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2005 Passat GLS, Auto, 1.8t, AWM engine, 152k miles.

:thumbup: First off... a really big thumbs up to all the VW owners who take the time to document with words and pictures what they have done to resolve issues. I have spent countless hours reading through the posts from this forum and following links to other posts or documents. I had best intentions to document my travails of rebuilding my 1.8t after a Timing Belt break, but I just didn't take enough pictures or document well along the way.

And forgive me, but I did an injustice to my car. About a year ago I knew the timing belt was approaching 90k, AND I was in the middle of replacing the Auxiliary (A/C?) fan, but I was in a hurry to get car running and decided to wait on the timing belt... Don't do this. Not two weeks later, with just under 90k on timing belt, it gave out at about 70 MPH. Of course... bent valves and slightly nicked pistons. I then furthered the injustice to my car by letting her sit for a year before fixing her. With 4 kids in school I just couldn't bring myself to pay to have done, or make the time myself.
Well, two months ago I dove in.... I read a ton and bought a Bentley manual like was suggested my many - and started tearing into the car. The wife lost all hope of seeing me in the evenings (after 20+ years I'm not sure that was the main concern for her) and I think she doubted my resolve to complete the project, or ever see the car running again. A Passat torn apart with no front bumper and the block seemingly hanging out of the front is quite a site... especially with 4000 vacuum hoses hanging around. I have learned a lot, and probably have already forgotten some of what I learned. That is why I especially thank the mechanically inclined who find such joy in cars, and VW's in particular, that take great pains to learn best practices and then share them. Kudos to you. Gratuitous Bowdown... :bowdown:

I will post some rough pictures of different parts... but I will not try to list everything in order. I have dealt with many of the topics of discussion during this project... replace or repair the Timing Chain Tensioner?, How to replace the timing belt, Is the Tool Kit for timing necessary (Wish I had it...darn hard to adjust that timing tensioner with needle nose pliers) what gasket sealant material to apply to the Valve cover gasket and how much, use of anti-seize grease in some places, and Lock-tite in other places, degunking the engine, and of course, the dreaded Low Oil pressure (I did learn something here: GET an OIL PRESSURE GAUGE. This will give you immediate and precise information about what is going on with the Oil pressure).

When I restarted the car the first time after replacing all the parts, I was ecstatic to see she started right up, even with old gas (should have drained it... I know), and with no engine codes at all! Right? I know.. I couldn't believe it. Ran a little rough in gear, but then straightened out after I added some octane boost. But then the STOP engine light with the low oil pressure warning. But she sounded great. I stopped and restarted and she ran fine for a while. But happened again. Went to Harbor Freight and bought an Oil pressure gauge... installed just above the Oil filter in spare plugged hole like I read on a post. Worked great... just routed hose through driver window for now. This is a large shop gauge. I could see that the oil pressure was fine until the engine got really warm... not just warm but really warm... at 190 degrees for a while. Then, upon deceleration, the pressure would dip just under 20 psi, and light would go off. I noticed that if I then gave it some gas in neutral, say 1500 rpm, the pressure would go up a few psi, say 22-25 PSI, low but at least I knew it was getting some oil. I ALSO NOTICED, that if I turned it off, waited just a few seconds, then restarted, the pressure would be much better. From what I have read, I think this is due to the Oil Sump screen being partially clogged plus a somewhat worn pump gear, and when the oil got very hot and thin, the worn pump couldn't compress the thin oil as much, plus with the screen somewhat clogged, it would not create good pressure. Instead of immediately dropping the pan (which I should have done while replacing the head and all the timing belt, etc.) I decided to go the route of first trying an engine cleaner. (Back up here: Note: I had ran Diesel all through the block when I had the head off, letting it run down the oil return ports in the block down into the pan. I used a cheap fluid hand pump from AutoZone and placed a large plastic storage container under the oil drain hole. At first I just pumped the diesel into the top of the block and let it sit in the pan. Then I drained the pan and just kept running it through as best I could. I also inserted the outlet hose from the pump into the oil drain hole and pumped the diesel so it could wash around inside the pan some. Then let it sit in the pan over night. I thought this was enough, but yet I was still having the Oil pressure problem.) After the re-assembly I used basic oil and a cheap filter to just clean out the system, then put the synthetic in with a clean VW approved Mann Oil filter. A small improvement, but still low pressure. I then added some seafoam to the oil (Parts store didn't have AutoRX), one ounce per quart, and ran for a while. The Oil pressure is better now. I will get exact numbers, but now even when hot, the pressure is above 35 PSI under a load... say driving at 3k rpm. Much better than it was. I imagine I still need to clean the screen and probably rebuild/replace the Oil Pump. But that will need to wait until my older son returns from college and can help me... after all, I am doing this for him.

