EGR ports

Fourth Generation Honda Prelude topics

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Tallrunner68
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EGR ports

Post by Tallrunner68 »

Ok, new here, but I did search and have looked at the manual to no avail. While I have my TB and off to clean it and the fast idle I wanted to clean/replace the EGR valve and the fuel filter. I was hoping to be thorough and also clean the EGR ports. Did my reading and watched a few videos, but checked under the hood and realized that I didnt have the plugs. I have what you might call ports, the raised circular portions on the intake, but no plugs to drill and remove. It looks like they have been welded over. Its the H23A1 and I was expecting the plugs, having read somewhere that the H22s might be welded, but not the 23. At this point I am confused on what to do next, do I drill the welds and put my own plugs back in? Are there plugs beneath the welds? More research is required and I will double check the manual once more, but if anyone has previous experience and a solution I would love to hear about.

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spiffyguido
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Re: EGR ports

Post by spiffyguido »

Hmm...having trouble figuring exactly what area you're referring to. Are you trying clean the ports for the EGR valve itself? Or something else? Pics might help.

In any case, the EGR valves I've seen have been bolted on, so I'm uncertain why you might have some welds. I must be misunderstanding what you're trying to clean.

Tallrunner68
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Re: EGR ports

Post by Tallrunner68 »

I may have looked at the wrong manual. I got the information off another website, and i am quickly learning that they are not always as accurate as this one seems to be. But, Honda does have a replacement kit just for this application, EGR Plug Replacement Kit: P/N 07WAZ-001000A. But it may be for the 5th gen prelude. Essentially, i am wanting to clean the intake manifold as i doubt it had been by the previous owner. On some of the engines it would seem that there ports available to do just that, without having to completely remove the manifold from the engine. But it is looking like my best option is to totally remove the IM and do a thorough cleaning. Hopefully all it will cost me is the replacement gaskets and the time to do so.
Attachments
This seems to be an exert from a Honda write up on the subject, but i suppose it may not apply to my engine.
This seems to be an exert from a Honda write up on the subject, but i suppose it may not apply to my engine.
Port pulling.gif (11.4 KiB) Viewed 25418 times
These are what my ports look like
These are what my ports look like
These are the ports open and cleaned from another thread on another website.These are what my ports look like
These are the ports open and cleaned from another thread on another website.These are what my ports look like

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spiffyguido
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Re: EGR ports

Post by spiffyguido »

Wow, I've never heard of anyone doing this, so I'm learning something new. I hadn't understood what you meant. I thought you just wanted to clean the place where the EGR valve bolts on.

Now that I see what you're referring to I can understand the issue, and yes, many Honda engines I've seen have the plugs blocked off as the ones in the picture are. I've never heard of anyone drilling them out, but if you did do so as the manual suggests you'd want to be very sure to clean everything up very nicely afterward. Don't want to leave anything behind that might end up in the engine. Seems like the type of thing that would easiest to do with the intake manifold removed.

If you decide to do this, I'd very much like to see pictures of the process.

Tallrunner68
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Re: EGR ports

Post by Tallrunner68 »

After more searching it looks like the 4th gen have those ports welded over, and there is some debate as to whether or not there are the brag plugs found on other engines are under those welds or not. I have the Honda gaskets ordered for the IM and am probably going to just take it off and clean it that way. Not real fond on drilling into my IM without personally consulting a Honda Tech. So last night i went about labeling all the fuel/vacuum/coolant lines for the entire IM assembly and hopefully will be able to get it off this weekend. Though i have heard horror stories about trying to remove the old gaskets. I just hope its not too much trouble for the benefits i hope to reap.

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spiffyguido
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Re: EGR ports

Post by spiffyguido »

The gasket will probably come off pretty easily. The intake ones are usually a paper composite, so even if it sticks it's easy to scrape off.

Tallrunner68
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Re: EGR ports

Post by Tallrunner68 »

Stopped by my local scrap yard to look around today, and found a few items I am interested in. One of which is an intake manifold off an unknown year accord. Its an F22A1 engine, and has the stock EGR access ports for future cleaning that I would prefer. As I understand it, there are parts that are cross compatible between the H and F series engines. What I dont know is if the IM is one of those. Anyone with any experience with this sort of thing?

