01 a4 b5 quattro 1.8t upgraded to k04-015x rs6 char wierd boost fluctuation problem

[Rkring5250]

Hi guys hopefully someone can shed some light on my problem iv tried almost everything i can think of to fix the issue and iv done alot of shearching on here and cant really find anything on the issue im having with my 01 a4 quattro b5 1.8t awm with a k04-015x with rs6 char upgrade. Also have other mods car ran great for the first half hour after swapping turbos then i got on it a little bit pulling out of a gas station and boost jumped to 30 psi ever sense then anytime im at partial throttle my boost like pulse it builds then drops to zero then build and drops to zero repeatedly. Iv even tried bypassing the n75 and running just the mbc still same story.. if u hold wot it wont go past 10psi but if u let the pedal up kust a tiny bit it will go up to 17 like its supposed to then drop to zero and build again. If any one can help at all id appreciate it im about stumpped here. If u need further info just ask and ill gladly supply it. Thanx

[Bordom]

Sounds like boost leak. Check all your hoses

Everything graciously mispelled by Android

[Rkring5250]

Yea i was curiose of that myself i am going to run a boost leak test hopefully today or tom. I guess i should have mentioned i literally put the new turbo in a few days after buying the car bc the wastegate on the k03s was gone. But the whole n75 valve set up is new to me im used to my previouse dsm set up. But everything i pull up on the n75 valve makes it sound as though the previiuse owner mighy have it in wrong but i cant find a pic. Of how it looks installed stock on this car to make sure mines in there correct

[Davdraco1]

Is the car tuned for this turbo? What diverter valve are you using?

[Rkring5250]

No its not but iv done extensive research that says it will run fine just wont get the full potential out of it unless i get it tuned for it and if im beating on it it will run a little lean.. but like i said it ran perfect for a while at first after the swap then on a pull out it jumped to like 30psi and has been fluctuating like crazy ever sense.. and i have a dual port bov wich ran perfect on my k03s bc the 01s have that learn feature or w.e where they run rich for the first day or too then the computer corrects it.. but i also have a brand new forge 008 wich i also installed and tried still same result.. there only two things left i can think of ones the n75 is installed wrong and the other is mayb a bad wastegate actuator or lose adjustment nut. Do u have any idea exactly how the n75 should b installed on a 01 a4 b5 1.8t awm? Right now its set up as to where if u was holding it to look like a perfect T and the top right port of the T was the long port.... the long port is going to compressor housing nipple the short striaght up and down part of the T goes into the intake piping and the left short part of the T is going to the wastegate is that correct or is that wrong bc i can not find a good pic of how the stock n75 should b installed correctly.. once again thank u got any insight. I am mechanically inclined but this n75 set up is a whole new ball game to me

[tar]

Google b5 n75, hit images. Ur mega paragraph mindfucked me so I'm not gonna reread to see what you were asking lol

https://www.google.com/search?q=b5+n...7Qq3tDHpr0M%3A

[B5nDisciple]

This should help too...found it on Google.



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[Davdraco1]

If your car isn't tuned and you hit 30psi then your ecu prolly thru it into limp mode bc it saw triple the boost level it should have. I would email Ian at reflect tuning (kompresd) and ask him about it. He'll prolly say you need a tune. And I've never heard about the "learning feature" when using a BOV on an 01. I could be ignorant and not know about it but everything I've ever read say keep a DV in there and never put in BOV.

[Rkring5250]

Hahaha my bad bud just tring to b theral bc this shot gots me so irratated. But if thats correct and the long end goes into the intake then mines ass backwards for sure. Wonder y it didnt mess with the k03s that was in before my new turbo. Then again the wastegate on the k03s was completly fucked and didnt build boost till almost 5000

[Rkring5250]

Yea iv read lots of stuff that says that too but iv also read lots that says the 01 awms are the only ones u can run like that that will adjust but thats just what i read it seems to b fine though with the last turbo. Im a trt flipping ny n75 around tom and ill post a update

- - - Updated - - -

Ill try emailing hkm also bc i do need and want a tune asap

[tar]

Yea iv read lots of stuff that says that too but iv also read lots that says the 01 awms are the only ones u can run like that that will adjust but thats just what i read it seems to b fine though with the last turbo. Im a trt flipping ny n75 around tom and ill post a update

- - - Updated - - -

Ill try emailing hkm also bc i do need and want a tune asap

Whose khm

[Davdraco1]

Yea iv read lots of stuff that says that too but iv also read lots that says the 01 awms are the only ones u can run like that that will adjust but thats just what i read it seems to b fine though with the last turbo. Im a trt flipping ny n75 around tom and ill post a update

- - - Updated - - -

Ill try emailing hkm also bc i do need and want a tune asap

He will probably say you'll want injectors, fmic, full exhaust. Possibly FPR and different MAF housing. Or he will write a tune just to get the car running properly. And sorry if you already have those mods, I'm halfway thru my first cup of coffee and can't remember.

