Engine Strengthening by a4darkness

[a4darkness]

Ah, okay. Gotcha. And pls do, I'm thinking it'll fit perfectly but have not yet gotten around to re-ordering it yet.

I'm kinda kicking myself for this one cause the ID of the valves is closer to 4mm, but everywhere I read "buy 3.5mm ID." Should have listened to my gut on that one.

[PDX04a4]

ya, 3.5 mm ID is always a PITA to get over the barbed ends of check valves/T fittings. i have 4 mm (i think slightly smaller, like 3.9) ID silicone hose that i used to make a section for the N249 bypass. i've always wondered if using a larger ID hose would affect performance in any way, but i might run the ~4 mm ID hose all the way to my DV since im afraid my factory hose is going to rip again.

[a4darkness]

I've seen more than a few posts about using 4mm ID hose sans issue (but obviously can't speak to that myself).

[tapA4]

Welp, I figured I'd post on here the garbage I went through! lol last night around roughly 9:30 I decided to replace the 3 MTC check valves I received from USP. While installing the last one, the valve that's the most noticable..sort of right under the coolant reservoir, I broke the T fitting and it crumbled in all the hoses it was connected to....of course no where that is open at 10pm will carry a T fitting so I had to get up around 6:30 and head to lowes for the part...I got everything right and running this morning before school (thank God). May not sound like it was intense, but believe me, for a highschool whose late to class everyday this was the last thing I needed to happen! Like I said, install is complete..but my car is still running a little rough at idle. I still need to replace the WTF valves next.

[a4darkness]

ROTFAL Awww man, that is funny... but only cause I've done the exact same thing. Nice work on getting it sorted and to class on time! I love it. Glad you posted.

Someone warned me about the potential for the t-fitting imploding upon install so that's why I included it in the shopping list. Probably should have stressed that more.

While I can't specifically speak to the rough idle, as you might have other weak points that have yet to be addressed, keep in mind that the ECU will need to adjust. Took mine a few days before it started correcting itself after I swapped everything. For example, now my idle is DEAD silent. Pretty cool.

Keep us posted!

Welp, I figured I'd post on here the garbage I went through! lol last night around roughly 9:30 I decided to replace the 3 MTC check valves I received from USP. While installing the last one, the valve that's the most noticable..sort of right under the coolant reservoir, I broke the T fitting and it crumbled in all the hoses it was connected to....of course no where that is open at 10pm will carry a T fitting so I had to get up around 6:30 and head to lowes for the part...I got everything right and running this morning before school (thank God). May not sound like it was intense, but believe me, for a highschool whose late to class everyday this was the last thing I needed to happen! Like I said, install is complete..but my car is still running a little rough at idle. I still need to replace the WTF valves next.

[tapA4]

ROTFAL Awww man, that is funny... but only cause I've done the exact same thing. Nice work on getting it sorted and to class on time! I love it. Glad you posted.

Someone warned me about the potential for the t-fitting imploding upon install so that's why I included it in the shopping list. Probably should have stressed that more.

While I can't specifically speak to the rough idle, as you might have other weak points that have yet to be addressed, keep in mind that the ECU will need to adjust. Took mine a few days before it started correcting itself after I swapped everything. For example, now my idle is DEAD silent. Pretty cool.

Keep us posted!

I'm slowly making progress. But I'm getting there. Will do though, keeping all informed. Thanks brother!

[a4darkness]

You bet, no problem.

Side note, I turned post #1 into a summary that way ppl don't have to wade through this entire thread to find the important stuff. Will update it accordingly.

[audballz]

Great Thread!! Maybe include the breather hoses underneath the intake manifold, connecting to oil filter housing?
My T housing (#5 in diagram below) split in half and was amazed to see how much oil crap built up in there.
I'm sure the other hoses near it are also clogged.
Possibly the reason why the T housing disintegrated?
So while I'm in there might as well replace all those hoses and PCV connected to it.
Anyway, I know there's already a million threads on these breather hoses, but I think it belongs here as well.

