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Discussion Starter · #1 ·
Hey all. I'm new to TDIs and have recently acquired a 2004 Jetta 1.9 TDI (BEW with manual transmission) which is suffering from a loss of power. All I know from the previous owner is that is was running fine, but would then suffer a sudden loss of power. On restarting the car, power would be restored for a short time before it was lost again (I'm assuming this is the car falling into 'limp mode'. The guy took it to one of his mates (a self-claimed VW expert), who attempted to fix it. Apparently he stripped down the EGR and and intake manifold to clean them, but on getting the car back it now runs even worse and suffers a constant lack of power.

I want to 'baseline' the car before I start fault finding, so first off I want to ensure that the vacuum hoses are all correctly routed (I've found one pipe disconnected and one blanked off, so all is clearly not well). I got the Vacuum Hose Routing Diagram from this forum (included below), but it would seem that the terminology used differs slightly from the descriptions used by parts suppliers when I search on the part numbers. Therefore can someone please confirm whether or not I have correctly identified the valves from the part numbers on my car?

1J0906283C - Intake Manifold Switching Valve
1J0906627B - Boost Pressure Control Valve (N75)
037906283D - EGR Cooling Switching Valve
Also, could someone help me identify the EGR Cooling Actuator? Is it Pt No 038131063E?

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before you do anything...

how many miles on it?

how long since t belt?

inspect cam?? this needs done if you say i do not know... a bad cam will blow black smoke and act as if not properly boosted.. for some reason every one wants to **** with the turbo.. when its the cam..

how is the intake?? full of sludge?? when removing the vc to look at the cam, you gotta remove the valve thats in the way.. good moment to look.. plan to use a shop-vac to suck the crap out that will come off the valve.. that little amount of crap will lock a engine up or bend a rod... where his cleaning it could also do..

as for your question.. do 1 line at a time.. that easy.. you got a pic.. :) as for which it is... when looking at the egr cooler, it has a rubber hose to it.. follow it to the switch.. be on back of manifold by cooler...
 

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I've seen that picture in TDI Wiki. So I search ElsaWin for find all TDI and TDI-CR vacuum layouts. The only Jetta's I found was
2006 Jetta 1.9 TDI-PD NARBasis 74 1K2733 BRM - 103PS BKC, BXE

2010 Jetta 2.0 TDI-CR NAR Combo 1K239L 10 CJAA - 140PS CBEA, CJAA

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Discussion Starter · #4 ·
Hey crsmp5, thanks for the advice. The car has 228K on the clock, and according to the receipts I have the cam was replaced at 164K. Interestingly the timing belt isn't listed on the invoice, but I would have thought it strange for them not to change it at the same time. That said, from another receipt I can see that the belt was replaced a 105K, so maybe they decided it wasn't worth it with 60k on the belt.

I've had a quick look at the cam, and there does look to be some wear (example below). When I get a chance, I'll get some more detailed pictures and post them on a new thread. What do you think of the wear?

As for the intake manifold, it actually seamed pretty good with just a light dusting of carbon deposits. Same for the EGR, although I did notice some evidence of a failed gasket (blackening on one side of the flange) where the EGR cooler pipe bolts to the EGR cooler.

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imo the egr pipe gasket looks like it was leaking... but those pipes do crack too.. but the way the gasket looks like it did not seal is why i say gasket

car im doing a cam in has 260 on his bad cam... no record of ever being done... but ive seen them ruin heads by 183k... i have also seen worn replacement cams too that did not last 100k... and sadly the "new" owner (i ask as to learn which cam to not buy) does not seem to know what brand was used on the worn out ones.. he has me doing his belt with 40k left on it just so the mileage restarts now..

the discoloration of that lobe is not correct imo.. id be looking really good at the lifter (could have skimped on the new ones and is deforming) to to see if its messed up and with your rubber glove on.. i feel the edge of the cam lobe (has a really defined silverness to it in that pic) to see if it grabs the glove at all like a steak knife would.. be careful it can cut like a paper cut thru the glove.. you just want to see if it tugs at the glove.. they get a nasty knife edge and if its like that.. cam is junk.. discoloration only... id say crappy cam was used as replacement.. but its worth looking really good.. to ruin the head adds bout $3k vs catching the cam before that.. about 1k.. so why its good to inspect the cam every so often

if that checks out now its time to check if the vnt adjustment is set correctly.. any thing wrong in that setting will make you chase issues so beasic settings need checked...

do you have vag-com/vcds? id also check coolent temp readings via it as the temp sensors fail and the dash gauge and the engine temps will read different values... this can lead to poopy issues as the computer thinks its running at a different temp then it actually is..

all the free stuff to diagnose things :) vs buying crap and hoping it fixes it

--------------new question------------
is it a new issue or a issue that came with the car?? i only ask as i do not know.. and a new issue vs a been there since purchased helps in diagnostics as if a "new" issue you know its not from bad cam timing or something as that should not change... but if its been a issue since before gotten.. the basic cam setting could be off... or something like that..
 

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Discussion Starter · #7 ·
So I managed to have a proper look at the cam tonight. The bad news is the cylinder 1 exhaust lobe and cylinder 3/4 inlet lobes show a reasonable amount of discolouration. I did the test with the glove and the good news is that none of the edges pulled. Furthermore the tips of all the lobes look good. From what I could see, the lifters looked ok, however I didn't take the cam off so visibility was very limited. I could see however that the silver style lifters (not black nitrate lifters) are installed. The cam is going to have to be changed fairly soon, but I don't think the damage is severe enough to cause such drastic running problems. Therefore I'm planning to ensure I've ruled out every other possibility before I sink a few hundred dollars into a car I know little of the history of (even if it means I have to tear it apart again in a couple of months).

I had a quick look at the VNT actuator, and it appears to respond correctly (and smoothly) when a vacuum is applied. Of interest, to do the test I borrowed a section of vacuum hose that ran from the air intake to the N75 valve, and guess what.....it wouldn't hold the vacuum (in fact it lost it very quickly). Therefore that's a second part of the system where I can be reasonably confident of a leak.

Next is to pressure test the remaining vacuum lines as well as the EGR cooler pipe. Once I get all the 'mechanical' tests done I'll see about trying to source a VAG-COM/VCDS. Oh, and as far as I know this is a relatively new issue, although some of the receipts show that the previous owner was chasing a misfire at 164k (led to the camshaft replacement).
 

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good catch on the silver lifters :) but do not remove the cam.. there is 100+$ in bolts that you have to replace... you now know ow to inspect it.. so every 10k id look for issues.. as you know of silber vs black lifters..could be from the odd wear on cam or cheap lifters..

yup that hose leaking will be bad.. but the nt valves leak air to vent it in design.. so you wanna test from the nt side of the lines... also the fresh air portion of the line from air filter box... its gotta flow air unobstructed.. spider eggs, pinched hose so on will cause flow issues to the nt valves which then cause egr/boost issues
 

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Discussion Starter · #9 ·
So I have an update. I spent some time tracing the vacuum hose routing in the car, and comparing it to the VW Vacuum Hose Routing Diagram. In my first post I mentioned a 'stray' hose that was disconnected, and as it turns out the hose is not on the diagram. On closer inspection, it originates from a T-Piece in the N75 to VNT Actuator Line. The connector looks like it's designed to also serve as a one-way valve (to close the open line), however when testing the line between the N75 and VNT Actuator it will not hold a vacuum; it's leaking from this connector. Therefore no vacuum = no turbo.
 

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