The only code I have is for a o2 sensor which I have had almost since I have owned the darn thing, I have been holding out to get race pipes when I can afford it. I am 99% sure I don't have a boost leak.
The new turbos have around 2K miles all of which my wife was driving the car to ensure they were broken in properly.
If I floor it from a stand still it will boost/pull totally fine, but say I am cruising along and then get on it nothing happens, my boost gauge only reads about 4psi and doesn't pull at all and if I keep it floored the CEL dings
Sounds like limp mode for sure or a blown Ypipe connector or some other big boost leak
No, I have gotten the 3 light 0 boost before & changed out the brake light switch, I wish it was that easy this time. I just ordered a boost leak tester so hopefully next week I can know for sure if that is the problem or not. I do have a CEL for a faulty o2 sensor but I have had that even before I started getting these symptoms, but I will be replacing that as well just in case
also I have Bailey diverter valves and a full silicone kit so unless one of them came loose it shouldn't be a torn hose or tbb & I have replaced the MAF, plugs & N75 valve to rule those out
If I didn't know any better I would say that your MAF scaling was off, what you are describing is usually a result of positive charge deviation. If your MAF scaling is out to lunch, while sitting at 2-3k you go WOT and the car runs wastegate pressure as the turbos spool faster than the tune(MAF scaling) expects to see. Just me 2c
If I didn't know any better I would say that your MAF scaling was off, what you are describing is usually a result of positive charge deviation. If your MAF scaling is out to lunch, while sitting at 2-3k you go WOT and the car runs wastegate pressure as the turbos spool faster than the tune(MAF scaling) expects to see. Just me 2c
sounds promising, but I have no clue what that means, could it have anything to do with my p-flo intake, I already changed the MAF?
It shouldn't have anything to do with your intake, the best and only place to start is with a boost leak test, once you are sure there are no leaks you can start to really diagnose things. You would be surprised how a couple of little leaks can affect things.
Well I was running GIAC, but my turbos & torq. converter got replaced under warranty so I swapped my stock ecu back in and left it there & I ended up just getting rid of my GIAC ecu
Can't wait to get my boost leak tester but they shipped it thru USPS so it probably won't come until next week
On the 2.7t you can unplug the MAF and still have 9psi on stock ecu.
However the code there that is causeing limp mode there is P1555 Charge Pressure: Maximum Limit Exceeded This means you overboosted at one time.!!!!!!
So your N75 valve is jacked up or blocked / leaking vacum houses in your wastegate/ N75 system. If its still controlling boost to 5 psi... most your system is still working. And it being intemitten... i would think the N75 valve or the plug in on it
2005 Audi A6 4.2L Black on Black, Bluetooth, Voice recognition, Nav, rain sensing wipers POWER SHADE (haha).... Smoked blinkers.
ok well I unplugged the MAF & started it up & my whole dash lit up like xmas. I drove it & it wanted to boost but I heard a pshhhhhhhhhhhhhhhh coming from the bottom passenger side, so it sounds like a pretty bad leak at the passenger side turbo.
I shut it down, plugged the MAF back in & now it totally over boosts, it peaks to like 19psi and tries to hold at 15psi but I got scared & just brought it home. Maybe when they installed my new turbos they didn't fasten everything down.
Have you checked the passenger side intercooler pipes? These can easily come off if not secured. Just remove the plastic splash shield and they will be obvious.
2001.5 Audi S4 6spd Imola 1999.5 Audi A4 1.8T Avant 5spd Laser
Have you checked the passenger side intercooler pipes? These can easily come off if not secured. Just remove the plastic splash shield and they will be obvious.
I checked the top one, but I gotta check the bottom one coming from the turbo cuz I noticed I can hear the turbo spinning from the pass. side so I wonder if the dealer didn't fasten the turbo outlet/intercooler tube. I put all new silicone tubes everywhere except underneath so maybe that's it
Over the weekend I put the lower intercooler silicone tubes on and I can't get to the tubes that come right off the turbos but from what I could tell they were on & fastened tight. I snooped around the n75 & all the hoses around & they seemed fine.
