Rep Power: 0

I just bought a 2002 Civic ex with D17A2 engine and it keeps throwing code p0401: egr insufficient flow, I already tried cleaning the EGR valve and cleaning the ports underneath, cleared CEL and it's still throwing the code. I pulled the EGR valve off and started the car and it did not stall telling me that the ports in the head are clogged. Can someone please give me a detail instruction on removing the fuel rail and intake manifold so I can clean these ports? And a good method of cleaning these ports would be nice to. Thanks!

 
Rep Power: 267

I just pulled off the intake manifold and water passage as part of replacing the head gasket. You can follow the procedures for the head gasket to just get to what you need. I couldn't believe how much build-up I had in the intake manifold flange and the water passage.

I assume the build-up is from recirculating the exhaust air through the PCV, is this correct? Is the PCV bad to allow the build-up? How do we keep it from happening again? I have 145k miles on the car but the intake manifold flange and water passage were almost completely clogged. Is this routine cleaning or is there something to prevent it from reoccuring?

 
Rep Power: 811

do you take the pcv valve off each year and spray with carb cleaner?

 
Rep Power: 267

I will now. Just to make sure I get it all, the PCV flow comes from the breather which is on the block, then goes into the intake manifold flange. Does the flow into the intake manifold distribute to all of the ports or is it just dumped into the end?

Then there is gunk flow out of the cylinder head thru the intake manifold flange back into the intake ports. Then there is flow from the end of the head to the water passage for the EGR, then back into the head. These are independant from the PCV. What are they and why are they so dirty? Is it all blow-by air? Confused.

 
Rep Power: 811

i think they are separate systems. pcv vents the engine gases and reburns them thru the intake mani. egr takes exhaust and sends some of it back to cool the cylinders and reduce NOX emissions thru the head passages. not sure why they would get so dirty, best guess would be all the carbon that gets deposited everywhere. same reason the TB parts get gunked up from blow-by. i havent checked mine and dont think you can even clean them without removing the head. maybe by sticking those thin pipe cleaners in the passages. The pcv normally should not be that dirty unless you do a lot of short city driving and the engine cannot warmup.

 
Rep Power: 267

Yeah, I just read in the service manual about the EGR. I had the flow backwards since it is recirculating the exhaust air thru the EGR into the intake manifold. So this line will always be getting covered with soot.

Question gb: looking at the amount of soot in this line - shouldn't the FPplus help reduce the amount of carbon deposits? Or should it actually increase it since it is cleaning the valves? I have been using the FPplus religiously for 3-4 years now. The buildup may have been before using it, but the passage thru the intake manifold flange was about 90% blocked. Just wondering if it is helping gas mileage but clogging the EGR.

 
Rep Power: 811

the fp/lc additives (i've been using over 5 yrs now) dont really do much as far as changing the way the engine operates. the fp keeps the fuel system parts clean, and the lc keeps the engine internals clean. combustion engines are still very dirty things and no amount of additives and oils will help that. and technically those passages you mention are not part of the engine where the additives would ever reach. when i first had the car and was not using any additives, i noticed massive gunk all over the intake related parts. but after additives and cleaning the parts, i havent had to clean them even once since then. i looked a few yrs back to see what happened, but everything still looked brand new like i just cleaned it. i do the pcv every year but there is never much of anything to clean. so ive stopped doing any of the stuff i used to in the past cause its a waste of time. one thing i havent checked are the egr and pcv ports like you mentioned. i did notice there was quite a bit of carbon soot in the ports when i cleaned the egr valve, but couldnt really think of how to remove it. not chunks or anything, just a layer of smooth black. i must say this about the fp/lc additives...before i used them, my oil would turn black after a few weeks, telling me there was serious stuff going on in there or massive buildups. today i go 10k miles or about a year on each oil change and i almost feel bad changing the oil that soon. it looks almost like new with a light brown color. i even did a one time LC20 engine flush recently by pouring it in and letting the engine idle 10 mins before changing the oil. i doubt it needed it, but i wanted to use up some more of that old bottle i still have so i can order a fresh one. engine internals look brand new when i peek in the oil cap. so yeah i would say the additives def made a huge difference in how clean the motor runs compared to before when the car was only a few yrs old.

 
Rep Power: 190

EGR passages should be in the head but not accessable to clean through any ports that I know of. It travels from exhaust through head, to water passage, through EGR, back into water passage, then through head, into intake... I think. There's no real diagram, so I'm just guessing.

Without pulling the head, I'm not sure of an effective way to clean those passages.

 
Rep Power: 811

i always worry about what would happen when chunks of stuff you loosen get sucked into the engine....

 
Rep Power: 0

Drill out the ports the carefully, clean the ports using the good cleaner. tap ports, you also have to remove the metal shavings, so for that you have to clean more. Close the port bought from the hardware store. You will find it very simple, and this is how i did with my h22 manifold. Just find the right bolt and that all will be set. I think of 7 bolts.