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Re: EGR ports

Post by spiffyguido »

Wouldn't be surprised if it fit, but I doubt you'd want to actually put something like that on your engine. Your H series engine will have larger runners likely, and I believe the injectors are positioned differently on an F22. I wouldn't make that swap, even if it does fit, for the simple fact that the H series manifold is likely superior.

Tallrunner68
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Re: EGR ports

Post by Tallrunner68 »

I was afraid of that, I found a few threads comparing everything but IM. Could not find an H23a on the lot, I would like to attempt the drilling of the EGR ports and tapping new threads, but also dont want to attempt it without a spare. Bigger fish to fry at this point. After bleeding the brakes they feel a lot better, however still getting ABS light. Jumped the plug to get the code and apparently its the ABS pump motor. Havent cleared the code yet by pulling the fuse, maybe once I do it will turn off with new clean brake fluid and airless lines. If not I will begin looking for a compatible donor. I found a thread on cleaning the motor and possibly returning functionality. Estimated Honda repair is $800-$1000, so willing to at least try it first. Just throwing that out there before I get the "only let a Honda Tech service ABS" I understand the risks involved, but weighed against the price of service (more than I paid for the car) I am not ready to make that investment.

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RedRacer
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Re: EGR ports

Post by RedRacer »

A few years back, before the engine in my Prelude committed suicide, I had some interest in the same thing - wanted to really clean things up and out and see if there was any noticeable performance improvements, i.e. better mileage, less tailpipe emissions, smoother idle, etc. I wanted to do the same as you, tapping out the ports (mine look exactly the same as your picture shows) - I took it to my trusted mechanic, the guy who built my engine, put on the turbo, etc. and he said, and I quote, "NO, leave it alone!" Said unless there were severe performance and running issues, that was not something you really want to do.

Been working with this guy for many years, never steered me wrong. And, he was trained by Honda in Japan, he knows his stuff.

It's up to you entirely, of course, but I never gave it a second thought after he gave it a thumbs down.

If you had a donor IM that is functional and in good condition, I'd go that route, work on it (OFF THE ENGINE) and see what happens. If it's turns out to be a disaster, put the old one back on and pretend it never happened. ;)

Good luck!

Tallrunner68
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Re: EGR ports

Post by Tallrunner68 »

Yes, those are my thoughts exactly. I am not really comfortable doing it, but if i can grab a spare IM from my local scrap yard for $30 then i am willing to experiment with it off the car. I have seen the ports on the cars that do have the access plugs and they are always filthy. I cant imagine that is good for the engine, or my gas mileage. My scrap guy is really cool, you pull the part yourself so it is discounted pretty nicely. If i can find an H23a intake i will give it a go, possibly an H22 if they are compatible. Performance is not my biggest concern as much as gas mileage, but i will probably avoid the F22 as per Spiffys suggestion. Much difference between an H22 intake and an H23a?

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Re: EGR ports

Post by RedRacer »

You're thinking the right way. If you can find one that you can play with, I'd do it. Always a learning experience if nothing else.

When I say performance, I don't necessarily mean better/more power, so much as I mean more efficient engine performance overall, mpg, smoother running, etc. That was what I was looking to gain with doing this procedure as well.

We have some good you-pull-it yards in my area, but if you don't get there as soon as the donor is brought in, they're stripped in a matter of a day or two. Sucks.

H22 and H23, I think the throttle body is the same, but there is a difference in the VTEC head and mounting, an extra port or bolt hole, I don't remember, and the bolt pattern on the lower side is different too. From what I remember the F22 and H23 are the only ones interchangeable.... but don't quote me on that. And as Spiff said, I'd steer clear of the F22. You don't want to do that, not made for your engine, won't yield superior results.

Tallrunner68
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Re: EGR ports

Post by Tallrunner68 »

Luckily we have a few yards around here. I still havent found the H23 though, but I only covered about half the yard.



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