[PDX04a4]

over the last 2 weeks i noticed my gas mileage get crappy and my acceleration under boost was erratic, plus i was never getting full boost. read around and thought it was my N75, decided to pop the hood yesterday and check around, see if i could find what was causing the problem. looked at the hoses around the N75 and all the hoses that commonly cause these problems, didnt notice anything. i was stumped. then as i was standing there i notice on the back of the engine a nipple coming off the silver combi valve, i thought wtf, i havent seen that before. lean over and sure as shit there is a hose that dropped back down a little bit, out of view. freaking hose clamp must have popped off and the hose came off. hooked it back up, the acceleration under boost is a lot better and my mileage seems about normal. still not hitting peak boost, and my boost under WOT flutters which makes me think my N75 is still going bad.

i hate the vacuum/boost system, so many stupid little things like this robbing me of power. today im going to go grab some more of that silicone hose with 4mm ID and do a couple hoses as well as a brass T for my boost gauge since i think im leaking around there, hopefully it gets a little better.

[tapA4]

over the last 2 weeks i noticed my gas mileage get crappy and my acceleration under boost was erratic, plus i was never getting full boost. read around and thought it was my N75, decided to pop the hood yesterday and check around, see if i could find what was causing the problem. looked at the hoses around the N75 and all the hoses that commonly cause these problems, didnt notice anything. i was stumped. then as i was standing there i notice on the back of the engine a nipple coming off the silver combi valve, i thought wtf, i havent seen that before. lean over and sure as shit there is a hose that dropped back down a little bit, out of view. freaking hose clamp must have popped off and the hose came off. hooked it back up, the acceleration under boost is a lot better and my mileage seems about normal. still not hitting peak boost, and my boost under WOT flutters which makes me think my N75 is still going bad.

i hate the vacuum/boost system, so many stupid little things like this robbing me of power. today im going to go grab some more of that silicone hose with 4mm ID and do a couple hoses as well as a brass T for my boost gauge since i think im leaking around there, hopefully it gets a little better.

Where exactly is the N75? Could you put up a diagram that shows it.....I've heard and seen it talked about but still don't know what it is......

[PDX04a4]

i dont have an actual picture of it, but its a 3 way valve that is connected directly to the TIP. the valve is right below the large hose/pipe that comes off the middle of the TIP (if you have a 2002-2003 a4, its right below the pancake valve). heres a pretty good thread that describes it:
http://www.audizine.com/forum/showth...t=N75+location

[SmurfetteB6]

Ok I know very little about cars let alone Audi and I've had some freaky things happen to my car that I had to have repaired; frm wind shield wiper motor failure crackin my wind shield. Window regulators failure. A shattered Thermostat housing unit. A Hole n the coolant system and I had to keep a jug of water is the trunk to keep her from over heating. There were times I wanted to drive her off the bridge but I would spend what was needed to fix her so my ? Is should I trust the Audi dealership to fix things that r major. My Quattro is workin on 95k miles and I'm a nervous wreck about it. I don't want to have to send her off on a flat bed from my own ignorance although I have learned a lot from the thing me and my A4 have been thru *tear*

[widgget]

My Quattro is workin on 95k miles and I'm a nervous wreck about it.*

95k is nothing and the AWD system having a problem is about one of the last things you need to worry about.

[chris.mcneal]

This is a great resource, thanks so much

[a4darkness]

Tried to cull down my pics and assemble something that would be of use to anyone attempting to make some of these repairs to their vac system. Hope this makes enough sense, will keep it brief.

Keep in mind, much of these pieces can be removed in sections! This will save you from having to wrassle with all the one time clips. Be smart and see what you can remove as a cluster. More on that later.

First things first. Screw down clamps are awesome cause you can always use a driver like this. Makes your life easy.




The red arrow marks the point of failure on my just suction pump. (see my hand in the top right pulling it away) The two red circles are some of the valves in question that need to be replaced.