Okay, a lot of background but this is where I am today. The car is running so smooth I am thrilled, however it is low on power. I can hear the throttle open with the gutteral low throatty roar of an open intake, but just not much power. The engine throws a P0299 code... low boost. I know that I messed up the plastic connector going into air box, but it still seems to make a good connection. I could really use some best practice advice here. I don't want to just start replacing parts. I read that it could be the Diverter Valve, or the boost control solenoid (06A906283E N75). Or possibly a very large vacuum leak, but I don't hear anything and cant find it. I bought a vacuum boost gauge - idles around -20 boost. When driving under full acceleration the vacuum will rise to just about zero, but not get positive boost at all... I can hear the turbo spooling up... at least I think I can.
I hear that there is some VAG COMM? software that can tell you much more than the code from the Auto Store... but I just don't want to give it and take to the dealership, nor can I afford to. Is there some other way I could get a diagnosis, or better info out of the car? I'm losing steam now but I am so close. I really want to have this running well for when my son returns home at Thanksgiving. Would really appreciate some advice.
If there is anyone in the San Antonio or Austin, Texas area that has the software, I will try to get the car to where ever they are are if they could possibly assist Will buy them a nice dinner???
Anyway, for now, just appreciate some advice, or even just some encouragement to keep going. Thanks, Lance
 

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If there is anyone in the San Antonio or Austin, Texas area that has the software, I will try to get the car to where ever they are are if they could possibly assist Will buy them a nice dinner???
Just buy one of the blue cables off the eBay or Amazon for $10 and free download the Lite version of VCDS software. That's all you need to scan your car.
 

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Sorry I am late responding... I am on the northside of New Braunfels...about 30 minutes from south Austin. I imagine my car could make it to south Austin.
 

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What are you looking to use it for? Just read codes? It can't do much else.
 

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What are you looking to use it for? Just read codes? It can't do much else.
Maybe I was expecting too much... I thought it would be able to indicate if the N75 valve was being triggered to close the wastegate (not sure if this is the right logic). I really wasn't sure what all the software could provide. I basically was hoping to get a good idea of where to go next. I think I will start by taking the front back off the car, double check the connections to the airbox and the N75.
I was hoping that the software could give me an indication if it is a problem with the sensor in the airbox or the N75 boost controller(?). I suppose I should also check the Diverter valve. Perhaps all the boost is going.... where?
 

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.Okay, a lot of background but this is where I am today.
Yep, that story was too long for my short attention span! Anyway, it seems that your problem is no boost. That points to something wrong at the turbo, and VAG-COM may not be of any help if it is a mechanical problem. First, I'd remove the rubber duct at the snout of the turbo's compressor, and then use your finger and thumb to rotate the impeller. It should turn absolutely smoothly, almost no friction, and not bind or rub the compressor housing if you gently try to wiggle it up and down or side to side. If that's OK, then the next thing is the waste gate, which if burned out will bypass too much exhaust to allow boost. The problem here is getting a look at it, because the cat has to be unbolted from the turbine housing (one bolt is difficult, access from below with a LONG extension) and the exhaust pipe uncoupled under the car. If indeed the wastegate is done for, then you have to remove the turbo to either replace it, or try fixing the wastegate. That's what I did, using stainless steel washers and a stainless steel screw and nut in place of the original riveted-on wastegate disk. I also squashed the screw threads so it couldn't come undone and ruin the cat
 

