Check engine light on my 99 SH -insufficient egr flow (think it's p0401)keeps coming on-changed the valve, cleaned out the intake ports, it's still throwing the code. Next step Honda recommends is changing the ecu, however don't think that's the problem-the light comes on fairly consistently on trailing throttle (coasting downhill, slowing for toll booths, etc), think it would be more random if the ecu was acting up, also takes a few days to come back, or a few hours at freeway speeds. Car also has cat back (NOT recently installed)-could that be the problem-insufficient exhaust pressure to create enough egr flow, helped along by aging or something else. Any help appreciated, I'm stumped and don't wanna buy a new ecu if that won't fix the problem, spent enough already.

 

Isn't the EGR relate stuff under an extended warranty? 8 years?

 

Don't think so, took it to the dealer once because the ATTS light also comes on with CEL, they didn't offer to replace the EGR for free.

 

Sounds to me like the EGR ports in the manifold are blocked. Insufficient flow means just that.

 

Yeah, that would be the obvious answer,. except that the mechanic has cleaned them twice, code keeps coming back. Apparently there's no sure way of cleaning/checking the ports without removing the intake manifold, is that true?

 

Yes.

 

removing the intake manifold really isn't that horrible. It does totally suck big ***, but its a 1 night project tops.

Ill go over a few quick steps to get you started.

Make sure you have all basic hand tools/ratchets etc.. Also have a bottle or two of carb cleaner handy to clean the entire intake manifold and TB while everything is apart.

1. Disconnect negative cable on the battery. Pull it completely off the terminal.
2. Open the fuel door and pull the fuel cap off to relieve fuel pressure.
3. Have a rag handy and loosen the banjo bolt on the fuel rail and catch the excess fuel. ( WARNING DO NOT SMOKE AROUND THE WORK AREA DURING THIS STEP)
4. Take off Intake arm, and make sure to label all vac lines or have a print out of the vac diagram.
5. Disconnect the IAT,TPS, EGR, injector plugs, IACV and its coolant lines.
6. Take off the throttle cable and be VERY careful not to kink or bend it.
7. then its all about getting to all the IM bolts to get the thing off. This is the part that is really going to suck
8. There is also a bracket underneath the IM that is pretty difficult to get to. Good luck on that one.

When you finally got everything lose the IM slides right off. If you can take it off without damaging the gasket more power to you, otherwise its going to need to be replaced. When i was cleaning my IM i just took the whole thing apart and blasted it all with carb cleaner. My IM is so clean you could get a chicken dinner off of it. Just take your time, label all hoses or have a helms handy. Helms manual can save your life. Also, plan ahead!!!! get all necessary gaskets and so on BEFORE you take everything apart. ( if you do in fact decide to take the im off for cleaning.)

Remember, this is my personal experience. I am in no way a certified Honda technician and not responsible for any damage incurred by following these steps. ( its really a simple task as long as you are mechanically inclined)

 

Many thanks for the help, guess I'm gonna havta bite the bullet and do it, what about after market im's, see you have Skunk2 for sale, whatr they like?

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by 98TypeSH &raquo;</TD></TR><TR><TD CLASS="quote">removing the intake manifold really isn't that horrible. It does totally suck big ***, but its a 1 night project tops.
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Remember, this is my personal experience. I am in no way a certified Honda technician and not responsible for any damage incurred by following these steps. ( its really a simple task as long as you are mechanically inclined)</TD></TR></TABLE>
Sorry for resurrecting a slightly older post - but you said you did this on your car, and you have an SH model? So you can get to all the lower IM bolts without pulling the ATTS?

Thanks . . . .

 

Yes you can. Its a bit difficult and takes quite a bit of time. I switched sockets/extensions used open ended wrenches and 1/4 turn or as much as i could turn them at a time. I even dropped 2 of the bolts and spent a few hours finding them lodged in some odd places. I found it easiest to stand on the top rad support, put both knees on the valve cover, put your arm under the IM and do the best you can. with some patience you should be able to get them. Be creative, use the ol noggin Its physically impossible to get to the IM bolts from the bottom ( at least on an SH )

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by 98TypeSH &raquo;</TD></TR><TR><TD CLASS="quote">Yes you can. Its a bit difficult and takes quite a bit of time.</TD></TR></TABLE>
Sweet . . . . sounds like fun.

Hopefully I'll be able to clean out the EGR ports with some pipe cleaners & a wire brush well enough to satisfy the computer, but it's good to know that I can get the IM off if I have to.

 

i dont believe its recommended to spray the carb cleaner or any other solvent directly into the chamber ( while its attached to the head ) as it does lead into the compression chambers. There could be some debris that you would wash into the chamber. that = not good.

 

Make shure you dont break the KS... I did this 2 times..It cracks in half VERY easy..