Exhaust pulses in Airbox EGR?

Hey Everyone,

Newb here as you can tell. Always wanted a TDI and finally got one last fall (2004 Jetta Wagon w/BEW). Has been a great car but shortly after buying it I realized the turbo was probably going bad (or so i thought). It sounded pretty sweet, like a mini semi truck, really loud, but i could also hear rubbing and the occasional squeal when to much load was placed. I'm a conservative driver for the most part. I drove it as little as possible until last week when i could finally afford a rebuild. I had Ron's turbo service in Salt Lake rebuild it. He cleaned everything, repainted it, internals weren't reusable so he did new cartridge. To my knowledge everything but the housing and VNT is new. He made it look great, I read on his ebay and google reviews many people have had great reliability with his rebuilds.

ANYWAY. I installed the turbo last week. I used all new gaskets crush rings etc. I used anti-seize where appropriate and some blue (serviceable) threadlock where appropriate. I tried to make sure i did the best work I could because it is a lot of work (to me) to get that thing (the turbo) out. When I had everything hooked up i primed the turbo with oil before starting and after primed I let it run for several minutes and watched for leaks, there were none. When priming I know it had oil because i left the flare fitting on the turbo a little loose and oil shot out of it with just turning the car over, no idle.

The car ran great for 3 days until i got on the freeway one day and couldn't hold more than 70 mph. It felt like i had the A/C on with a trailer behind me. I was in a canyon and there was a grade. CEL came on, as soon as i pulled it I found 3 codes, one was "turbo charger boost control position sensor circuit low" and the other two were" turbo charger under/overboost." I can figure I'm not making boost since I have no power. I cleared the CEL and limped it home and noticed a thumping noise. After checking for exhaust leaks (none) i pulled the charged air pipe off the turbo outlet and noticed a pulse coming from it, as if one piston is leaking exhaust stroke into it. I can feel this pulse in the airbox if I just put my hand on it. I have read on TDIClub that the EGR's on these cars are somewhat tedious. I'm trying to address my pulse issue first as i feel it it worse than just not making boost. Any suggestions/diagnostics I can try? Sorry for the Novel, just trying to be thorough.

on the BEW if you replace the turbo or just the actuator you should try running the VCDS calibration procedure. apparently the ECU needs to relearn some fine-tuning. very good chance that is at least one of your problems.

that pulsating from the airbox you hear could possibly be a sign of a highly-worn camshaft.. worth taking the valve cover off to see what it looks like. there are threads on here that show pictures, but the chamfer on the cam is fairly obvious to notice with the naked eye and using your finger to feel it.

and yes, the EGR system is also prone to problems, which could also be an issue.

hopefully that "rebuilt" turbo isn't a piece of junk... the best option for a replacement to the stock turbo is a brand new garrett vnt17 - a little more $$ because you will want to get it properly ECU-tuned and delete the egr at the same time

burpod, thank you for the info. I will take a look at it tonight. Any reason why that noise would be so all of the sudden? The car ran great up until i lost boost. I have looked at the S7 from KermaTDI and the Garrett. I like em both. lots of $ unfortunately. I hope the "rebuild" is going to last for a while. He warrantee's his work for a year, but that doesn't help me if I have to take it out again because he didn't do a good job.

it is still having no power and making those noises after turning the car off/on? a typical overboost issue (such as being caused by not having run the vnt actuator calibration with VCDS) will go away after you power cycle the car, but of course happen again shortly thereafter... hopefully it's not just a crappy rebuilt turdo

yes, still makes the noises after start/stop several times. I was wondering if there is an EGR valve that redirects exhaust gases into the intake and that could be the problem? I will look into running the VCDS Calibration procedure,...still unsure about the exhaust pulses. Any chance they could be caused by the ECU not remembering how to work VNT? It worked ok for a few days, ran totally normal and built boost...