Keep in mind that all of these parts are flexible and can shift from pic to pic. Once you get under your hood and look around you'll start to see this and they'll become more familiar.

Using a narrow flat head (and pliers) is an excellent way to loosen the one-time clamps. The red circle here is where the three way valve was once connected. (obviously referencing previous pics in post 1 will help)



Again, circles mark valves to be replaced and the square is where the 3-way valve once connected. Also, the large s-shaped black tube at the forefront of the image (that runs to the back firewall) will be rotated over 180deg for room to work. So when you see it later and it's backwards, that's why.



The location of this clamp deserves a special place in hell. It's connected to a small solid pipe meaning it's tougher to get loose.
Here's where using pliers and a narrow driver will come in especially handy.
Even after loosening the clamp, I had so much trouble getting the hose off that I eventually sliced the end open to pull it free.
Since I bought a replacement, I wasn't worried. Keep in mind that the hoses from the factory are tough and won't play nice all the time.





In the circle on the left, you can see the marks from the blade. The hose was really on there. In the center circle, this is where the jet suction pump and friends once lived, off to the right the s-shaped piece that runs to the master cylinder. Be careful bending it around and out of the way. Also, notice the s-shaped tube has been rotated out of the way now.



Top view




Remove this hose from the small silver tube off the back of the block (check the top pic for a before shot) and then attacking the clip at the base. This will allow for a far easier extraction.




I thought this might be particularly helpful. This is essentially the rear vac system (minus a few pieces). Starting to make sense? Hope so. Also, laying the original pieces out like this will make it far easier to rebuild with all your new parts.



This little ****** snapped the tip of my Special Made In China Cutters right off! Guess Germany wins this round. After removing this old valve I put this piece right back in.



Same piece shown. Left to right: connection yet to be made off the silver pipe, new screw down clamp attached to the new, gray (WTF) valve, and again new screw down clamp.



At the top, notice the hose and valve from the previous pic. Dead center, see how pre-attaching a screw down clamp can make reassembly easy. Just tighten it enough so it's not moving around at stays put.



More reassembly tips. Even the small hoses have shape to them. Match up the bends before tightening them down. And angle the screw down clamps for easy access. Makes you realize that most are somewhat specialized and can't just be replaced with basic heater hose (props again to spector/Kegan for trying thou).



Here's a far more assembled pic.
1. attached to silver tube off the back of the block (which BTW does not always appear in ETKA)
1-2 drawn line: didn't have the part number for this so I left the original in place, appeared to be fairly new so I'm not concerned about it.
2. new WTF valve and corresponding clamps
3. difficult to remove hose on metal piece (I used a heat gun on the new OEM host to slip it over the black metal tube - just enough to soften it up)
4. the 2nd WTF valve
5. the US Plastic check valve + new clamps
6. new OEM 3-way check valve and new clamps



Pulling apart the left had size (lost a random clip off the firewall. These hoses were in pretty damn tight.



And assembly of the new replacement piece. Enjoy a healthy snack to celebrate your reclaimed boost pressure and mpg.



For whatever reason I either didn't snap good pics of the finalized assembly. Will do so soon when I swap some of the valves and pieces underneath the manifold.

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[GeoergeA402]

Great pics, and writeup!! love seeing the apple in the workstation and the baseball gloves as work gloves

[a4darkness]

Great pics, and writeup!! love seeing the apple in the workstation and the baseball gloves as work gloves

Before this was wine country.... it was apple country! Seriously, I might be addicted.

The batting gloves were a bit of an accident but now they're all I ever use. Have tried countless times to find mechanics gloves that are as form fitting, have good grip yet still protect my red fountain pen fingers (total bleeder here) but haven't! I keep washing these but sooner or later I'm gonna have to find a replacement.

[a4darkness]

Well, good news and bad news.

