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Thanks, I know how it works. I'm just wondering if it's supposed to seal or have a gasket. It seems like it should to prevent an air leak.
The egr is required with this system.
the vacuum diaphragm is fixed, can't turn.
the rod attached should be fixed to the diaphragm.
Is that rod spinning?
I guess if it doesn't leak enough vacuum, it should work.
What is going on with your egr?
failed smog?
running bad?
sticking?
the vacuum diaphragm is fixed, can't turn.
the rod attached should be fixed to the diaphragm.
Is that rod spinning?
I guess if it doesn't leak enough vacuum, it should work.
What is going on with your egr?
failed smog?
running bad?
sticking?
I can turn it which I thought wasn’t right. The car has a random Skip. One of the solutions troubleshooting is a vacuum leak.
Is this on your 82? Removing the EGR increases upper cylinder head temps a lot. Removing it puts you on your first step to ba$tardizing your EFI... LOL ...But it's your car.
Like stated above, feel under the EGR, have someone start engine, you should feel it pull in, and hold in (if it's cold). It may release after a while. Putting strict vacuum to it from, say, a vacuum hand pump, bear in mind there is usually a calibrated vacuum bleed-off designed into it. Bad ones the are usually obviously bad, no vacuum or movement. But the valve needs to seal at the pintle too.
There's an excellent GM training manual which goes through in pretty good detail what/how and why about each emission component. It's rather eye-opening. I can't remember which manual it is right now, I'm not near my literature. Maybe someone else knows. You can find these manuals on ebay for like $10 usually.
Oh, to answer your question, if you can rotate the vacuum canister, it doesn't necessarily mean it's bad, just that it's loose on it's cast iron base. But the way to test it is to feel for the diaphragm pulling 'up' and holding for a bit. Make sure the hose is good and routed properly (check your emission sticker).
If you have never had it off and cleaned it, that would be a good maintenance item to do. The passage on the bottom side can get heavily carboned up, as well as the intake passage. Doesn't mean yours it, but they 'can' get plugged up eventually. This is for many vehicles, not just C3's. Every long while they should be inspected & cleaned out with a screwdriver (carefully) and a shop vac if necessary, and put back in place. Older GM's are kind of a bugger to get a wrench onto too remove (maybe a crows-foot wrench??). May need to seal with a light film of RTV upon reassembly...or new gaskets are usually readily available.
Edit: if you DID need to replace it, make sure you get the 'right one' for your car. There should be a part number on your existing one (assuming it's correct ....which I wouldn't necessarily do). There are a few different types..(how they operate).
Thank you very informative. Yeah I’m afraid it’s leaking at that spindle but I did find my vacuum guage so I can try that. Maybe put some soap bubbles around it. One step at a time to figure out this Skip. Thanks
Someone gave me some real good information about what to check. My computer is having issues and deleted it. If you can reply again to frankb25@gmail.com
It would be greatly appreciated.
Last edited by frankenbro; Aug 22, 2023 at 05:12 PM.
