Re: EGR system plugged
> 1980 Ford Tbird 255CID. (similar to 302)
> 1. Is this a vacuum actuated valve or backpressure type. It does not respond
> to full vacuum.
> 2. I assume the passage into the intake is blocked because the idle does not
> change when I open the valve and I cannot blow compressed air thru it.
> Plenty of exhaust air is getting to the valve. Problem is that I cannot find
> any opening into the intake manifold. There is a passageway towards the carb
> about 1/2" wide and 1 1/2" long but using various bent wires, coat hangers
> etc I cannot find any way into the manifold.
Your EGR valve is mounted to a spacer plate under the carb, correct?
All of the passages are in this plate. Remove the carb and plate, the passages can
be seen from the bottom. You will likely find the plate clogged with carbon. It sounds
like you have the valve off right now, you should have a large vacuum leak with the
car running. These plates had a habit of eroding between the vacuum and exhaust ports.
If, after cleaning, the casting looks thin then replace the plate. They used to be
available at parts stores but I haven't bought one in quite some time.
(You may find the passages have been filled with epoxy or something of that nature,
it was a common thing for people who wanted to "get rid of that emissions crap" back
On reassembly, be sure to use the correct carb and spacer gaskets. There were a few
Regards, Tom Adkins