Obviously, since my Suction Pump came apart, I've had a nice bright CEL staring me down every time I'm in the car. Since my reg is due and I owe The Man a Smog Test, it needed to be cleared. Fortunately, last night I was successfully able to clear it using the following process:

* MBP running 10.6.4
* installed Parallels 5.09376 (had issues with 6, rolled back)
* installed Windows XP Home Edition SP3
* installed VAG COM v311.2
* using the Alpha-Bid eBay Cable + corresponding software
* when plugging in the cable, chose virtual build not the MAC OS

EDIT: as of 2/12 haven't yet switched to Lion but can confirm success using Parallels 7.0.14922.693916, it's a lot faster too

At this point I was not expecting the cable to work and sure enough it didn't. So, I started looking at the alternative drivers on FTDIChip.com. Tried a few and nothing worked but realized the problem was likely not the drivers but basically their locations and how Parallels works in conjunction w/the Mac.

Realized that an executable driver setup could be the answer... turns out it was. (Yeah, I know... learn2driver)

On this page:
http://www.ftdichip.com/Drivers/VCP.htm

Look on the right side of the Windows driver where it says 'Available as setup executable' and click on that link (also below). File is called: CDM20802_Setup.exe

http://www.ftdichip.com/Drivers/CDM/CDM20802_Setup.exe

Ran this exe file out of XP, restarted and sure enough it worked. Fully functional, no issues.

Cleared the CEL and went for a spin... she was running great!

So today, I headed over to yee ol Smog Test Facility and promptly FAILED!





Why? I didn't put enough freeway miles on the car to properly enable the computer to be ready for testing. So, basically I gotta clock some miles on cruise control to get things right again and go in for a retest on Monday. Pissed about that, but still happy to see that I passed the rest of the tests. Lets hope things work themselves out. <knocks on wood >

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[PDX04a4]

scan it again for codes. you can run the same readiness checks that the DEQ runs when they scan your car, its in vag-com (cant remember which tab). i think you need to run 3 full cycles of start, run for X miles, turn off, before the car will pass readiness. i would run a few more cycles and see what happens, but if the CEL fail continues than you need to find what is causing it with codes.

[a4darkness]

My bad, now that I'm reading your reply the printout seems rather contradictory. There's no CEL or any other faults... all is well in that regard. But, exactly as you mentioned, I didn't run it through the proper cycles. However, I'm getting a copy of said procedure and will post it shortly.

scan it again for codes. you can run the same readiness checks that the DEQ runs when they scan your car, its in vag-com (cant remember which tab). i think you need to run 3 full cycles of start, run for X miles, turn off, before the car will pass readiness. i would run a few more cycles and see what happens, but if the CEL fail continues than you need to find what is causing it with codes.

[a4darkness]

Wanted to be sure and post the procedure to ready an ECU for an emissions test after clearing out codes. When you wipe codes using Vag Com, the car + ECU need to perform certain basic functions to get back to normal.

Big thanks to audinaut (AZ) aka javanator (QW) for providing this for us.

Audi > A4, S4 > 2002-2007 1.8 Liter 4-Cyl. 5V Turbo Generic Scan Tool, Engine Code(s): AMB ST - Readiness Code
Readiness Code Description
Diagnostics are performed at regular intervals during normal vehicle operation. After repairing an emissions related system, a readiness code is generated by road testing the vehicle.
If a malfunction is recognized during the drive cycle, it will be stored in the DTC memory.
The OBD drive cycle operation will be monitored with a hand held diagnostic tool. Consult the manufacturers instruction manual for correct tool operation.
The readiness code is erased every time the DTC memory is erased or any time the battery is disconnected. If the DTC memory has been erased or the battery is disconnected, a new readiness code must be generated.
Only erase the DTC memory if a DTC has been stored.
General Recommendations
Most monitors will complete easier and quicker using a steady-foot and smooth acceleration during the drive cycle operation, cruise, and acceleration modes.
Operating Conditions
For the EVAP monitor test, the coolant temperature and the ambient air temperature must be between 10 °C and 35 °C with a difference between them no greater than 4 °C. The ambient air temperature must not change more than 4 °C during the drive cycle procedure (e.g. when driving out of a heated workshop in the winter).
Test requirements
Erase the DTC memory Diagnostic Mode 04: Reset/delete diagnostic data . Coolant temperature must be between 80 °C - 110 °C. The Intake Air Temperature (IAT) must be between 10 °C - 35 °C. Battery voltage must be a minimum of 12.5 volts.
Fuel tank level 1/4 - 3/4 full.