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Discussion Starter #9 (Edited)
Yep, that story was too long for my short attention span! Anyway, it seems that your problem is no boost. That points to something wrong at the turbo, and VAG-COM may not be of any help if it is a mechanical problem. First, I'd remove the rubber duct at the snout of the turbo's compressor, and then use your finger and thumb to rotate the impeller. It should turn absolutely smoothly, almost no friction, and not bind or rub the compressor housing if you gently try to wiggle it up and down or side to side. If that's OK, then the next thing is the waste gate, which if burned out will bypass too much exhaust to allow boost. The problem here is getting a look at it, because the cat has to be unbolted from the turbine housing (one bolt is difficult, access from below with a LONG extension) and the exhaust pipe uncoupled under the car. If indeed the wastegate is done for, then you have to remove the turbo to either replace it, or try fixing the wastegate. That's what I did, using stainless steel washers and a stainless steel screw and nut in place of the original riveted-on wastegate disk. I also squashed the screw threads so it couldn't come undone and ruin the cat
:) Thanks for the suggestion. Not sure it helps, but during the rebuild, I did make sure the wastegate worked okay... I actually repaired a small chipped area on the wastegate seat (where the wastegate rests against the housing to make a seal). It was chipped and I repaired it. Also, even with the wastegate seat not sealing well, the car was running much better than this prior to the Timing belt break. And while I had the car apart, I cleaned and checked the turbine. It had some play, but would turn easily by hand and when I used compressed air to spool up the turbine exhaust side, the intake side would put out good pressure; the turbine seemed to spool up pretty quickly. I pre-oiled the turbo before reinstalling, and thoroughly cleaned the oil feed line by soaking in diesel, then hooking a pump to the line and running diesel through it for several minutes. So I think the turbo is working and the oil feel line is clear.
I would like to ask if you know if the wastegate is normally closed... for some reason I don't remember... does the solenoid have to force it closed... or force it open? If normally closed, could I disconnect the vacuum tube to the solenoid and see if I get pressure then?

Oh, and good job on your repair of the wastegate! I thought about trying to remove the wastegate arm that holds the disk (welded rivet?) but couldn't see how to do that.
 

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You can also buy a cheap manual boost controller (cranked down to low boost for safety) and take the N75 out of the equation to test (keep the electrical plugged in). Keep a light foot because boost (if working properly) will come on fast with only light throttle.
 

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:) Thanks for the suggestion. Not sure it helps, but during the rebuild, I did make sure the wastegate worked okay... I actually repaired a small chipped area on the wastegate seat (where the wastegate rests against the housing to make a seal). It was chipped and I repaired it.
So you've already got that covered -good. Take a look at the rubber hoses on the pressure side of the induction system. A split somewhere, even if pretty small, can dump plenty of pressurized air.
 

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Unrelated but isn't the proper term for a vag doctor an OB/GYN? Sorry, I couldn't resist.
Go sit down. In the corner, over there. :roadblock: :poke:
 

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You can also buy a cheap manual boost controller (cranked down to low boost for safety) and take the N75 out of the equation to test (keep the electrical plugged in). Keep a light foot because boost (if working properly) will come on fast with only light throttle.
This is what I'd recommend. You'll know the turbo is functional within ~1/2 second after reaching ~2,200 rpm...about a half block. You'll need to keep the revs below ~2,000 rpm (until you get the N75 reconnected) if you sense boost. It's like a night and day test - not at all subtle. ;)
 

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Okay, after reading what you guys have suggested, and reading some other posts, it appears that the wastegate should normally be in a closed position. Therefore, I'm assuming that it should be in a position to allow the turbo to create boost unless the N75 valve sends pressure to the actuator that opens the wastegate. I now see why you are thinking that either the turbo is bad or there is a serious leak on the pressure side. Absent some strange signal to the N75, or malfunction of the N75 valve, or a blown Diverter valve, there should be some positive pressure if the turbo is funtioning... Is this correct? I just really like to fully understand the big picture when trouble-shooting a problem. Thanks.
 

