Nasty EGR passage completely clogged in civic HX

[turbovr41991]

Poor gas mileage and rough idle in HX civic. Had a coupe CEL lights so I investigated the EGR. COMPLETELY CLOGGED. Every cylinder clogged!!!



A wire brush, a shop vac, some carb cleaner, brake parts cleaner, and 30 mintues later it was running perfectly! Amazing what a difference it made. most people claim to go from 34 to 38 mpg with this cleaning on cars with 150-200k miles. Wonder what results I will get?

[brucepick]

Can you give some pointers on doing this?

I really should clean mine but I'm kinda scared to mess with the injectors - I never had one out before. The procedures I read say you need to remove the fuel rail and injectors to get access to the EGR passages, right?

If I do it, should I replace the injector o-rings? Do I need to lube o-rings before installing, and with what? And exactly how do you get the fuel rail and injectors off? Removing screws is no problem, but what do you pull on to get things apart and do you have to pull straight up to avoid damage?

[turbovr41991]

Originally Posted by brucepick

If I do it, should I replace the injector o-rings? Do I need to lube o-rings before installing, and with what? And exactly how do you get the fuel rail and injectors off? Removing screws is no problem, but what do you pull on to get things apart and do you have to pull straight up to avoid damage?

Only two 10 mm nuts hold on the fuel rail. I also took off one side of the vacuum lines in the area to free up the fuel rail. The throttle cable mount was also somewhat into he way so I unhooked that and pushed it aside a few inches. The injectors will pop out quite easily. Try your best to leave them in the fuel rail and only pull them out of the intake manifold. No fuel i wsted this way! Also, you can move the fuel rail with injectors somewhat out of the way (will not move too far if you leave them plugged in as I did. (should be able to see them suspended in my picture up there.)

Mine was clogged both in the recirculation plate and on the intake manifold. I used an pick, small screwdriver and a wire brush to clean everything out. I also had a shop vac running to try to suck up as much of the carbon from the intake manifold (mainly to protect the open fuel injector holes.)


I did not replace the injector O rings. I just wiped them down (carefully to avoid soiling the injector tip.)

I found this really good write up. Initially I was just going to replace the EGR and then after I found out about these small passages blocking I hat to try this first. Amazing fix!

Lots of write up instructions on the topic (some are for accords, other model civics, etc, but still similar.) The best one I found was Fixing EGR blockage leading to DTCs P0401 and P1491

A couple pictures from the link:



This "dirty" one looks perfect compaired to what mine was like. Mine had carbo completely blocking the passages to the 4 cylinders.

[02ws6]

Ive seen some old guys use oven cleaner... Works awesome!

[some_other_dave]

Careful putting oven cleaner on aluminum parts! If you leave it on for very long, it will eat the aluminum.

It takes anodized coating off the aluminum pretty quickly, which is what some people use it for.

-soD

[user removed]

I would replace the injector o-rings. No need to have a vacuum leak and have to go back and do it again. Make sure the seating area for the o-rings is clean as well.

regards
Mech

[1carnut]

Thanks for the very nice write up. Even I could follow it! Mine is a 97 with 189k and was also very dirty and blocked in several places.

[SpeedyCorky]

just did my 2000 HX with 120k. mine looked like the one in the picture - dirty, but not that bad at all. no blockages. cleaned it up super nice; reinstalled w/ new gasket. re-used my fuel injector o-rings, as they looked perfectly fine

[turbovr41991]

awesome! hope you see some improvements. I just took my EGR off today to inpect it. It looked ok but was tossing the bad egr valve code P1491. Lean burn has also been acting up since this code tripped so I was already considering replacing the valve. Then I found out about a really good sale at advanced auto parts for the OEM egr. 20% off, a $50 coupon for a future purchase and free shipping. So the normally overpriced EGR was brought down to an exceptional price with freee shipping. Will report back after I swap it!

[SpeedyCorky]

any update on that EGR replacement?

my EGR system seems to be working perfectly. the cleaning i mentioned in the above post didnt yield any gains in MPG. it wasnt very dirty to begin with, and i got in there and cleaned it to like-new. but its nice to know i got it done and i dont have to think about it for another 100,000 miles or so haha