The accumulation of unburnt fuel, in the form of hard carbon deposits in the EGR system can drastically decrease the fuel efficiency of your Honda and Acura automobiles.

The EGR system refers to Exhaust Gas Recirculation and it was developed in the 1970s for the purpose of reducing car exhaust emissions.  The operation of the EGR system is simple. By recirculating a small amount of exhaust gas back through the engine,  during acceleration and cruising speeds; the combustion chambers stay at a slightly cooler temperature. This results in the fuel burn being more controlled by preventing the air / fuel mixture from igniting too early,  because of the heat that is produced by the engine.  This complete and controlled fuel burn does two things:

1. First, a fuel burn at the precise time provides the best “bang for the buck”. If the combustion chambers get too hot, the gasoline (especially lower octane gas) can ignite in the combustion chamber too early.  A fuel burn that occurs too early or too late makes an engine very inefficient.
2. Second, an improperly timed, inefficient fuel burn causes a tremendous amount of vehicle emissions that include:

• raw fuel vapor,in the form of hydrocarbons (HC)
• partially consumed fuel in the form of carbon monoxide (CO)
• nitrogen oxide (NO)….. Please do mistake nitrogen oxide for nitrous oxide. While you may be administered nitrous oxide (laughing gas) at your dentist office; nitrogen oxide is a very poisonous gas that is no laughing matter at all.

Back in November of 2008, I wrote a blog (with photos) on the proper way to clean the EGR system and this particular article referenced a 2004 Acura RL.  I invite our readers to go back and review it. http://accuratecars.com/blog/2008/11/25/insufficient-egr-flow-on-honda-and-acura-cars-accurate-automotive-says-save-money-and-do-it-right-the-first-time/

In this November article I referenced that to compete with price, some  Acura dealership service departments and other shops were cutting corners by not removing the intake manifold to properly clean the EGR system.

Just yesterday, our service manager received a phone call from a customer in Nashville that had taken his Acura RL  to an Acura dealership service department a few months ago to have this procedure performed and just a few months and a few thousand miles later, it was clogged again. The Acura RL owner told us that the franchised Acura dealership service department claimed that he was using lower octane fuel and this was causing an accelerated build-up of carbon in the EGR system.

The reason the EGR system is clogged again is likely because it was not properly and completely cleaned a few months ago. To properly and completely clean the EGR system on the 1996 through 2004 Acura RL, the intake manifold must be removed.  For the charge, that this Acura owner says was well over $300; the franchised Acura dealership service department probably did not remove the intake manifold.  Instead, they probably chose to just remove the rear metal EGR flow pipe at the back of the intake manifold and run a piece of wire or pipe cleaner through the rear plate and EGR port.  This would only clean out the area where the pipe cleaner could reach, which is only a small percentage of the area that accumulates the carbon build-up (see photos below).

This is probably why the EGR system clogged again in such a short amount of time.

At Accurate Automotive, we care about our Honda and Acura owners and their expenses. These expenses include the money that is spent and the time that our customers must leave their Honda and Acura vehicles with our service department.  In this case, when we remove the intake manifold and properly clean the EGR system in this Acura RL;

the EGR system should remain clear for at least  80,000 miles. The exhaust gas recirculation flow will then be within the design perameters to keep the combustion chambers cool and the engine operating efficiently.

This Acura owner will see a significant increase in miles per gallon (MPG) and he will be satisfied in knowing that the EGR system was properly cleaned and will not need to be cleaned again for several years.