Cleaning bottom EGR passage on Honda V6 - P0401

[Vikas]

1999 Odyssey van; 231K miles. About 4 years/50K miles ago, I cleaned the EGR passageway inside the intake plenum. This is a chronic and very well known issue on this engine.

So when the code came back recently, I cleaned the plenum again. Every youtube video says the passage from EGR valve to the intake is big and never clogs.

Unfortunately, few of us have been plagued with a clog in that area. To properly clean it, you have to remove the lower water pipe contraption from the engine which is quite a job. That passageway has too many sharp turns inside and does not seem to be a way to unclog via usual snaking method. I can dump cans of Berryman B12 and hope for a miracle. Stiff cable or coat hanger will not be flexible enough to go through too many 90 degree turns.

The EGR valve itself is 17 years old and has 231K miles on it! It might be the one clogged inside. I hope that is the case but will not know until I swap it with a new one.

Trav probably has lot of experience on this particular engine and EGR clogs and would love to hear from him.

 

[86cutlass307]

You can try a 50/50 mix of acetone and ATF (any residual you have) and pour into the tube; takes multiple attempts...you want to keep the carbon saturated as best you can then clean as best you can. You can try some large pipe cleaners twisted together or a small diameter, long stem engine cleaning brush. It takes a lot of sweat equity on this job, but it is worth it. The only way to fix long term is to R & R the tube. Good luck

 

[Vikas]

I am thinking I could strip RG6 antennae cable and try to snake it through but one really needs just the right kind of stiffness and bendiness to break through the carbon and still go through the entire passage.

I am looking (smoking) pipe cleaners but that does not seem like it will have enough stiffness.

I am looking at long tube brushes but they don't look like they are flexible enough.

I looked at medical grade CPAP tube cleaning brush but can not figure out where it stands in terms of flexibility vs stiffness. It also seem as if little too thick.

 

[Trav]

Get some C4 carbon remover (look online for it and a small diameter long flexible stainless steel brush from Grainger. Let the C4 sit overnight before go at it with the brush.
I would change the EGR valve.

Edit: Look at this company for SS spiral brushes.

http://www.spiralbrushes.com/brush-products/twisted-in-wire-brushes/

 

[Vikas]

Quote:
Get some C4 carbon remover
I hope Homeland Security does not come looking after me when I google C4

 

[The_Eric]

Originally Posted By: Vikas
Quote:
Get some C4 carbon remover
I hope Homeland Security does not come looking after me when I google C4


Between the NSA and Homeland, your goose is already cooked since you already typed in key words... Nice knowing you!

 

[Vikas]

Spent another day and managed to make a dent after lots and lots of efforts; close but no cigar. The passageway is now opened up a little bit but still not enough for the engine to make it stumble when commanded.

So far we have spent over couple of days taking off air intake box, EGR valve, intake plenum and did this twice so far + taking of just EGR valve few more times.

I don't mind doing experiments via EGR valve port but the next time I have take off the intake plenum, I am going to bite the bullet and do the major surgery to expose the passage as at this stage I just can not come up with a micro "roto-rooter" contraption.

Since I no longer need to worry about emission and this is not affecting immediate engine performance, the need to fix this is not urgent. However, that check engine light bothers me a lot. Besides this feels as if I am giving up on whatever tiny piece of man card that I have

 

[Smoky14]

I have had some success using a speedometer cable as a roto-rooter. I'm not familiar with your specific engine however so YMMV

Smoky

 

[nthach]

Find yourself some GM Top Engine Cleaner(or it's marine equivalent Valvtect Power Head Decarbonizer) and use that with some kind of object to clean up the passage.

I'm not sure about Honda's J-series V6s, but the H/F series engines with EGR have 4-5 small plugs in the intake manifold that seal the EGR passage - those are drilled out and then you can clean the passage.

 

[supton]

Originally Posted By: Vikas
Since I no longer need to worry about emission


I don't follow--how did you get a reprieve? I know I've heard that in Maine one can just clear the code and pass, as they don't check readiness flags, light just needs to be off; but otherwise I thought all other New England states required OBDII vehicles to pass emissions.

 

[Trav]

MA has a 15 yr limit and his is a 99.

 

[Vikas]

Ordered this:-

Might have to remove the end of the outer to snake it through.

Next time I am in mood, I am thinking of removing the EGR valve, starting the car and spraying the cleaner using the limited vacuum that I have and also trying to snake the cable while the car is running.

Could be stupidest idea too! But I just don't want to take off the plenum yet again without 100% sure plan.

 

[supton]

Originally Posted By: Trav
MA has a 15 yr limit and his is a 99.


Ah, did not know what. Wish I had that option! I have to go 1995 or older, here in NH. '99 and older don't need a title, but no other breaks.

 

[Rhymingmechanic]

On a Saturn with a blocked EGR passage, I was able to dissolve the carbon with Lube control LC20. I first tried throttle body or carburetor cleaner, buy that didn't work.

The tool I used was a piece of coat hanger, but it sounds like the passage was easier to navigate than yours.

 

[Gokhan]

At one point my engine was out-of-tune or malfunctioning, which completely clogged my EGR valve with rock-hard carbon deposits.

I was able to entirely carve out and clean the hard carbon deposits using a combination of CRC Brakleen brake cleaner green bottle and a large flat-bladed screwdriver.

 

[Ducked]

Originally Posted By: The_Eric
Originally Posted By: Vikas
Quote:
Get some C4 carbon remover
I hope Homeland Security does not come looking after me when I google C4


Between the NSA and Homeland, your goose is already cooked since you already typed in key words... Nice knowing you!


Continuing the weaponizing theme, IF you can get something all the way through, would a rifle pull-through technique be effective?

If you're pulling both ways, you loose the requirement for stiffness, and just need tensile strength. Knots and/or small springs, for example, at intervals along the pull-through, might do the actual scraping.

If I was doing that here I'd try heavy commercial monofilament fishing line, because there's a lot of it lying about.

Dunno how it'd stack up against the solvents mentioned above, but I tried DOT3 brake fluid as a carb cleaner recently and it seemed quite effective.

 

[Trav]

Did you order the C4, no joke that stuffs works great on carbon like this.

http://ads.midwayusa.com/product/984488/...CFclkhgodURoKgQ

Here is a brush that will work.

http://www.backcountrygear.com/camelbak-cleaning-brush-kit.html?gclid=CPrDgb754MwCFYEehgodoIkPbw

 

[Vikas]

thanks Trav, that is what I will do then.

 

[Vikas]

I took the inspiration from BG EGR Kit and made my own adapter and then used 3M Intake System Cleaner and fed the can through EGR passage. All I had to remove was the EGR valve and put my blocking adapter there and did NOT have to remove the intake plenum.

And it worked!!!