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Discussion Starter #1
Here's the process I did:
1. Move (cold) car from driveway to garage (it's raining). Only had it running a few moments.
2. Top off oil (a little low) and washer fluid
3. Remove lower line to the N75 solenoid in order to attach vacuum pump to
4. Adjusted VNT - lengthened rod, as it was hitting the stop at 14-15 in-mg instead of 18ish.
5. Replaced vacuum hose on N75

Doesn't seem like that would cause any problems starting? Coincidence? Did I knock something loose/broke? The glow plug light goes off after a second as normal, and the car cranks hard, but never fires. The anti-shudder valve is open and moves freely when adjusted by hand. What'd I do?!?!? Never had any problems starting before this.

Probably unrelated, but last night I hooked up VAG-COM the first time and ran through the diagnostic tests with the car running (didn't realize there was no option to select which test you want and it just does them when you click Start). But even still, I moved the car into the garage today (long after that).

Is there any functions in VAG-COM that would cause the car to refuse to start? Like immobilizer related (although I have only been into the Engine module so far)?
 

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It's not related to the N75 but that doesn't mean it was just a coincidence. Maybe you removed a plug or switched the anti shudder valve so that it's closed? (You said it's open but I assume this means at rest, make sure it's open when you start the engine).

Nothing in VCDS will cause a no-start unless you're doing a fuel pump relay test or the like.

Maybe the fuel shut off solenoid on top of the IP got bumped or pulled off?

Even if you completely disconnected all the vac lines for the EGR and turbo the engine should still start.

Did you pinch and bend a fuel line? The fuel lines run along that area. The VNT actuator also has some wires coming out of it, make sure they're not broken, it was a common problem.
 

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Discussion Starter #3
It's not related to the N75 but that doesn't mean it was just a coincidence. Maybe you removed a plug or switched the anti shudder valve so that it's closed? (You said it's open but I assume this means at rest, make sure it's open when you start the engine).

Nothing in VCDS will cause a no-start unless you're doing a fuel pump relay test or the like.

Maybe the fuel shut off solenoid on top of the IP got bumped or pulled off?

Even if you completely disconnected all the vac lines for the EGR and turbo the engine should still start.

Did you pinch and bend a fuel line? The fuel lines run along that area. The VNT actuator also has some wires coming out of it, make sure they're not broken, it was a common problem.
Gonna check the fuel shut off wire soon as I can grab a multimeter. It's possible I tapped it or something near it while checking the oil and it was at the limit of failure at the time.

Also gonna check the ASV when cranking to make sure it isn't closing once I have a helper to watch.

Fuel lines look good at a glance, and I don't think I leaned near them.

Which wires are at/near the VNT? Mine had no wires on it (I replaced it a while back) and I never felt wires in the area.

Thanks for the suggestions, I'll keep updating as I go... waiting for a multimeter and helper at the moment.
 
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2004 Golf is PD and should have the smart actuator with the plug at the bottom right? It lets the ECU know the vane position.
 

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Discussion Starter #5
Whoops, sorry that's actually a 2002 I have. Too many toys = lose track of them. Kinda like when you forget how old you are.

Anyway, figured it out. For whatever reason (and I'm concerned), I had to bleed the fuel system. It seemed like there were a few extra bubbles from normal, so I figured I'd give it a shot. I didn't expect it to do anything, but lo and behold it started! There were tons of bubbles when I put the vacuum on the line coming out of the fuel filter, and even after drawing out quite a bit there were still bubbles.
I'm real curious the cause of the air in the system though. Unless somehow I leaned on one of them near the strut tower, but even then I wouldn't expect it to let in enough air to prevent starting.
Now as it's running, I do see a near constant stream of bubbles in the middle of the clear tubing, but never really paid attention to if that is normal?
 

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Small bubbles normal. Big bubbles not normal. However, it takes a while for air to get out so drive around for a while and then see if there are lots of bubbles. Maybe your fuel return line is leaking or the IP is leaking?
 
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