I'm helping out a friend who has a '80 Impala, 305, 130k miles

We suspect the egr valve is bad, applying vaccuum doesn't make the valve move. We removed it from the car, and manually moved the valve, it moves freely. It wasn't plugged up with carbon, lokked relatively clean. It doesn't move using vaccuum, it just seems to leak air.

I'm I missing something here, does this EGR valve function differently than the old ones I'm used to? Does it need some exhaust pressure against the valve, along with vacuum at the diaphram?

We bought a new one at the local parts store, and it does the same thing (nothing).

We took the old one to the local dealer, he tested it with a vacuum pump, said it was bad, and dealer replacement is no longer available.

The guy at the local parts store seems to think his part is good, and doesn't want to give us a refund.

 

They work just with vacuum. Diaphram on old one is probably torn. As far as new one, it's not unknown for parts to be bad brand new. Only thing you can do is apply vacuum and see if they work.

Just toss it and get a block off plate, unless you need to pass emissions.

 

SOME of the late model EGR valves (for instance the one used on my 91 305 TBI Camaro) say specifically in the instructions that a bench test is meaningless. I tried. It's definitely meaningless- there must be a secondary bleed somewhere that outruns my hand vacuum pump.

I do not think that would apply to ANYTHING built before the mid 80s, but you need to check the instructions that come with the valve to be sure.

 

What does the car do when a EGR valve goes out will it cause a surge or RPM drop when you stop? Sorry not trying to Jack your thread I just wanted to know what happens.