Hey everyone,
So my 99 TL with 160 thou on it has been coding P0401 for the last year or so. I have lightly tapped the EGR and sea-foamed the fuel when it happens and it goes away for a few thousand miles (yes I bought a code reader at 130 thousand miles when the check engine light started going on every week or so). Today I removed the EGR to see what is going on as a precursor to removing the manifold and doing the faq cleanse. I thought I would see a clogged port -like the images from a cholesterol reduction commercial. Other than some minor scaling and a ring of carbon around the EGR valve seat it was clear. I removed the carbon from around the EGR valve, scraped out the port and replaced the EGR.
First thing I noticed was how smooth it idled and on the test drive it had better throttle response. So my question is: Where is the obstruction created in the EGR system and is the carbon around the EGR's valve area enough to cause the code?

 

Hi RC :

I think I'm becoming an "expert" on the TL EGR port/valve. The usual location of the blockage is in the intake manifold plenum right inside this port and the solution is well documented in the DIY section. We both have a 99, so it only has one port. Mine was clogged with black soot and completely blocked.

You might want to read my posts regarding my fight with this problem. In fact today, I just redid the cleaning process with a coat hanger to try and correct the EGR error.

Take look at my last post which details a much faster way to remove the IM plenum.

smartypants

 

you are using the acura method of IM removal for recall/warranty work on egr-
they are looking to save time
While we are looking to clean IACV (bottem of TB) and other parts, do a little service to the system so it runs forever

most people find the manifold port(s) plugged, not just the valve end -thats why you remove manifold and clean egr till spotless

 

Does the egr just tap into the nearby cylinder's exhaust manifold- then back into the manifold plenum?
When you mentioned the manifold ports which one(s)? And when I had the service recall for the egr update, what exactly did they do? I was under the impression a bypass tube was installed to increase egr passage volume to reduce the build up.
Thanks for your insights.

 

Hi RC :

So as not to repeat information already available, go to the DIY section and read the Service Bulletin and the experiences of other folks in the related posts. It explains the whole EGR issue very well and the work that needs to be done to clear the port.

smartypants

 

the 99 has 1 egr port- it clogs easily
the recall cleaning of it installed an 8mm diameter tube in the existing port (slight enlargement with drill bit before install) thats not very big,,the smaller bolts on the car are 10mm head for comparison

the logic was a smooth bore surface would catch less crud than rough casting
By it didnt

00 and on have 6 egr ports - 1 per cylinder and still plug the egr every 75kmiles!
thats per our megamod with 350kmiles on his TL and several diy egr services

exhaust is draw from that manifold, routed thru the intake to each cylinder,,, and clogs each of them, and all the passageways
thats why you clean more than just the opening- must clean pathway

 

Thanks!
I checked the faq and will be doing the complete service this weekend.
You all rock...