Drive Cycle Procedure
Connect the scan tool. Switch the ignition on and start the vehicle.

* Idle the vehicle for 2-3 minutes.
This executes the O2S Heater, Misfire, Secondary AIR, Fuel Trim, and Purge system monitors.
* Drive the vehicle at 45-55 mph for a continuous 7 minute period, avoid stopping.
This executes the EVAP, O2S, Fuel Trim, and Misfire monitors.
* Accelerate the vehicle to an engine speed of 5000 RPM (with automatic transmission use the tip-tronic mode); lift off the throttle until the engine speed is around 1200 rpm.
This executes the fuel cut off
* Accelerate the vehicle smoothly to 60-65 mph, cruise constantly for 5 min
This executes the Catalyst; O2S, Misfire, Fuel Trim, and Purge System monitors.
* Decelerate and idle the vehicle again for 3 minutes.
This executes the Misfire, Secondary AIR, Fuel Trim, and Purge system monitors.

Check the status of the readiness code.
Note:
Depending on the scan tool used. The readiness code status may be displayed as complete, passed or OK.
If any engine monitor fails the drive cycle test. Repeat the drive cycle test until all engine monitors have successfully run through and passed.
Note:
When repeating the drive cycle operation for a failed EVAP monitor or thermostat-monitor, allow the engine to cool until the coolant temperature and the ambient air temperature are be between 10 °C - 35 °C with a difference between them no greater than 4 °C is observed and repeat the drive cycle operation.
If the drive cycle operation fails again. Check the DTC memory for stored DTCs Mode 03: Interrogating fault memory .
Repair the vehicle if necessary. Repeat the drive cycle operation until all engine monitors have successfully run through and passed. Remove the scan tool and switch the ignition off. End of operation.

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[PDX04a4]

thats a ton of shit. reminds me of a funny story, one of my former roommates was having trouble with an EVAP code and was throwing a CEL in his Benz. he kept failing his DEQ scans and couldnt get the registration passed. his initial test was in like october when it first started getting cold. well turns out Benz is like audi and the EVAP test has be run at like a minimum of ~55 degrees F, well we almost never hit that high of a temp after october in portland so he was totally boned on passing the EVAP test until this last spring. he drove around with expired tags for almost a year, finally got the EVAP part that was throwing the code replaced and passed the EVAP test. but he got several tickets, lucky for him most got tossed out once he showed he could pass the test. frustrating but funny experience.

[a4darkness]

Unfortunately, while I was following the Bentley procedure to prep my ECU for the re-test, she threw a CEL. A scan revealed:

16795 - Secondary Air Injection System: Incorrect Flow Detected

Among others, Old Guy posted the following, which was quite helpful

Upon a cold start the combi valve needs a strong vacuum source to open it and keep it open.
This source is provided by the vacuum reservoir located underneath the front left fender.
Simple manifold vacuum probably won't be sufficient to keep it open.
There should be a direct and unobstructed connection from the vacuum reservoir to the N112/N249 valves located underneath the manifold.
There should be a "T" off of this line that contains a check valve used to charge the vacuum reservoir.
Once the reservoir is charged the vacuum is held by the check valve on the "T" and the N112/N249 valves underneath the manifold.

