Stage 3 w/ 8psi = BooST problem!! Need help

[Caddy7]

I guess it is time for me to consult you guys, I have search the forum and checked for boost leaks all day...

I installed k04 and fueling myself. I also installed a boost guage. Now when driving there is no more power than stock and it boost only to 8psi. Vacume is at -20psi when idleing.

When logging block 115, the requested boost is 2350 mbar and the actual boost is 1500 mbar.

Codes are:
18320 - Pressure Sensor for Brake Boost (G294): Short to Plus, P1912
18057 - Powertrain Data Bus: Missing Message from ABS Controller, P1649
I also had a Charge pressure Negative deviation that I deleted earlier.

Now to the funny part, when leak tested today I hear bubbles inside the oilpan then under pressure. So it seams like somehow the boost leak is leaking into the oil pan . Is this possible or what can be wrong?

[Evilevo]

that bubbling is normal.

That sounds like your car is in limp mode

[gointoscott]

The vag is telling you the answer. I bet its something to do with the brake booster error code. I would start there.

[00s4slvr]

when you installed the k04's and fueling did you by any chance get a stage 3 tune??


ive seen that happened before where the person went stage 3 and forgot a tune and automatically assumed there car would be boosting 20psi and running 420whp...

[00s4slvr]

and btw how is the stage 3 on a tip? no transmission issues?

[Meddie600RR]

Check block 032...what are your LTFTs?

[Caddy7]

The vag is telling you the answer. I bet its something to do with the brake booster error code. I would start there.

Yeah, I am betting my money on this to... do you know in more detail on how to investigate this? When pressure tested with soapy water and dont see any leaks.

Can just the vacume side be tested?

[Caddy7]

and btw how is the stage 3 on a tip? no transmission issues?

No tranny problem yet!!!

(Yes I have a tune)

[Caddy7]

Check block 032...what are your LTFTs?

Please elaburate more on this...
What am I looking for on block 032 and what is LTFTs?

[audiwop]

I had an issue like this when I did my fueling and it turned out to be a Bad n75 valve. I Could not go over 8psi either.

[davism1]

Charge pressure Negative deviation is most likely your n75. Are you running a MBC in standalone?

[Caddy7]

Today I did a test drive with the N75 unplugged. There where no difference in boost so its not the N75 right? (I have no MBC)

[audiwop]

Today I did a test drive with the N75 unplugged. There where no difference in boost so its not the N75 right? (I have no MBC)

Well this might sound off the wall but I have also had a bad egt sensor cause this exact same thing as well. So if its not the N75, that might be another place to start looking...

[Caddy7]

Well this might sound off the wall but I have also had a bad egt sensor cause this exact same thing as well. So if its not the N75, that might be another place to start looking...

Can the EGT readings be logged?

[Caddy7]

I logged 032:

@idle B1S1 = 0.6%
@part B1S1 = -13.3%
@idle B2S1 = 0.4%
@part B2S1 =-14.1%

Is this good or bad, VAGCOM says +-10%

[Meddie600RR]

Anything over 20% will put you in Limp...That is what I'm dealing with right now. Your idle looks good though. Hmm.

[Caddy7]

I just looked closer on the log from when the N75 was unplugged and I actually got 100mb lower actual boost then when it was plugged in. (1520mbar vs 1430mbar)

[GetAwayFromMe]

Hook up a MBC that should tell you if the N75 is bad or not. I would almost bet it's your N75

[csre9]

It does sounds like your n75...

Buy mine:http://www.audizine.com/classifieds/...p?product=7684

[Caddy7]

Tonight I logged the EGT sensors 945degC witch is good I believe.

I then logged N75 together with the requested and actual boost and got that the Boost duty cycle of the N75 only whent up to 34% when the the ECU requested 2410mbar and only got 1520mbar.

So then I thought it might be the N75 that is not working properly so I disconnected the vacum hose that goes to the wastegate to get it fully opened.

This way I finally got boost!!! BUT, it made a terrible slurping/wirling noise like when drinking the last drops from a soda.

Now what is that? Makes me think I hooked something up wrong... got a hose backward or something and this is telling the N75 to not give the requested boost...

These are the logs
18057 - Powertrain Data Bus: Missing Message from ABS Controller
P1649 - 35-00 - -
18320 - Pressure Sensor for Brake Boost (G294): Short to Plus
P1912 - 35-00 - -
17837 - Circuit for Brake Vacuum Pump: Open Circuit
P1429 - 35-00 - -
16684 - Random/Multiple Cylinder Misfire Detected
P0300 - 35-00 - -
16687 - Cylinder 3 Misfire Detected
P0303 - 35-00 - -
16534 - Oxygen (Lambda) Sensor B2 S1: Malfunction in Circuit
P0150 - 35-10 - - - Intermittent
16690 - Cylinder 6 Misfire Detected
P0306 - 35-00 - -


I SERIOUSLY need help with this....

[obijohn22]

1st things first.. get that N75 squared away, clear the codes and go for a drive. With the boost control all screwed up, you'll never get to the bottom of anything. Get a new one or borrow a working one. Hook it up according to Bently's instruction, trace the lines to the wastegates and make sure all is well. keep this info coming.