I got this yesterday so now I gotta get a 1" cap to block the pvc bung on the intake Y and I will be able to do a pressure test
If you have a hand vacum pump I would hook it up to the line that feeds the wastegates off the N75 valve. See if it hold vacum and make sure the arms are still connected on the turbos. You can also vag your N75 valve cycle
Im thinking if it was this big of a boost leak... your gauge wouldnt never see 19psi (which is on the other side of your throttle plate of the system) because all your boost would be going out your leak and not into your engine to show 19psi. It would be idleing all over the place and running all jacked up because all the un-metered air (both ways). Sounds to me like everything is running fine untill your wastegates are supposed to be opening. A leak in your vacum line going to your waste gates would make them not open.... or even the vacum feeding the N75 valve
2005 Audi A6 4.2L Black on Black, Bluetooth, Voice recognition, Nav, rain sensing wipers POWER SHADE (haha).... Smoked blinkers.
The dealer charged me a couple hundred dollars for "new fasteners" when they did the new turbo install, but all the clamps looked to be old so I will be giving them a call
May even want to pull up block 2 and watch the 2nd and 4th one.... thats load and MAF. The MAF is in g/s (grams per second) .... it should be pretty steady when idleing (if your still worried about a boost leak)
2005 Audi A6 4.2L Black on Black, Bluetooth, Voice recognition, Nav, rain sensing wipers POWER SHADE (haha).... Smoked blinkers.
The dealer installed the turbos about 5 months ago and this problem may have happened just after the install, but now the problem is I let my wife drive it since I was scared I wouldn't be able to take it easy while the turbos were being broken in. She drives slower than a grandma so she never experienced any problems and I drove it the other day and was like WTF is wrong with this thing so the dealer may say it's not their fault, from what I can tell they already shook me down for stuff they didn't even replace & the 1st day I got it back from them the torq. converter all the sudden went bad so I am scared to take it back to them
I'll try logging those blocks tonight, but I'll need your help deciphering them if you don't mind as I know nothing that intense
Block 2.... #4 Is the MAF .... at Idle its should be 3-6 g/s (rounds about) and 160 g/s at WFO... If your looking at < 1 and cant get but 110 and your car drops below 400-500 rpms when you let off the gas ..then pops back up.... Your looking for a leak between the MAF and the throttle plate. . if you can find one that showes the fuel trim (Block 32) and the fuel trim is working its ass off .... your looking for a big vacum leak (after throttle plate)
However.... Im thinking wastegate control issues... Other than the vacum pump.... You can suck on the N75 to wastegate lines then put your touge agaist the hose and you should fell it keeping the suction.... if not you can find your smoking buddy and have him blow smoke into that side and see where the smoke comes out.... Those little vacum lines around or rubbing the exhuast spring leaks easly
As far as block 114... if your showing 0% boost, 0% turbo load and overboosting... then duh .... wastegate control issue.
PS... did your wife make you add that one part, Because she had to give it some gas to make it goto limp from overboosting
2005 Audi A6 4.2L Black on Black, Bluetooth, Voice recognition, Nav, rain sensing wipers POWER SHADE (haha).... Smoked blinkers.
well I got the boost leak tester on today & I couldn't get it to hold pressure, it would get to 5psi & the compressor couldn't keep up. It is escaping fast from somewhere behind the motor which more than likely is the tubes coming off the n75. I tried pressure testing both of the lines coming off the n75 & neither held anything. This weekend I'll take the car more apart & check the 2 T's that those hoses go to to see if either are broken otherwise is there anyway to get to the wastegates w/o pulling the motor to see if the other ends are connected to the wastegates?
The Line you have off is your Vacum feed for the N75 (pail purple in diagram)..... the one with the blue writting (dark purple in diagram) still attached to the N75 goes to the compressor houseing..... keep sucking you may just get the turbos to turn (j/k but its not going to hold a vacum). During your pressure test you'll need to plug that hose because it goes straight into the turbo housing.
The light blue hose (light purple in diagraph) still attached to the N75 valve has a "T" in it then goes to both wastegate.... this one should be able to hold a vacum (suck on this one or use handpump)
And yes its possible to change the vacum lines without pulling the motor
Last edited by superman_006; 07-21-2010 at 07:59 AM.
2005 Audi A6 4.2L Black on Black, Bluetooth, Voice recognition, Nav, rain sensing wipers POWER SHADE (haha).... Smoked blinkers.
I sucked & blew on both that have arrows and it was like trying to suck up the last of a 7/11 slurpee, it was empty & all I got was air, I'll replace both T's just in case and hope for the best
that pic gives me a really good understanding of what goes where & what they do and will be a really big help thanks again
As far as your boost tester.... Try it again... After you PLUG the line on going to the N75 valve thats got the blue writing on it. Should hold pressure once you do that.