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If the turbo is in good mechanical condition and the DV and wastegate are not defective (or commanded to release pressure) you need to have boost. I think this is what you are asking, right?
Simply put, you either have a mechanical problem (is the turbo making any noises?) or a control problem. My guess is a vacuum leak (N75 would be the first one to replace). I use some vise-grips to "choke" the vacuum lines going to the DV or wastegate, but I do it only for a short time to check (with VCDS) if it makes boost. The boost will go VERY HIGH without the wastegate control!
You can buy a bluetooth OBD2 adapter to use with your phone and watch intake boost/vacuum.
 

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November 10 - Update. Okay, I found the cause of the turbo leak... and it wasn't small. The large hose from the bottom of the intercooler to the cross pipe was off... I know... how did I miss this? :-(
I actually don't remember removing it. It is kind of hidden and unless you look closely it appears to be inserted. I used a large clamp to try to secure it. AND I have some boost! Yes!. But a few minutes of spirited driving and POP... whoooshhhh. It kept popping off. Then I realized the housing of the intercooler is hard plastic and the clamp wasn't going to help... (darn my old eyes) and that it needed a retaining clip. I found the clip on the workbench. (had removed it months ago... long project). Now it stays on. The difference between no boost and 5-6 pounds of boost is amazing.
Now, most of you would say that 5 lbs of boost is so low... but it does feel nice right now. The engine with the rebuilt head is so nice... I thank the Lord for helping me get this running... and PassatWorld of course.
I would like to ask... I am getting about 6 PSI max boost. Remember, this was with a chipped wastegate seat that I patched. I think it is doing some good because it is running better than before the timing belt break (but also with a quality Head/Valve job - will provide link to the Cylinder Head rebuild guy in Austin, Texas below). I have read conflicting Boost numbers for a stock engine. I have read 8-9 PSI, but elsewhere have read that people generally only get around 6 PSI with stock setup. Can someone point me to a definitive source, or knowledge from years of doing this.

Or, if you have personal first hand knowledge of standard boost pressures from YOUR car, would like to hear that... but I'm only interested in hearing numbers from people that have a vacuum/boost gauge on a fairly stock setup. No second hand stories of your cousin getting 12 PSI when he installed $200 Diverter/Blow off valve from Snake Oil Car parts... Just not gonna listen to that stuff. It's misleading and causes people to go out and buy a Diverter Valve for their stock setup thinking that is going to improve performance.



*Cylinder Head Rebuild. Brooks Elliott Cylinder Heads This guy is the real deal. He is the owner/machinist. Cool hidden shop in Austin, Texas with serious nice equipment. Not my cousin or even a friend... Just met him looking for someone to do this job. Even the graphic in the background of his Web page is a 1.8t head. He knows these heads Watch the video... he has a high end CNC machine that he programs to cut and angle the valve seat. Not cheap but not expensive either. I paid $720 for the machining and valves. He replaced 7 exhaust and 4 intake that were bent. Note: I did remove the Timing Chain Tensioner, Cams, and Hydralic lifters to help same labor.... probably saved a Hundred bucks by taking him just the Head with only the valves.
 

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So now you have a nice running car and boost and you want more? Jeesh!!

Reminds me of the joke about the Jewish Grandmother that takes her grandson to the beach. A huge wave comes and washes little Joey away, gone, done. Grandma is hysterical and pleads with God to return little Joey, anything!! Please God...tears running down her face...another big wave comes and spits Joey out on the sand. He's fine. Grandma scoops him up, looks him over and says " He had a hat"
 

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Stock AWM (my experience with 2004 model, tip trans) puts out 11psi max as indicated on a VDO boost gauge.
 

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Ha ha, truth to that story about human nature!

2005Passat, glad that you figured it out. I thought an air leak would be the reason after you checked the other things.
 
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