Still P0401 after cleaning egr !! should we drive it?

I will double check everything today but can not hear a leak, I figure that would be audible? all gaskets are on properly sealed and tight, I'm pretty pedantic lol unless it's the eBay catch can? I am almost certain the cans not leaking but could that potentially be an issue or would it be a different code?

my thoughts keep going back to my original findings of the gasket between cooler and exhaust manifold only fit via one stud and as a result restricting the path of flow around 50%, I guess the car was like this for 3 years since engine was installed by previous owner, could this possibly cause the exhaust manifold pipe to block up? (although I could not see any blockage in there from up top) there is a couple tight turns and elbows in that pipe

Been thinking, why would my exhaust pipe block when lots of people get completely blocked coolers and it never seems to go any further, the only thing I come up with is plugged coolers generally start from the intake manifold and find it's way down to eventually plug the cooler, however this potential exhaust manifold blockage started near the misfit gasket at exhaust manifold pipe on an otherwise clear system.. thats the only difference I can think of?

I don't know what to try next but have been contemplating what's the easiest way to check the damn exhaust manifold, remove exhaust manifold completely or just pull the cooler again and disconnect exhaust pipe from the flange (as to not push any crud through to cat)

I don't want it to be the exhaust manifold tbh I really cbf doing this job lol but unsure where to go from here

Thanks again, please post an easy fix that will take me 3 minutes to do

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Hey Wheezyglider .. mate its never too late for coffee!

yeah its strange, trouble is i do not know how a faulty valve might look on techstream, we can see the MAP doing its thing once the valve is ramped up past step 24 so im with your thoughts on the MAP being okay but i do not know what a "lazy" stepper motor looks like, basically i think its down to two things either bad/lazy egr valve /motor/magnet or its still blocked, which points towards the manifold

The misfit gasket was found prior to cleaning, its not like that now! basically a couple weeks ago i got P0401 one hot day driving up hill with a loaded car and when i took it apart to clean everything i found the gasket between exhaust manifold and cooler was not correctly fit and restricting flow around 50%, didn't think too much of it at the time i just took off all egr bits cleaned everything and reinstalled with a fresh gasket and catch can, i am no stranger to spanners and its my own car so made a conscious effort to get everything neat tidy sealed and proper!. Nothing was really that "blocked" to begin with .. and FAIL. stil P0401

Pretty sure i am down to either still blocked somewhere which seems the most likely as i have similar test results to what people get BEFORE they clean the entire system, or a faulty valve which i do not know enough about to really guess if its the problem

The only solid thing i have to go off is the fact my system was never blocked to begin with, yeah it was a little dirty but not blocked enough to cause P0401 so its been something else from the start!

just wish i could source another stepper motor magnet to try, its so much easier to try than removing cleaning the manifold

im hearing you about the cat eating carbon for lunch however it still wouldn't be great to send through 100,000km worth of crud in one big black package lol, its going to have trouble dealing with that much crud in one hit and will almost certainly cause a big black nasty patch on the entry mesh

closing note! .. the car has been driven for 3 years /100,000km with the egr 50% restricted where the cooler meets the exhaust manifold, i guess that junk has to go somewhere!

 

Hi Chapman, firstly thanks again!

This all makes sense and I agree its not likely to skip multiple steps then just come true at 24, would be nice to know what sort of behaviour to expect from a failed motor/ magnet, maybe they get lazy or do they just completely stop stepping all together, if anyone knows please chime in!

Can I ask, are you suspicious of my exhaust manifold being plugged?

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It would be an interesting test however I would need to strip the valve back off the car to do it as can't see the valve position in situ, and count on the fact the bench test is relevant to real world use, my luck it would test fine on the bench just to throw me off! Wish I could find a rotor aka magnet to try on car that would take 5 minutes and pretty much cancel out the valve /motor from the equation however unfortunately I can not find a good used valve locally and a new valve in Australia is literally half the value of my car! a decent outlay considering it's not overly likely to be the problem.

The egr cooler, piping and valve are definitely clean, so .. guess I should cancel out the manifold (lots of swearing & moaning)

Wonder if I disconnect the cooler from exhaust manifold can I wiggle it out enough to access the exhaust manifold pipe without actually removing the cooler (or manifold) and disconnect the cat under car.. and clear the pipe with exhaust manifold still in situ

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Will compare them if ever lucky enough to get the two next to each other however im having issues finding a good used valve, this one "wrecking yard" quoted me $660 for a used valve lol what a bunch of jokers hey! bloody ripoff merchants, I can get one cheaper brand new through the local dealer..

Update !!! .. i took the time to pull the exhaust manifold today aaaaaannd....... its perfectly clear! .. minimal contamination

Definitely didn't miss any part of the system when cleaning, i am known for my pedantic nature when it comes to these things, i wasted two cans of oven cleaner, 2 cans of brake cleaner, two cups of oxi cleaner, two brushes and about 10 hours of my life cleaning that stuff, like three times! its clean ..

 

anyone have a spare valve they would like to sell? With postage to Australia

I took the exhaust manifold off from under the car as I really didn't want to take the cooler off again if I didn't have to, couldn't get the manifold out past the drive shaft so visually inspected the pipe from both ends, punched some compressed air through it and put it back on

I am keen to bench test the valve but even more keen to just find a stepper and magnet to try, have been piddling around with this thing for too long im running out of mojo with it

From memory it's near impossible to get the nuts between valve and cooler off without removing the complete cooler, although I did not have any trouble getting the cooler to exhaust nuts undone from up top yesterday, definitely no need to remove wiper cowl for those two nuts, please remind me what is the reason for removing the wiper cowl? I removed it when doing the job because the video told me to

So how about it who wants to send me a valve lol I will settle for just a magnet and motor )



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Please send me that spare egr valve you don't need it.

Hi Mendel .. yeah it opens things up I guess, I have only undone the two cooler to exhaust nuts with cowl on which took perhaps two minutes however I can not comment on what the rest of the job might be like with cowl on, its probably just easier all round to remove it I guess

I did leave the bottom cooler bolt out because it's a pita, not sure about free spanning the whole egr only support being manifold to manifold, I mean it's probably okay but my ocd would insist on fabricating some sort of simple bracket system in the middle somewhere, mostly because I'm annoyingly pedantic

egr valve on 4th gen looks similar to 3rd gen just with an extra cooler line, wonder is the stepper motor and rotor/magnet part the same





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