Your wastegate contol lines or wastegate diapham have to have a leak in them.... I am guessing that one of those lines have melted (too close to exhaust) or rubbed a hole in one (not being secure). I doupt that the new wastegate diaphrams would already have a hole in it
2005 Audi A6 4.2L Black on Black, Bluetooth, Voice recognition, Nav, rain sensing wipers POWER SHADE (haha).... Smoked blinkers.
I had a leak from a three way pipe which flaged this boost code (part number 078 133 701 AD) and found it by pressurising like you did. I then filled a spray bottle with a soap and water solution (TEPOL) and by spraying around the pipes, the leaking air caused large bubbles to form. The servo vacuum pipe from the manifold to the rubber joint on the firewall has a valve fitted mid way and the air was escaping from this. It sits in the same area but further below the plastic Y joiner for the N75 valve. No way I would have seen this without the tepol or smoke tester.
Hope this helps.
I have a 55 plate Allroad fitted with a BES engine. Oh and anyone with THIS engine who does not have the latest potted top coils, just fit a set of six as they will go at some point. I think the bad number is 06B 905 115 R and the new modified number is 06A 905 115 D. These coils are only fitted to the later engines, the early ones are the more reliable Hitachi bolt on type which are a different number.
Last edited by Flying Spanner; 07-21-2010 at 12:59 PM.
Talk about some dumb luck. This may sound silly, but if I hadn't seen it before I wouldn't have believed it myself. If you are running a boost gauge check the T-fitting or replace it. This happened to my b5 S4. The guy that bought it, about a year later, had the same prob. He spent spent two months trying to find the leak. Turned out to be a bad t-fitting to the AWE vent boost gauge. Replaced the fitting and no more issues. Believe me I was flabbergasted. Cheap and easy fix and hopefully that is all you have to do or tighten a hose clamp or replace a vacuum line and nothing major. Good Luck!
Last edited by SIKAudi; 08-18-2010 at 02:32 PM.
Reason: typo
I know this is off topic B5in but what wheels you running there
On topic: I hope you get the boost leak figured out. sucks trust me.
They are 20x8.5 front & 20x10 rear 2 piece Collectizone DDR3's that were discontinued back in the late 90's but the company went out of business for a while but they re-opened not too long ago but they don't sell that exact style anymore, the new design is a little different. They were originally chrome which was too much bling for me and the local thugs were eying them so I thought I would tone them down a little by going flat black
what they look like now:
Everyone else I am sorry I have no updates yet, I have been super busy and haven't had the time to look into it further but hopefully soon I'll be able to rip into it
For others, what should a stock ECU with stock K03s be boosting? And for the N75 wastegate duty cycle, what should it be? I vagged blocks 115 and 118 by getting into 3rd gear "at speed" and then jumping on the throttle. For the most part, my actual match the specified, but my max was roughly 8.41 psi (1580mbar - 1000 mbar (assumed, not measured))/1000mbar*14.5psi). My duty cycle was 46.3% to 50.2%. Car doesn't feel right. Feels like there is a resistance when jumping on the throttle, but the car sounds more aggressive. I replaced the air distribution pipe that had a crack at "nipple".
no unfortunately I haven't been able to work on it yet.
8psi is stock so if you are feeling resistance I would clean your MAF.
When I did my boost leak test I could hear the air escaping from behind the motor so more than likely it's gonna be one of the charge or control pressure lines to/from n75/turbos/wastegates
wow it's been a long time since I started this thread but after all the horror stories of having to drop the subframe & all that I just have been letting wifey drive it since she doesn't like boost anyways...but I have the car back so I decided to get dirty this weekend, turns out the driver's side control pressure line to the wastegate was in fact leaking, it was almost completely blown/seperated where it goes from a hard line to soft just before the wastegate.
I dropped the sway bar & lower driver's side boost pipe and I had just enough room to get in there & run my own new line, took about 2 hours to do aside from having to drill out the stripped allen bolt
I accidentally ripped out one of the connectors on the spider tube/hose contraption so I gotta wait until I get a new one to see what it feels like to boost again but I am pretty confident it is fixed
2.7T Allroad won't boost over 5psi
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Originally Posted by superman_006
on both that have arrows and it was like trying to suck up the last of a 7/11 slurpee, it was empty & all I got was air, I'll replace both T's just in case and hope for the best 
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