I checked the turbo to make sure it's not seized up, it is spinning at idle, sounds quiet, almost undetectable. But no spooling noise or power under any load.

well, double-check the vac and electrical lines going to the n75 + turbo. are the same codes coming back? if you posted the actual codes, it would be helpful

Code P2564 Boost Control Position Sensor, tried to send a pic, having issues. I checked connection to the VNT solenoid, it is clean and definitely plugged in. Same with the Vac line to the N75. Assuming the N75 is the small vac line that goes on the nipple near the 3 pin electrical connnector. Codes have not come back since i cleared them, which was halfway through my trip (came back as soon as issue became apparent). Probably 50 miles on the car since clearing the DTC's. A couple times the car was shut off and restarted.

Sounds like you might need a cam which is a serious issue if you let go too long. Is it making bupping noises from the intake?

turbocharged798 said:

Sounds like you might need a cam which is a serious issue if you let go too long. Is it making bupping noises from the intake?

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X2 w/intake "pulses". Seems to indicate cam/valve issues and the with the BEW this is not uncommon to have cam wear issues, from what I understand.

Bad damage on one of the camshaft lobes, but bad enough to make it cough? It's right before the eccentric. How does this happen? all the other lobes appear to be in good shape.

Pulled this out to find lots of carbon buildup, currently cleaning it.

I Know that camshaft is looking really bad, but besides pulling it and replacing, is there anything else that I should look into. I realize i should need to clean my intake and EGR. Also When pulling the camshaft, it is possible and ok to just pull the shaft without removing the head? I realize i'm asking for ways to cut corners here, but I'm short on time and money. I'm really looking to do just whatever I can (within reason) to get back on the road....any advice is appreciated.

no need to pull the head to replace the camshaft. it's basically just an extra couple steps in doing the timing belt job, which you may want to do/redo anyways if you are unsure of the quality of the current tb + misc parts.

the pic is hard to see. is there much chamfer left on the edges of the lobes? there should be a decent amount. when they are worn, sometimes there is no chamfer and you can feel the sharp edge with your fingernail.

is there much chamfer left on the edges of the lobes? there should be a decent amount. when they are worn, sometimes there is no chamfer and you can feel the sharp edge with your fingernail.

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burpod, ill check the cam today after work and try to get some better pictures. I really appreciate your advice and input. I read a thread on PD worn camshaft symptoms, from what I read, it sounds like I need to replace it. Any suggestions on a replacement cam? Any known threads or places to find detailed instructions on that procedure?

A new OEM camshaft from idparts, metalman, boraparts, etc (or other vendors associated with the forum) will be fine. A good thing to do after the replacement would be to do some serious reading on what oil has held up the best in those engines other than/instead of the VW recommend/approved oil.

i use mobil TDT or rotella T6 in mine. in my gf's golf i replaced the tb + cam at ~108k (it was pretty worn, as well as a couple bad looking lifters - although it ran just fine). she's just about at 150k now, with TDT or T6, dieselgeek bypass filter, and 12-15k change intervals. i'm going to peek at the cam in another 10k (so, ~50k of use). i used the idparts kit. one thing to consider is to get the modified cam-bearings from franko6, which i thought about getting, but was just already way over budget with car repairs/etc.

as far as instructions, google will probably find you something on here. iirc i just used the bentley instruction manual. doing the actual cam change is very straightforward, just a couple tricky bolts to access to get the tandem pump off. the annoying part is just keeping everything super clean

burpod, Just an update, you were right about the cam. After watching some videos of other PD engines with the same problem and some further camshaft inspection, that turned out to be the problem. I received my new camshaft and bearings from Frank'sTdi and installed them last week. Did the Cam break-in, runs fine and no thumps in the air box. Now I just need to figure out my turbo issue.

Thanks for you help and suggestions. I'll be running Rotella T6 since a few other TDI owners have recommended it and have used with no issues for a while now.

Another thanks to everyone for your help. Forums are the reason I can avoid the dealership. Thank's for your contributions. I have learned quite a bit in the past 3 weeks.