ezone

Yes, the housing that holds the EGR valve has passages from the intake and the exhaust both leading to the EGR valve, and a coolant passage. All through the cylinder head casting.

fsckewe

So, I got it off.

Hey man, no need to apologize, I certainly understand. I was just brainstorming out loud. It's easy for me to forget you work on more than just D17A2's!!

I just needed to think about it and get creative.

That is the constant theme in my mind "If I can just break it loose, I can get it off with my fingers."

The passages are pretty cake in carbon and I can't even see the holes into the head. Off to cleaning. Thanks for all you help so far ezone. I'll give an update once I get it cleaned and back together and driving.


So, for anyone who finds this or anyone watching who cares:
- Leave the fuel rail on.
- Take the two long nuts off at the top and leave the center bolt on at the top.
- Take the two outside bolts on the bottom off.
- Take the center nut off on the bottom and leave the two outside nuts on the bottom for now.
- To get the center nut off the bottom, I had to take the rectangle piece of metal that looks like a fuel rail support off. (#5 in the first image. You will need to take of #15 first.) Then easy access to the nut from the top(there is a cutout/slot to access it.) No need to **** with getting under the car or taking the oil filter off. This can all be done from the top.

ezone

Dude, I don't even bother to try to remember what all the different engine numbers mean. That doesn't help me solve problems.
Info systems don't care either. I need year, make, model, engine size, body style, trim level for most info lookups.

People ask what horsepower their engine has, and I have no clue. I don't need to know anything like that to fix 'em.


Did you find at least one EGR passage still open into a cylinder, or was it just impossible to tell?

Keep us posted on the outcome.

fsckewe

Makes complete sense.

So, the passage for the #1 cylinder was completely blocked at the head. The #2 was just a pin hole, while #3 and #4 were lightly bigger than pin hole. Also, the #4 intake tube/port has a bunch of carbon build up. The other 3 are fairly clean. But lots of black gunk on #4. I'm guessing the head and cylinder for #4 have some build up. I haven't looked to much inside the head, but I'm certain it's there.

So the million dollar question is: what caused this and what can I do to prevent this occurring again? Wrong oil? Repeated use of bad fuel? Short trips?

ezone

Normal.
It's just carbon (soot) from the exhaust.
Some people get it, some don't. (Driving habits.)
They all might/could do it eventually. How long? Can't predict that.
You can't stop it.
Yours took 100k to get this bad, so (in theory) it should take another 100k to do it again. You still gonna have that car at 200k? 300k? If you aren't the original driver that racked up the first 100k, your habits will probably be different.
How long had your EGR valve been stuck open? Irrelevant now.
EGR isn't supposed to be active until the engine is somewhat warm, and is only active at part throttle.
The more you can get clean, the longer it will last.

Driving habits may aggravate buildup, and fuel quality may too.
Seems to make the carbon build up quicker.

Read about fuel quality again:
http://www.toptiergas.com/

Yes, pull off the EGR valve and make sure the passage is clear between it and the intake manifold through the head.
Clogs always start at a/the pressure/temperature drop point(s).

On certain EGR passage configurations, I have been known to BURN the carbon out of aluminum (or steel) with a torch (oxy/acetylene). Start the carbon glowing, shut off the gas, leave the O2 running until it burns out all the carbon. Other people think I am NUTS, but I'm not the one fighting with cleaning snaky passages (I'm all about less work and faster!). I wouldn't try it on one of these though. Too many outlet ports, and too close to plastic. If your port through the head was full of carbon, I COULD use this method there after the plastic manifold is out of the way.

Starting with 06 on the Civics, the mfr moved the pickup for the EGR to after the cat in an attempt to provide the EGR with cleaner exhaust source. Time will tell if that was a good move, but so far it seems to work, haven't had nearly the amount of issues these days.



Cheapo discount fuel doesn't always get all the good cleaning additives. I know around here we have a few people that insist on getting fuel from the convenience/beer/lottery ticket stores because 1¢ cheaper gas is the best thing since sliced bread.

I really haven't had to do this with these Civics but like once (I do clean them when the head is off for a head gasket job though).
Heck, I have one customer with a quarter million highway miles on an 04 with no EGR issue. Yet.
I know they are probably out there, but the dealer I work at is relatively low volume compared to like a metro area.

The Odysseys that had the issues with EGR clogging and got a warranty extension.....most people only need the cleaning like every 80-100k or more. We have a couple people that needed it every 40k, and all I can think of is driving habits and fuel quality.

I have a different story about a whole family (3 different brands of cars, Isuzu, Dodge, GM) filling with fuel at a local lottery and cigarette store on the same morning, and all of the cars had stuck injectors within an hour. I named the brand of gas on a hunch, jaws dropped when I guessed that. LOL. (The GM car -- I could expect it to stick an injector, but not the other two.)

ezone

You tried to clean the EGR valve and its passage with what? Liquid? That could turn the carbon to BLACK GOO.

Whichever ports were still open should be the cylinders that were misfiring, or at least whichever port would have still had the most flow. Exhaust gas is inert and too much of it will kill a cylinder.

fsckewe

I had sprayed some carb cleaner in the passage under the egr to help break things up. I had left the egr valve off over night to let it dry....But, it looks like it did goo up. The #1 and #2 intake ports on the head were fairly easy to clean (they were the most clogged at the injector base.) #3 had a little more buildup, but #4 has a **** ton. And it's kind of soft and harder than **** to get off. I've had a pretty good go at it and it's still covered in carbon. Waiting on gaskets in the mail, so I'll have another go tomorrow.

