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If the temp guage on a Festiva with a carburetted engine starts to creep up, or if an emissions test shows elevated nitrogen oxides, the most likely cause is a dirty Exhaust Gas Recirculation (EGR) valve. It's free and easy to clean compared to replacing the thermostat which is what people tend to do with no improvement. I've owned my Festiva 22 years and have cleaned the EGR valve twice. The first time I wrote up a description and posted it on a now defundt website. I've copied and pasted it below. I just cleaned it again yesterday and this time took three photos which can be seen with a description at http://www.photobucket.com/Festiva-EGR . This time I used a quicker procedure.
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I cleaned my first EGR valve today and am writing this down for
car owners who might want try it. Before trying I did some
research at the public library and studied several diagrams of EGR
valves.
My EGR valve has an aluminum lower body with a steel upper body
crimped onto it. It can't be taken apart and cleaned. The upper
body is the vacuum chamber which lifts the stem that fits into a
hole in the lower body where the exhaust gas must pass to be
recirculated into the engine. There is a rubberized diaphragm
which can be pushed with a finger to make the stem go up and down.
This EGR valve is held to the engine with three bolts which were
easy to remove. Between the aluminum EGR valve and the aluminum
engine there is a thin stainless steel gasket. My EGR valve has
two rubber hoses connected to it which must be removed. I find
hoses come off easier after a shot of penetrating oil or WD-40. A
small screw driver was used to pry the hoses loose.
I took the EGR valve to my workbench and soaked it in paint
thinner ("universal solvent") for a few hours. The solvent made
the carbon deposits soft. I carved a small smooth wooden plug to
wedge between the upper and lower bodies of the EGR valve to hold
the stem out of the hole so the solvent would soak the opening. I
gently pushed up on the rubber gasket with two fingertips and
inserted the wooden wedge. The valve was immersed so the solvent
covered the stem opening but did not touch the rubber diaphragm.
The stainless steel gasket was also soaked in the solvent.
When the carbon deposits were soggy I gently scraped them off with
a small screwdriver. I used a bicycle spoke to get at hard to
reach places. The thread on the end of the spoke scraped the
carbon off well. To get inside the hole and around the back of the
stem a bicycle brake cable was used, bent to suit. The end of the
cable has several wire ends which act like a wire brush. I had to
be careful to remove any wire ends which broke off so they would
not be left in the valve. The spoke was used to poke a thin strip
of cloth around the stem. The ends of the cloth strip were then
pulled back and forth to clean the carbon from around the stem.
The stainless steel gasket was cleaned with a rag soaked in
solvent. Stubborn spots were scraped with a thumb nail to avoid
scratching. The surfaces of the EGR valve and the engine which the
gasket separates were also cleaned with rag and fingernail. I read
somewhere it's especially important not to scratch these surfaces.
After cleaning, the EGR valve and gasket were rinsed in solvent,
dried as much as possible with a cloth and left to air dry. Its
important that nothing like bits cloth fibre be left in the valve
where they would be sucked into the engine. I did not try to clean
out the holes in the engine because I did not want to knock bits
of carbon back into the engine.
When the EGR valve had dried it looked clean, especially where the
stem seated in the hole, and worked smoothly, I put it back on the
car, tightening the bolts snug with moderate pressure on the
rachet handle.
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I cleaned my first EGR valve today and am writing this down for
car owners who might want try it. Before trying I did some
research at the public library and studied several diagrams of EGR
valves.
My EGR valve has an aluminum lower body with a steel upper body
crimped onto it. It can't be taken apart and cleaned. The upper
body is the vacuum chamber which lifts the stem that fits into a
hole in the lower body where the exhaust gas must pass to be
recirculated into the engine. There is a rubberized diaphragm
which can be pushed with a finger to make the stem go up and down.
This EGR valve is held to the engine with three bolts which were
easy to remove. Between the aluminum EGR valve and the aluminum
engine there is a thin stainless steel gasket. My EGR valve has
two rubber hoses connected to it which must be removed. I find
hoses come off easier after a shot of penetrating oil or WD-40. A
small screw driver was used to pry the hoses loose.
I took the EGR valve to my workbench and soaked it in paint
thinner ("universal solvent") for a few hours. The solvent made
the carbon deposits soft. I carved a small smooth wooden plug to
wedge between the upper and lower bodies of the EGR valve to hold
the stem out of the hole so the solvent would soak the opening. I
gently pushed up on the rubber gasket with two fingertips and
inserted the wooden wedge. The valve was immersed so the solvent
covered the stem opening but did not touch the rubber diaphragm.
The stainless steel gasket was also soaked in the solvent.
When the carbon deposits were soggy I gently scraped them off with
a small screwdriver. I used a bicycle spoke to get at hard to
reach places. The thread on the end of the spoke scraped the
carbon off well. To get inside the hole and around the back of the
stem a bicycle brake cable was used, bent to suit. The end of the
cable has several wire ends which act like a wire brush. I had to
be careful to remove any wire ends which broke off so they would
not be left in the valve. The spoke was used to poke a thin strip
of cloth around the stem. The ends of the cloth strip were then
pulled back and forth to clean the carbon from around the stem.
The stainless steel gasket was cleaned with a rag soaked in
solvent. Stubborn spots were scraped with a thumb nail to avoid
scratching. The surfaces of the EGR valve and the engine which the
gasket separates were also cleaned with rag and fingernail. I read
somewhere it's especially important not to scratch these surfaces.
After cleaning, the EGR valve and gasket were rinsed in solvent,
dried as much as possible with a cloth and left to air dry. Its
important that nothing like bits cloth fibre be left in the valve
where they would be sucked into the engine. I did not try to clean
out the holes in the engine because I did not want to knock bits
of carbon back into the engine.
When the EGR valve had dried it looked clean, especially where the
stem seated in the hole, and worked smoothly, I put it back on the
car, tightening the bolts snug with moderate pressure on the
rachet handle.
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