After failing Atlanta metro emissions test, due to high nitrogen oxide, I tested my EGR system. No CEL should mean the valve is working but to check, I put my Mityvac on the valve and applied vacuum at idle...engine should stumble or die. Made no difference. This told me that the metering ports from the EGR chamber to the intake runners were clogged.

If you look at the intake manifold (3rd gen twin cam) You can see welded (?) over projections which I figured was where Honda drilled thru the EGR chambed to create the metering ports into the runners. I drilled these with a 27/64" (the size needed for 1/2" tap) taking care not to go too far. I was right, and I cleared out the metering ports with a small drill bit (hand held..don't want to resize the ports) I also drilled the other three welded over spots for cleaning purposes. I used oven cleaner which kicked the crap out of the carbon buildup but turned the aluminum dark gray (

A .44 caliber brass bore brush was handy for cleaning out the EGR chamber. After a thorough cleaning the 27/64" holes wre tapped with a 1/2" course thread tap. I used 1/2" x 1/2" allen key plugs with silicone sealer in the threads to plug the holes.

Original test was 2294 ppm (allowable is 1313 ppm) retest was 743 ppm.





As you can see, this was done in my driveway... The spots with the roman numerals are where the actual metering ports are located.


Modified by GlenWatkins at 6:16 AM 5/31/2006

 

nice dude, i gotta do this too.

 

I feel for you, I've had to do this, but I'm lucky, mine has the factory ports, so i just had to pull brass plugs out. like your use of the gun barrell brush, good idea.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by limpmode &raquo;</TD></TR><TR><TD CLASS="quote">I feel for you, I've had to do this, but I'm lucky, mine has the factory ports, so i just had to pull brass plugs out. like your use of the gun barrell brush, good idea. </TD></TR></TABLE>

Has anyone done this on a 4th gen and is it a similar process? Are the ports in the relatively same place as shown in the 3rd gen picture?

 

i did it to my 5th gen accord (f22) and it was pretty easy. be careful not to lose an injector o-ring like i did though

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by sYn &raquo;</TD></TR><TR><TD CLASS="quote">

Has anyone done this on a 4th gen and is it a similar process? Are the ports in the relatively same place as shown in the 3rd gen picture?</TD></TR></TABLE>


It depends on what motor you have in your 4th.some have plugs, other have to be drilled and tapped like this.

Also, they are not always in the same place, his has an uneven pattern due to the center runners being closer together, mine has an even pattern across the top with nothing on the side.

Mine for comparison:

There's another one in there you can't see with the fuel rail and such on.

Point is they are different, but same basic process, just some have to be drilled to create the ports.

 

Just keep in mind that you only want to drill into the top of the EGR chamber. That's like 1/3" or so of soft aluminum. You don't want to drill through the chamber and into the top of the intake runner. The metering port is pretty small and you wouldn't want to enlarge it. When you use the tap don't fully thread the hole. This way, your plug will not extend into the chamber.

 

^^^ Good point.

 

Another detailed writeup someone did

http://www.hondaprelude.to/for...t=egr