Whats up everyone? I'm having the unfortunate pleasure of finding out what caused my P0400 (EGR Flow Malfunction).

Things I've done:
Cleaned Intake Manifold and EGR passageways (upper & lower)
Replaced EGR Valve
Now checking for vacuum leaks

Working with basic tools what is possible to check? I dont have vac gauges or a stethoscope.

What she's doing:
Very rough idle
Low engine speed while driving
Engine stumbles on acceleration
Drinking gas like crazy(maybe b/c of a vac leak and running lean)

99TL 253k

Need your help. What else should i look into?

 

Somebody more knowledgeable will chime in. I'm glad you asked this question as I was giing to do this today. Did you let the IM dry out in the sun?

 

well I never used water just lots and lots of carb cleaner. Hasnt really been warm enough to dry outside so i blew out what i could manually.

 

new gaskets on the manifold and egr?
also was it an OEM egr valve?
then you say you cleaned the lower IM passage, did you stick a coat hanger down it, cause sometimes the only way to clean stuff is by mechanical means, not just chemicals (which can do it, but it takes a while though, and sometimes many applications)






also a little water in the manifold is not going to hurt the engine, biggest thing is keeping the engine from hydrolocking, from having too much water in the manifold; so as long as you get the majority of it out, you should be good







heres one though, when was the last time the O2 sensor was replaced?, might be worth a shot, because the ECU depends on that sensor's feedback for if the egr system is flowing properly (it looks for the exhaust gases to lean out some, when the egr is allowed to flow, since it is displacing some of the fresh air that would other wise be coming through the TB)
and i have replaced a couple of O2 sensors, and customers have said the vehicle felt like new, because it became so responsive, had additional power and such; BUT a check engine light was NEVER on, they just complained about the driveability issues

 

same question- did you run the length of the manifold with a wire rod/coat hanger to push crud out-- the single egr port on 99s

rinsing: 3 cans carb cleaner leaves a lot of residue,,did it just run out with manifold placed on throat/intake end?
Blew out manually--like the leaf blower or compressed air source?

how are the plugs?
ckd codes?
did you clean the iacv on TB while it was apart?

I have a gut feeling its O2 sensor by this many miles

 

check the plugs too (also are they NGK brand ones?); or even replace them if it has been a while


also for that O2 sensor; OEM, or a direct fit Denso brand one, is the only way to go, even if you have to wait for it (have had too many issues with the Bosch brand ones, even the direct fit ones)

 

of course- some seafoam may help if the egr was plugged- there is probably carbon loading on the entire internal system--use vac port or TB throat method and gas tank

but there is more to this than carbon- OP more details of why you decided to do the egr cleaning now?

 

BG intake manifold cleaning, along with some 44k in the tank

 

let me clarify: seafoam wont clean the egr by itself~

if the egr is clogged- its reasonable to think other critical systems are too
ie: dirty injectors (causes sputter spray instead of mist), intake valve stems and seats (which affect airflow directly into cylinder and sealing of the valve when closed)
while crudded piston tops alter compression and offer poor ignition area.

for tools; Harbor Freight tools has the vac guage/1 man brake bleeder kit for 25$ and the stethascope for $5
A length of clean pinkie finger sized hose helps locate air leaks
Carb cleaner sprayed at hose connections- with engine at idle- will find vac leaks- when speed increases you hit a leak

 

ok fries--bg or seafoam--whatever the viewer chooses

 

I pushed as far as i could with a wire hanger. the ports twist and turn and it makes it kinda difficult to get far but its clear going up to the im. the other port below the egr valve itself i assume is for vacuum right? i sprayed the crap out of it and pushed the wire as far as i could on that too. Never done the O2 sensors. New plugs were done about 25k ago. Think that could be a problem? No new gaskets as of yet. i followed the DIY on the EGR clean and spacer install and it said to reuse unless bent/broken. IACV has been cleaned and when disconnected changes idle.

Ive gotten a P0420 before but it just went away. That was at least six months ago.