[Caddy7]

Don't you think the N75 is working? I am thinking it is some other thing that electronicly tells it to not go higher then 34%.

The noise it made when boosting was terrible! OUCH, sounded like something that could break something.

How can I clear those brake related codes 18057, 18320 and 17837? Because as I understand it the brake is powered (or at least connected) by the turbos boost/vacum to right?

[obijohn22]

Based on what you said about your logs. the ECU requested more boost than the N75 allowed. If there was some other problem. for example a sensor malfunction or the like, the ECU would not have requested so much boost and you would probably have a code for that. Such things like charge air pressure sensor, Intake air temp sensor, etc can cause probs, but they will throw a code. Now, It seems to me that the ECU is asking for boost and the N75 is not providing enough. Now you obviously do not have a boost leak that is bad enough to prevent full boost because with the N75 disconected you made full boost. Now i am hoping someone who knows for sure whether or not the brake booster code can limit boost, But if the ECU is still asking for it in your logs than I would guess not. But i am not 100% sure about this one. Someoone on here has to be near you to allow for a swap of the N75 vavle to try. It would really help eliminate some things from the list. The noise is scary. try to take a vid and post it so we can hear it. good luck.

[obijohn22]

After looking over your codes again. It would seem to me that you have something unplugged. Trace the harness from the ABS controller and make sure that all things are ok. Being that all of the codes for the brakes are for sensors or signals, I vote a bad connection either at the ECU or the ABS controller. Maybe there is a junction somewhere in between. I do not have my manual here at work with me or i would take a look. Maybe someone can chime in with info.

[Caddy7]

Anyone know why the N75 only have a duty cycle of 34%

[GetAwayFromMe]

Who did your tune? What's the chance they forgot to tune it and you are running stock ECU?

[obijohn22]

his log said it was requesting a lot more boost than stock. so the ecu is tuned. Unless the N75 is bad i personally do not know why the duty cycle would be so low. Unless the charge air pressure sensor is bad......hmmm but that doesn't make sense either because his logs showed actuall boost being lower than requested. I still like the idea of trying a different N75 and see what happens

[Caddy7]

On saturday I'll do another leak test, replace N75 and hope for the best...

Also I would like to disconnect the ABS altogether and see if it has an effect, I have read post saying that the car would drive w/o but how would I do this?

[Caddy7]

Today I tryed with a new N75 valve and dissconected the ABS but no difference...

Checked for leaks again but there is none and I also took of the DV's, they hold vacuum and are totally airtight when shut.

The only thing I can think of now is the N249 valve that controls the DV's. When on idle there is a vacuum in those small lines going to the DV but is there a way to check if there is pressure when I go into boost?

Since I had that terrible noise when I overrided the WG, maybe that was from the DV's not having pressure to keep them shut. They would spring open if they don't get positive pressure right??

How can I check this or do I need to buy the N249 and try? There is no code for it in the ECU.

[Caddy7]

N249 was bypassed tonight....... no difference.

[GetAwayFromMe]

Do you have a MBC or can you get ahold of one? If so try to hook it up and see if you will get boost. When i got my stage 3 done i was boosting 30+psi so i had to hook one up to lower the boost.

Once you get boost if the noise comes back on again than there is something wrong for sure. It's probably what's cutting your boost down and not alowing you to boost past 8psi.

[GetAwayFromMe]

What kind of DV's do you have? Did you check the obvious? TBB, ect?

[Caddy7]

Yeah I checked TBB, 710N, N75, N249, WG lines, Soapy water leak check,

Since its a Tip I also change to an upgraded Torque converter, there is no setting neded for the highter stall speed??

[Caddy7]

Jerbel, do you have any ideas??

Anyone....

[Caddy7]

I hate when a thread don't have the solution to the problem posted so here goes:

I switched back to my stock injectors, MAF and to my APR stage 1 ECU. It now Boost 15-16psi and It seams all good. So the car has no "mechanical" problem...

Now my tuned have not returned my emails or phone calls since Sunday (3days), maybe he's on vacation this week.

[Evilevo]

Hmm, what tune is it?

[obijohn22]

I hate when a thread don't have the solution to the problem posted so here goes:

I switched back to my stock injectors, MAF and to my APR stage 1 ECU. It now Boost 15-16psi and It seams all good. So the car has no "mechanical" problem...

Now my tuned have not returned my emails or phone calls since Sunday (3days), maybe he's on vacation this week.

that is really good news that there is no mechanical prob. bad news that your tuner screwed up. thanks for the update.

Have you heard that strange noise again?

[Rated S]

I'm up in LA if you need a hand with anything. Depending on what size your injectors are (I have 60#) we could try throwing in my ECU to see if that is the problem.

Let me know if you need help though regardless.

[Caddy7]

Hmm, what tune is it?

Marc aka 10secs4

Does anyone on here have his tune on a tip?

[Evilevo]

http://www.audizine.com/forum/showthread.php?t=262946

He had problems like this with Marcs tune also. His car was running like crap, than he switched to SSP and everything was Golden ;)

It seems like his tune was also requesting a low boost for stage 3