After driving your car turn it off and let it set for a few minutes.
Trace the hard plastic line that connects the valves to the reservoir.
There is a quick disconnect in the line approximately half way between the manifold and the front fender.
It should be just behind and below the left front headlight in easy reach.
Unplug the connection. You should be able to hear the vacuum as it is being released.
If it's not holding vacuum then you have located what's causing your problem.

Several possible causes for the vacuum loss:
The check valve is defective, installed backwards.
The check valve is located directly in the line between the reservoir and the N112/N249 valves instead of in the "T".
You have a vacuum leak at one of the valve connections.

[a4darkness]

Often times this code is related to problems with the vac line connecting the combi valve and the N112 as illustrated here.

(please note, this is not my engine bay... and thanks to whomever originally made this pic)



Since I had the 3.5mm ID vac line handy, figured it was time to put it to use.

First, pull the two one time hose clamps off the sides of the pancake valve for better access to the silver combi valve below it.
(obviously, you'll need new clamps to new attach it unless you already have screw downs)




This reveals the vac line coming off the right side of the silver combi valve. Follow the line... it will run towards the driver's side and then towards the front of the car, looping underneath the manifold. Pretty easy to trace.

For some reason, likely something I did, this vac line appeared to be pinched behind the block (a few inches off the comb valve) as it traveled in between the hoses and whatnot. Weird.




After removing the vac line, use it to cut a new length of hose and map out where you want it to travel.




I re-ran the new silicone line like so, adding approx two inches to clear the mass of hoses and piping. While this line does not hold a lot of pressure, it should still be secured. Some use zip ties, but as usual I'm using the screw down clamps.



Afterward, I cleared my CEL and will run through the Bentley procedure detailed above later today.

EDIT: I should mention that I was under the impression that this vac line was too small. Not the case whatsoever. Mixed something up somewhere, my bad. 3.5mm ID worked just fine. But if there's any place where it doesn't I'll be sure to make note of it.

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[a4darkness]

Per Old Guy's suggestion, I started looking at other check valves and lines. Didn't see anything glaring but you never know.

Not too much to report here, just look dead center for the black tee-valve.



Started cutting the clamps at the ends to remove the whole section.



Before. When disassembling the hose, I looked it over with a flashlight for cracks or breaks. Didn't find anything but that doesn't mean they're perfect. But they'll due for now.



After. Unfortunately, the brass tee valve I bought from ATP was too small. Should have snapped a pic, but the OEM black T valve is about 1.5" across and at least 1" down. It was structurally sound so I kept it in there.
Keep in mind that you need to double check the direction of your check valves. Hence why I'm showing the before and after (even though it's difficult to see the flat side of the US Plastics check valves).

Oh and the black barb at the then there is a quick release that just pops out of the female side (connected to a hard line, you'll see it). However, I wanted to replace the one time clamp with a screw down to be thorough.



The screw down clamps come in really handy here. Re-installation is cake.


Cleared my code and went for a drive following the Bentley procedure. No CELs, but saw two CHPs which is odd for a rainy night around here. So back home it was. Tomorrow I'll re-verify and see how she's running.

[rollaphillie]

does anyone want me to take pictures of some things i'm replacing under the intake manifold. I have it off atm and am re doing some hoses etc. underneath. Everything is pretty much covered in this thread so im not sure if more pics of the same info would be useful but I dont mind if it'll help

[a4darkness]

Most certainly. This way we can have a better look at what's down there and more importantly accurately ID and tag pieces by name + part number.

I don't have any quality pics with my manifold removed (sans a few I've found, mostly from A4mods) so this would be an excellent addition, and perfect timing too since I'm getting around to that portion of the engine.

does anyone want me to take pictures of some things i'm replacing under the intake manifold. I have it off atm and am re doing some hoses etc. underneath. Everything is pretty much covered in this thread so im not sure if more pics of the same info would be useful but I dont mind if it'll help

[Rirruto]

A4darkness, absolutely outstanding thread. I have been wanting to tackle this stuff for some time.

I have been following the thread, and I have some feedback for issues I have run into.