[Rkring5250]

Well i switched the n75 around to the exact same as this pic and its still doing the same thing.. i kinda figured it would sense i already tried bypassing the n75 and running straight on a mbc and still same result..thats is y im so stumped. I no i need a tune but like i said before it did run fine with this set up for a little bit.. only other idea i have is mayb the wastegate adjustment nut is lose or the actuator diaphram is ripped would that cause this?

[Davdraco1]

Put compressed air to the wastegate line and listen to see if it opens and closes when you take the air away. If it opens and closes then your WG is fine.

[SynapticA4TQM]

Something went wrong for it have been able to boost to 30psi. Since you don't have a tune, I'd put it back to stock as much as possible.

If you don't have a tune, then it's NOT supposed to go to 17psi.

What manual boost controller do you have? If you're still running the n75 and the MBC, the n75 is probably trying to keep you in limp mode (5psi of boost) while the MBC is screwing with things.

It sounds to me like you're trying to push more boost than a stock tune is supposed to, and then are reading different complaints about the brand of turbo you have and confusing yourself about the whole situation.

If you think it's a bad actuator, take the turbo off and make sure the preload is set correctly... Raise the top nut up a few threads, raise the lower nut up against the wastegate arm until finger tight. Mark the nut and the wastegate arm piece, now with a 10mm wrench, tighten the lower nut three turns. Some
Might say do it more, but that's the right way to do it. Make sure you lower the top nut down onto the wastegate arm piece. Also make sure you put the retaining clip back on.

If you think the wastegate actuator is bad, attach a source of controllable compressed air to the wastegate line. Start at 0psi and very slowly increase the psi of air. This will identify the crack pressure of your wastegate. It should be between 6-8psi.

If you think the wastegate arm may be faulty, see if you can move the wastegate arm in and out from the turbine housing. This would be a failure of the wastegate bushing.

If all that checks out then your wastegate is fine. Next step would be to consider how you have the MBC plumbed. If it is in parallel with the n75(to prevent spikes) your MBC may be sticking and the n75 is catching hell bc of it, if the MBC is inline with the n75, I'd definitely suspect a faulty MBC.

If you don't have a tune though, you're pushing it to operate WAY outside the normal range of boost. You're right, a ko4 can be used with no problem with a stock tune. However, this isn't the case here. It's still not necessarily catastrophic, but the ecu is definitely going to be fighting you on the boost your trying to make.

Last thing, if you have vagcom, check your codes, clear them... If be willing to bet that for the next few minutes the car would run like you expect it to... After that, back to what it's doing now.


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[Rkring5250]

Thank u for the in depth instryctions on the wastgate trouble shooting. Im going to try that on my next day off here. I guess i did forget to mention i have two diffrent ecus the one in it now is chipped from mtm set at 17psi and i also have a stock ecu wich i am considering throwing in just to make sure its nothing with the ecu.

[Rkring5250]

The only codes it is throwing is secondary 02 bank 1 from my cat delete and secondary air injection pump

[Rkring5250]

Ill c if i can somehow post a video of what its doing its almost as if it has a heart beat lol

[Aragorn]

The ECU will be doing all sorts of interventions if you've fitted an RS6-K04 hybrid to your car and are trying to run it on a stock tune. It will run, yes, in so far as you can drive it around, but the ECU requires tuned for the significantly larger turbo, and you'll almost certainly need larger injectors and a MAF upgrade.

Disconnect the N75 electrically and leave it piped up as normal and see what happens. If you then get a sensible 5psi, its almost certainly a tune issue.

[Rkring5250]

Well i bypassed the n75 and just ran a vacume line straight from the compressor housing to the wastgate and it held steady at 7lbs and was smooth as butter so atleast i no the tirbos ok and like i said i have a mtm ecu tuned for q7psi but i think i am just going to keep the n8t bypassed and run it from compressor housing to wastegate until i can get my ecu shipped or find someone with a ecus for sale that will work.. i have a bigger maf for it just cant put it in until i get a ecu that car run it and want to order injectors and a fpr asap so if any of u guys can send me in the right direction for a ecu tuned for what i already have done and tuned for a bigger maf, injectors, and fpr.. and a set of like 60lbs injectors, and a decent fpr.. i no im im hard to follow with my paragraphs so of anyone could send me in the right direction for a fairly priced ecu set for my mods plus injectors, fpr, and bigger maf. And a set of injectors ajd a fpr please it would b greatly apreciated thank u

[Rkring5250]

And thanx again to everyone for there input and advice its greatly apreciated im mechanically inclined but ill b the first to admit when i dont no something and these audi/vag set ups are still new to me yet