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.
It might be both, a backpressure variable transducer type egr would use
vacuum and backpressure to actuate the valve under different
conditions. Have no idea if this applies to your case but the 1990
Escort GT uses this type egr.
If it is not responding is the pintle clogged with carbon deposits?
Try cleaning the pintle if not already, egr valves are expensive and
for a 1980 good luck finding one.
I'm not familiar with your combination (even though I had a 1981 Cougar with
the same motor for a brief period). Some of these had an EGR cooler mounted
to the carb base plate..... My DVD manuals don't go back even close to that
far but you may want to study your installation closely.
Our area has always been pick ups and cars are usually one of those
"reaching for knowledge" type projects. Do you have an identifiable
driveability concern ? The EGR cooler may present some unique
Sorry I can't be more helpful ( I just know someones gonna pick up on this)
but advice has to start from somewhere and "it's old - get rid of it"
doesn't necessarily fit everyones budget...
All of the passages are in this plate. Remove the carb and plate, the passages
be seen from the bottom. You will likely find the plate clogged with carbon. It
like you have the valve off right now, you should have a large vacuum leak with
car running. These plates had a habit of eroding between the vacuum and exhaust
If, after cleaning, the casting looks thin then replace the plate. They used to
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
it was a common thing for people who wanted to "get rid of that emissions crap"
On reassembly, be sure to use the correct carb and spacer gaskets. There were
Regards, Tom Adkins
AAAhhh, I forgot about that style intake. I missed in the original post where
the motor was a 255. The vacuum passages are there in the throttle bores. They
be open back to the EGR mount.
From the pictures it would appear as though the EGR passage leads right from
the place the EGR valve mounts to the openings on each plenum of the intake.
What I would do is get some strong carb cleaner (I live Valvoline SynPower,
it's strong stuff) and spray it down the EGR passage that goes to the
intake/under the carb. If you don't see any coming out the passages under
the carb it is clogged/plugged. If that is the case I'd fill it up with
cleaner until it came out the plate the EGR valve mounts to and let it sit.
Perhaps that will dissolve the buildup/clog.
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