In the picture in post #168, a common issue area is #2, 5, and 6. My #2 (the PCV breather tube) is plastic and I found it snapped right before it goes into the 'T" hose (#5). I got a new one, part number 06A103213F, which is metal! So no more snapping there. I'm hoping to replace it tomorrow, so I will let you know how that goes. Working in that area is not fun. Also, I have a 2003, which has the older style PCV valve (#6) in that 'T' hose. Be careful when ordering this part. I incorrectly ordered part number 035103245A from ECS, because that is all they showed. The actual valve for the early vehicles has another port coming off that valve, and the correct part number is in the pic in post #168. Completely my fault, but just wanted to make sure others don't overlook this.

For the record, 4mm vacuum hose works fine in all areas.

For the brass 'T', I actually picked one up at AdvancedAuto for about $3. Worked great! It was 1/4" and works well with 1/4" hose in that area.

I'll keep you posted on other things I find tomorrow.

[a4darkness]

Even with the recent additions, the CEL quickly returned so I was back to hunting for an answer. But, at least I'm replacing valves + clamps and inspecting hoses as I go.
Side note, while it would be nice to replace everything at once, the addition of the screw down clamps makes it ridiculously easy to swap parts in and out. Looking fwd to adding new heater hose around the engine.

Thankfully Old Guy, aarononymous and audinaut (aka javanator) have been instrumental in helping me track down this issue. Many thanks fellas.

While I'm still not ruling out an errant combi valve, progress was made last night.


I was pointed in the direction of this small hose exiting the 3-way check valve. Upon pulling on the hoses to take this picture, I heard a hissing sound. Pretty clear indicator I was on to something.
This hose is used b/c on one end is attached to a check valve which has a larger diameter than the small arm of the 3-way check valve.




Here you can see the valve 'reducer hose' removed. Wanted to call attention to the connection point below... a flexible rubber T valve of sorts.
I would speculate this piece could fail over time so if you're pulling things apart, give it a good look.




Opted to use the silicone vac line here. As the 3.5mm ID hose is fairly difficult to wedge over the check valve end, it's not going anywhere.



And installed. This is getting pretty easy.
During this swap I realized that not only was the OEM hose / coupler not holding pressure, but I'm fairly certain I had reversed the corresponding diverter valve on the original install.
It's pretty difficult to see the flat vs curved sides of the US Plastics check valves so be sure to double check before and after (taking pics of the pieces before disassembling helps).
As much as I hate to admit it, hopefully this will keep others from making the same error.




Somewhat related note, if you've chosen to do the screw down hose clamps route, I suggest you buy American.
Seriously.
Cause the batch of China stamped clamps I purchased quickly come apart under normal use. Guess they're more of a one-time-easy-removal clamp.



Cleared out my codes last night and will be going for a drive shortly in hopes of staying CEL free. Knock on some wood for a fella.

EDIT 08-13-12
As for the hose clamps, never found a place online that's both inexpensive and sells the more durable Made in USA brands till now... Amazon Supply. Just search for worm clamps and you'll find everything you need.

[a4darkness]

Really glad to hear it's of help. Kind of a bummer I'm chasing down codes right now, but that aside this is pretty fun.

I have not yet delved into that region of my engine. Making my way towards the center where all the fun stuff is soon enough. You bring up an excellent point that must be reiterated. There are slight differences year to year. Point being, verify before you buy. Good call.

I should have just gone to Advance or something for the T-Valve down there (assuming you mean underneath the manifold not replacing the rubber T-valve towards the back that I just posted about) rather than ATP's. Waste of money there.

And by all means, please add whatever you feel is relevant to the cause.

A4darkness, absolutely outstanding thread. I have been wanting to tackle this stuff for some time.

I have been following the thread, and I have some feedback for issues I have run into.

