A vehicle's exhaust gas recirculation (EGR) valve passages will have carbon buildup over time, which can lead to reduced efficiency, poor fuel economy and a "Service Engine" or "Check Engine" light. The buildup could also cause you to fail an emissions test, if the tests are required in your state. The EGR valve is located in a convenient location in the '93 Accord. This makes removing it, cleaning its passages and replacing it less difficult than on many other cars.
Shut off the Accord's engine. Inspect the engine bay to find the EGR valve. It is mounted near the right side of the valve cover (when facing the engine), next to the air hose assembly and intake manifold. The valve is about three inches tall, and the top looks like a saucer.
Pull away the vacuum hose from the top EGR port gently. Don't use tools for this, or you might damage the fragile hose. Just use your fingers.
Inspect the side of the EGR valve closely to find the two bolts that hold it in place. Remove them with your socket wrench. If the bolts are difficult to remove, spray them with a bolt loosening solvent, wait five minutes, then try again. Use a socket extension to remove the bolts if necessary.
Lift the valve away. You'll find a small gasket. Remove it as well. Discard the old gasket.
Spray the EGR valve passages well with a carbon cleaner safe for catalytic converters. Let the cleaner penetrate the carbon buildup, then insert the twisted edge of a rag into the passages. Turn the rag to wipe away the buildup from the inside of the passages. Repeat until the passages are clean. You can also use a handful of cotton swabs to clean the passages.
Let the EGR valve air dry until it is no longer wet. Apply the new EGR gasket to its mount, then attach the EGR valve. Tighten the two bolts well and plug in the vacuum hose.