The one that wasn't throwing the code(#2) for misfire was definitely clogged big time.

Although I really have nothing to compare this too, it seems like a ton of build-up on #4. I guess I'll just have to check it again in 80-90k as a routine maintenance. I'd like to keep this car for 250k+ like I had my other two Honda's. I'll have to see how the other maintenance items go.

ezone

You don't have to get it all shiny and new, just get all the buildup scraped out.

fsckewe

OK, long delay but I'm back. Had parts hell. Parts got lost in the mail. Re-order took forever and I've had some other projects going on.

At any rate, got the egr passages on the injector base super clean. Spent a fair amount of time on the intake ports on the head. The #4 was pretty dirty and the carbon had turned to black goo (from the carb cleaner I suspect) but I got most of it out. Cleaning between the egr valve and the passage ways was a little tricky and I'm not confident I got it very clean.

Torqued everything to spec. Replaced some hose clamps, replaced o-rings and gaskets galore. And from my current level of ignorance, it seems to be operating as expected. I actually got it smoged Saturday, and it passed.

The only thing I did not replace was the valve cover gasket. I need to do the timing belt (or have someone do it) so I will replace it then.

No misfiring, no codes. All seems well except one monitor will not go into the ready state. The EVAP monitor stays in the Not Ready state. I've driven a few drive cycles and attempted to hold steady throttle at interstate speeds for 90 seconds, etc, etc, etc. I've only hooked up my code reader. Will hook up the computer and dig in deeper.

One last thing, I talked to a local honda mechanic at an independent shop who said he likes to leave the intake manifold gasket on. That they can be hard to get sealed back up. I had to take it off as holes were clogged on it and it was covering opening that needed cleaned.

ezone, ever have any problems with this, or any suggestions? I torqued everything to spec. Can I check for good seal like I would for vacuum leak by spraying some carb cleaner around the gasket and listen for idle changes?

Thanks for all your help,

ezone

I was wondering how it was going there, good to hear it!

Probably not a big deal, the majority of buildup occurs in the manifold plate.

LOL

If the gasket was still pliable, it should be just fine. As long as it doesn't leak when you are done. We lift them for timing belt maints and don't replace the gasket all the time. A little tiny dab of RTV in the corners of the cam cap humps if you like.

Leave the intake gasket on what? Reuse it? I'm not following here.
Silicone rubber seals and steel gaskets can usually be reused without a problem. A fiber or paper gasket doesn't always work so well that way, once it tears it is done.

I'm not following what you are asking here. It runs great, right? Misfire solved, right? No more codes, right? PASSED THE EMISSIONS TEST, RIGHT?

Don't worry about the evap test. That checks for leaks in the gas tank and charcoal canister under the car and should have nothing to do with the work you did, save for one vacuum line set and purge solenoid on the intake. Give it a week or two and check to see if it passed. It is a tough one to make run on a drive cycle. Very specific conditions must be met before the test is enabled. Once it runs a couple times, it will either pass or set codes P1456 or P1457. Don't worry until then.

HTH

fsckewe

Excellent. I've had the valve cover on and off a few times. I bought the gasket and some RTV back when I started all this. So if I need it, I have it. No leaking as of now.

So, the gentleman I talked to said he reuses the intake gasket. The gasket that fits between the injector base and the head. And I quote "if it stays attached to the head when I take the intake off, I leave it." But like I said, the gasket itself was clogged, and the big rectangles behind the egr holes in the gasket needed cleaning. I HAD to remove it. And replaced it since I had it out. Is that a little more clear? I simply wanted to ask if you had a take on it.

So, what I am asking is.... the gentleman I spoke to said he leaves/reuses the gasket because it is often hard to reseal the intake with a new gasket. Is he talking bullshit, or do I need to test for a good seal anyway. With eyes and ears I do not notice or suspect a leak, and I torqued everything to spec.

Excellent. And as always, you've been very helpful. Thanks man.

ezone

As long as it seals again it would be fine. I reuse the steel gaskets a lot in various places on engines, especially if the job has to be done in the same day. We don't normally keep most stuff like that in stock.

For the job of cleaning EGR ports on the older V6 engines (Accord and Odyssey), we pull the upper plenum. Never replaced a steel plenum gasket. Honda didn't even pay for the steel gaskets when doing the job under warranty, so it must be good enough. The kit DID come with the paper gasket for the throttle body though, but it does not get replaced unless it tears. They really suck to scrape off.

A flat steel gasket between two chunks of cast aluminum normally seals again without a problem....as long as there is only manifold vacuum being sealed (low pressure situation). I won't try to reuse steel gaskets that have to seal coolant, at least not without using some sort of sealant on them.

I also will sometimes reuse the paper or fiber gaskets IF they don't tear (see above). If it tears during disassembly, it needs replaced.

I guess the choice to reuse really depends on the situation though.

I have even reused head gaskets successfully, but that's a real no-no and was a unique situation. *I* assumed the responsibility if it didn't work.


*I* never had a problem getting the flat gaskets to seal during head gasket jobs, but I just replace during the job since it is part of a head gasket set.

If you don't have a reason to suspect leakage (noise, idle speed, codes), it is probably fine.


Does that answer your questions?

You're welcome.

fsckewe

Sure does. Just wanted to hear your take on it.

I think that closes this out. Thanks for your time, patience and great advice.

ezone

You're welcome.