In the picture in post #168, a common issue area is #2, 5, and 6. My #2 (the PCV breather tube) is plastic and I found it snapped right before it goes into the 'T" hose (#5). I got a new one, part number 06A103213F, which is metal! So no more snapping there. I'm hoping to replace it tomorrow, so I will let you know how that goes. Working in that area is not fun. Also, I have a 2003, which has the older style PCV valve (#6) in that 'T' hose. Be careful when ordering this part. I incorrectly ordered part number 035103245A from ECS, because that is all they showed. The actual valve for the early vehicles has another port coming off that valve, and the correct part number is in the pic in post #168. Completely my fault, but just wanted to make sure others don't overlook this.

For the record, 4mm vacuum hose works fine in all areas.

For the brass 'T', I actually picked one up at AdvancedAuto for about $3. Worked great! It was 1/4" and works well with 1/4" hose in that area.

I'll keep you posted on other things I find tomorrow.

[rollaphillie]

Alright so I took some pics of the mess under the intake manifold
Once you get it off and have a look down there its not as bad as it really looks.

Im going to break it up into a few sections to try and organize it a bit. This post will be edited and more info will be added as I start taking sections apart and replacing them. If theres a specific section youd like me to try and get some pictures of or clarify let me know.

Heres a look at everything thats underneath there



Section #1- PCV System
Im sure everyones familiar with the pcv breather hose and attached pieces outlined in red here


Section #2 - N112 and N249 valves
Theres already some good pics up of this section but heres a few more with the manifold out of the way.
Im holding the n112 valve (n249 not pictured) The plate that hold the 2 valves underneath the manifold is also not pictured.


Heres a better angle of the hose attached to the two valves, the end on the left side of the picture is attached to a metal hose that goes down by the power steering reservoir


Here you can see the check valve attached to the same hose


Other end of the check valve, gets attached behind the suction pump


more to come !

[PDX04a4]

shoulda just drained your coolant instead of making a big mess.

good job, i need to get under there next summer and check things out for myself.

[a4darkness]

rollaphillie, those are awesome. Thank you.

[audballz]

Note**** Breather hoses and PCV Valves differ from MY 2002, 2003, and 2004.

From the pictures above rollaphillie has a 2004.

ETKA picture on Post #168 is of a 2003

[a4darkness]

Performed the Bentley readiness procedure a few times over and clocked some miles in various conditions and temps since yesterday's changes.

CEL has still not returned and according to Vag, she's ready. Time for emissions re-test.



Results...

100% PASS!



And in case you're interested, here's the numbers from the failure last week. Even though the failure was due to readiness, the guy at the counter commented about how my O2 levels improved from test 1 to test 2.

So, per the numbers, the fixes are making subtle improvements.



However, strangely enough I'm still showing the following code:

16825 - EVAP Emission Control Sys: Incorrect Flow
P0441 - 002 - Lower Limit Exceeded - Intermittent

So that'll be next on the list.

[a4darkness]

Did a quick search about this code and most results pointed to the N80 valve (left side, behind the airbox).

The old clamps on the left side of the N80 were pretty loose, one so much that I could pull the N80 off with a mild amount of force. So I replaced those and verified the rest. DV is correctly flowing towards the engine as well.

Nice and buttoned up.

[Rirruto]

To sum today up:
I really hate stupid one-time use hose clamps and all plastic parts on our cars.

That is all.

[a4darkness]

Troof.

To sum today up:
I really hate stupid one-time use hose clamps and all plastic parts on our cars.

That is all.

[old guy]

Did a quick search about this code and most results pointed to the N80 valve (left side, behind the airbox).

The old clamps on the left side of the N80 were pretty loose, one so much that I could pull the N80 off with a mild amount of force. So I replaced those and verified the rest. DV is correctly flowing towards the engine as well.

Nice and buttoned up.

If tightening the loose clamp doesn't help you can try removing the N80 and tapping down on the inlet side of the valve. Sometimes they will suck up debris from the charcoal canister and clog up.

[a4darkness]

Got it, thanks OG.