vandermic07
Veteran Member
Is the intake coked up after the EGR? It might not be getting enough air.
Your post on the throttle position and IP correlating. How do I do that?Is the intake coked up after the EGR? It might not be getting enough air.
I'm ignoring the possibility of the intake being plugged beyond the EGR because you said that was cleaned -- and I've seen intakes with BIC pen size holes in the sludge and the cars could still make boost, surprisingly enough.Note: The strangest thing is happening. After revving the car up, I can hear a thunking noise from inside the EGR/ASV. If I pull the vacuum line to the unit, the sound stops. The engine pulses slightly with that sound as well and doesn't run as well at idle. I did recently change out the EGR/ASV with a Chinesium unit as it was blowing oil out of the weep hole around the time that all of this happened.
It goes all the way to the stop. I will review again, but as you mentioned let's see if that passes.If the actuator moves then there is vacuum. Does it go all the way to the stop or only move slightly? It should go all the way to the stop screw. You should also see the charge air pressure change on that screen. If it does then the N75 is working and so is the actuator. Let's assume that passes.
Question: You said you replaced the EGR valve? Where'd you get it? Unplug the vacuum hose to it and stick a golf tee in the hose (plug it.) That should throw a code rather quickly (the ECU, when it cycles that, expects the MAF to drop and if it doesn't it trips a code) but eliminate a stuck-open EGR solenoid that is slamming the valve open (which can drown the intake with exhaust that has no oxygen in it.) No fire, no pressure, doesn't matter where the vanes are you get no power.
I'm ignoring the possibility of the intake being plugged beyond the EGR because you said that was cleaned -- and I've seen intakes with BIC pen size holes in the sludge and the cars could still make boost, surprisingly enough.
If you completely run out of other possibilities the cat may have collapsed internally and is blocking exhaust flow. But I hate going there without running out of other possibilities first since if you're wrong on that one you just bought something that isn't broken.
It's alright. I might not have mentioned it. Thread is getting long, lol.Sorry, I didn't remember you saying that the intake was clean.
I never thought about the CAT. Definitely worth a try.
As for Throttle position test, I know you can check throttle position in VDCS but I'm not sure if it monitors the IP position as well. I was hoping someone else would chime in to see if there is a possibility there.
Yeah, I resisted doing the blockoff since this is an auto.When was the EGR valve replaced? Before or after the car lost power? I hate CRAP (Chinese replacement auto parts) with a white-hot passion -- and with good cause. Got a block-off plate (and a new EGR gasket afterward) handy?
Vander, I don't think that's it although its POSSIBLE the IP is boogered. I say "unlikely" because the fault precedes the replacement, it did not occur when the replacement was made.
It now appears we know:
1. The actuator works.
2. The N75 works; when cycled in Basic Settings it runs the full range. (What's the boost, actual do when it cycles?)
3. There remains insufficient oxygen or insufficient fuel, ergo, no power -- but the fault occurred before the IP was replaced, which tends to implicate oxygen, not fuel.
What you got left, reasonably, is that the intake is being polluted with exhaust (EGR wide open irrespective of drive to the valve) which means there is no pressure to spin the wheel and make boost (no matter where the vanes are) or the exhaust is plugged and thus what IS there can't get out, scavenging is for crap and again you make no power.
In either case the ECU will not inject fuel it doesn't believe it can burn (from the MAP sensor.)
The 10mm pump is quite capable of driving enough fuel to get to redline. Even with smaller than auto injectors. IFF the pump is good, the change shifted the timing significantly. NA tdi's whilst slow are not having issues getting to redline unloaded.Pak, he has a 10mm pump with auto nozzles; that thing is a lawn mower without boost, and by his data he has no boost despite the ECU asking for boost.
My money at this point, given the above diags (known good vacuum at the input to the N75 and actuator works when vacuum is applied to the hose at the N75 heading to it) my bet is that the N75 is not working, either electrically or it is mechanically jammed/plugged closed.
There may be other problems too but eliminate that which you can without spending money first.
CongratulationsI pulled the down pipe and revved right to redline!!!
Thanks for and everyone else for your perseverance. It is an aftermarket exhaust put on by the guy who sold it to me. We still talk to this say. He got it from Rockauto but was some cheapie to get him by inspection. The cat is not flanged so rodding it might be a bit harder. Off road pipe would save money but wouldn't make sense as a pass on to my kid.Yep - collapsed and packed cat.
Not that hard to R&R; the replacements are from the flange (so including the flex) to behind the cat. The part (third-party) is about $300. Plenty of people have cut it out and straight-piped it but I recommend against that. You could also go the "ghetto" route, remove it and rod it, basically breaking it up and dumping it out. It then LOOKS like it has a cat but doesn't. Recommend against that too. Both make for a fairly loud car too, even with the muffler and obviously if you get tailpipe sniffed on an inspection you fail.
....I know you were tossing and turning. Thanks so much for your help!Oh dang! Glad you figured it out!!
This was a thought that I had in the back of my mind!!The only question I keep coming up with is, 'why is the original plugged?' Just not liking the idea of replacing and then having it come to grief too...but that is perhaps for another post.
cheers,
Douglas
So is Michigan...D-Oh! So I shop for these in the south.My '04 from Florida, son's from Atlanta and the '02 from North Carolina. Michigan cars are perhaps good for engine donation...Upstate NY and northern PA are brutal on cars. Rust, rust rust.
That is the way that I drive. Makes sense. Not sure about my friend who was the previous owner but I would imagine pretty much the same.Years ago I bought an A3 Jetta TDI with 34K on it, and the cat was plugged. When the elderly owner took me for a test drive it made sense: he never got the engine over 1500 RPM.
Right, so many bases were covered in this one thread. I got pretty dirty on systems that I was afraid of before. This is great.God, I love a happy ending. I can see by gazing into my crystal ball that a lot of fueling and boosting issues in the future are going to get fixed from the knowledge shared in this thread.