 

Well I got the code a week ago and Ive seen the threads so thats why.

 

Seafoam has always worked for me. Never tried BG.
Nothing has been said about vacuum leaks. Ihave a new valve. Maybe it isnt getting the proper lift??

 

Thanks alot. Ive seen these methods around on the web and even tried carb spray at hose connections and couldnt find anything.

And i look at Harbor Freight for the vac/brake kit. Ill need that for another upcoming project.

 

maybe a plugged cat?, which happens to having too much egr gases flowing into the the intake manifold (since the code does not say specifically insufficient flow, but just that the flow is incorrect from the programed values)



also on the coat hanger going into the lower IM, if inserted far enough, you should actually be able to see the end of it (after you get all the way through), under the egr valve if you were to remove that at the same time

as far as the port going into the block itself, kinda have to play that one by feel/sound; are you hitting like a wall of aluminum or cast iron, and not just a wall of carbon built up in the passgae

 

new gaskets? as mentioned, i know people say they can be reused, but not always though, even if they still look good

shit, head gaskets have a very similar construction (multi-layer metal) as to the manifold gasket, BUT NOBODY normally recommends reusing them ; just saying




also the egr getting proper lift, probably is, since it has a "lift" sensor for the ecu to read, but it may not flow correctly at a specific lift; which is the reason for the question of it being a new OEM Honda egr valve, and not an aftermarket one (btw on aftermarket GM's egr valves, you actually have to insert a calibration washer into it, otherwise it will not flow correctly for the specific engine/vehicle)

 

when i cleaned the ports i didnt see the hanger out the one going to valve i vacuumed out and it has really strong flow. the other one i dont know. i cleaned it as much as i could.

it wasnt an oem valve. i picked it up at autozone. made by bwd automotive.

sorry about the "lift" comment. upon reading the valve is pcm controlled and not vacuum, so:
1. the computers not seeing the right input from the valve
2. or the o2 sensors are messing up the mix

Is that right?

 

have you tried an ecu reset-- just because?

what plugs are you on?

 

If you can use a shop vac to ck flow thru all the passages- thats great!
suck up crud from lower section if applicable

 

253,000 thats miles right? go to a muffler shop and ask for a cat ck
they test internal pressure and temp

by now its very possible to be clogged
just happend to another ziner,,might be this weeks problem of the week?!

 

Ecu was reset when new valve went in.

I think im dealing with a cause and effect situation. Normal troubleshooting thinking leads me to believe another condition caused the egr to malfunction.

I read some info on the web of similiar problems and it pointed to coil pack failure. Maybe it wasnt total failure b/c no code was present but the cel intermittently flashes. In the morning im gonna try and locate a bad coil and take a look at the plugs too

 

you are getting a flashing cel- or some other post you read?

go get the cat checked--its usually free at muffler shops
work smarter not harder!

 

NOW we are getting somewhere...


btw flashing normally means a misfire, and the ecu is trying to protect the cat from further damage (which it can do for short period of time, but not repetitively though)

 

Codes are clues and not he actual diagnosis....
Should be part of the diy'ers bible.

01tl4tl...i will look into the cat check. Won't hurt with this amount of miles.

fries...maybe i should have said that in the beginning...... be patient with me, ive lots to learn...

 

Okay here we go.
Pics.....





Thats the plug from the front drivers side.

And the rest of them...



Comments welcome.

 

Hopefully its something this small.....

https://acurazine.com/forums/showthr...ight=oil+plugs

 

sometimes giving all the info/history of the car, will speed up the diagnostic process alot of times, so what has been done to it previously and such can be taking into account (along with a failure and cause effects that can happen; SUCH as an example, worn out spark plugs, causing too much unburned fuel going into the cat, taking it out over time; or a o2 sensor that is out of range, but still not flagged by the ecu causeing an improper mixture to get to the cat; just using them as examples, because they are some of the easiest ones to explain, even though you may actual have the same issues idk yet)

 

not seeing that, you be seeing the oil on like the hex section of the plug and such, they are too clean on the outside sections

