or if its very very stick....right? Doesn't seem that test would tell you anything about the vaccum/diaphram operation since the large spring is closing it back after you release it anyways??

lol, ya. Its a decent rattle, I'm sure someone like you would have noticed it if it were normal and yours had done it, so I'll just assume something is wrong and replace it tomarrow, I'll post back and let you guys know if that fixes it, and if the new rattles also, I just won't bother installing it I guess.

Also, I don't really know what could be rattling, because if I manually depress the diaphram all the way down, and then put my finger over the vac port, it WILL hold it there 100% depressed, and then as I release my finger over the vac port it releases the diaphram slowly with a good feel and 100% closes up the valve also very tight, and it seems to rattle with the diaphram fully up or fully down.

Is there something else I am overlooking? I've cleaned the TB/IAC numerous times before, MAF is clean, gm opti is fresh, gm coil fresh, plugs fresh, wires 100%, can't find any vac leaks and all the hoses are in good shape, or recently replaced by me. Stock manifolds/EGR setup....dunno.

shoebox

If it operates properly, the rattle may be of no consequence.

JohnD

I had an ERG that didn't close completely and caused a rough idle or at least it was partially the cause. There was a missing platinum puck off of #6 spark plug on the ground side that was the other half. My EGR would open and close ok but it wouldn't seal when it was shut. I'm going to bend a torx wrench with a torch and take the front part off the old valve to see if I can clean it. This spending $80 for a new ERG every 50k mi. is getting old.

Blue96z28

Do you remember if yours rattled(any of the times you changed it) by chance?

JohnD

No rattling EGR valves. I have no idea what would even cause that.

Blue96z28

Just thought I would post an update, slapped on a new GM EGR vavle, rough idle 100% solved, new vavle did not rattle at all......so I'm seriously stumped on that, it held vaccum etc, perfect, but was obviously bad....since the new one cured it....don't understand what parts in there could rattle like that, if the diaphram was intact.

shoebox

I guess you cannot argue with success.