 

also on that front driver side one (cylinder #6 btw)


did you recently spray the carb clean down the egr ports? cause that is the closest one to the egr passages



also does it kinda smell like gas, oil, carb clean, or something else, cause normally the smell will be lingering on it still







if gas, i am wondering if either that coil is bad, or maybe you have an leaky injector (excessive deposits possibly; especially if cheap/bad gas is run on a regular basis) on that cylinder; which is then causing too much fuel to go into the exhaust, giving false readings to the o2, causing all the other cylinders to lean out some, since the O2 ONLY reads the average of ALL the cylinders, and because that raw fuel has been going into the exhaust for a period of time, it has plugged your cat up some, causing the EGR codes to set from excessive backpressure in the exhaust
basically another possible cause and effect situation, that could have happend; cause cats can last a VERY long time, if they are not worked outside their designed parameters; IE: the engine is kept in good running order, and any codes/check engine lights are taking care of promptly (or at least checked to see what it is)(even if they do go away)

 

yeah i went to town on the egr...like 3 cans. the plug smelled like oil.

 

compression test that cyl and the one next to it- to compare

looks like coil failure led to fouling,along with recent egr cleaning may have left residue that went into cylinder

assuming you installed new plugs- swap coils -reset ecu and ck plugs after driving
Does the problem follow a coil?
Note- let engine cool before installing spark plugs- heat- aluminum-steel= wrong torque, stuck plugs

note on that thread you listed--from 2007- it says FILL the cyl with oil for wet test- thats wrong--only a few squirts from a small oil can to see if that gives enough seal to raise compression on low cyl--tells if rings are good

 

The EGR system is fairly self contained and passive. Putting it in other words, it only affects (reduces when working) the NOX levels at the tailpipe and either blocked or unblocked it does not affect engine performance in any other way. If cleaning the port does not work, change the valve which is only two bolts and a conector.

Now it won't sugar coat this, oil on a spark plug is a very serious matter. I would clean and reinstall all the plugs and run the engine again. Then, remove that one plug and look to see if it deposited more oil. I would then do a compression test, but none of this is going to be good news if you still see oil on the plugs. You should have also seen your oil consumption go up in recent times.

The rest of the plugs look fine to me, but the one with oil on it makes me shudder.

Good luck and keep us informed.

 

if the egr passages/ports are clogged and the valve still opens as it should at all times except idle and full throttle- where it would have really bad effects--
Then the pressure of gas backup in the system can lead to other problems
thats what I meant
Should the valve be open at idle,,,,, big problems

I agree the plug is scary- thats why I suggested new plug and coil swap-
reset ecu at clock fuse- test drive
do a plug reading again and hope it was just fouled or you found the reason behind the cel-coil

 

He could also have a bad fuel injector causing excess fuel to go into the cyl. What i would do is swap that injector to a different cyl drive it a while and see if the wet plug is following it.

 

(should have read this pot before posting mine) Check what it smells like. It could be a bad coil/plug not firing right or a bad fuel injector.

 

After a trip to harbor freight this morning...

Compression test went as follows...

160__160__173

171__154__151

#6 cylinder is where the wet plug went

my next diy will be the valve clearance diy. thanks to phee and others i think its something i can handle. picked up the feeler gauge this morning.

01tl4tl...i couldnt find the go-no-go one, so i just picked up the blade style ones and a spark plug gap tool as well.

my next question is does this sound like a gasket issue?

 

did you try adding a few drops of oil to the cyl and retesting?
test conditions? full throttle held open? engine cold?

go find a go-no go feeler guage and make your life much much better on valve adjust

new ngk plugs come properly gapped-that gap spec is part of the number designation

as long as the cardboard is on the tip its ok--unless obviously smashed down~

 

that was a dry test done after a drive to warm the engine up. after my appt this afternoon i will do another dry and a wet test also

 

a little low, but not horrible though for #5 and 6

 

Yeah fries I dont think I did as many cycles. My battery was getting low.