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cleanandsimple
04-01-2007, 07:09 AM
I can't figure out why my Giac chipped car will not boost past 4 psi. If I pull the vacum line on my wastegate it will boost 15-20. I know a vw/audi speciality shop and he sold me a used wastegate for $20. That didn't work and I also tried a different n75, checked for boost leaks, and vag-com. Should I try a mbc to bypass a n75 or is there a reason why it will boost like crazy with the vacum off and not with it on. Did I get another bad wastegate? Can you pull the vacum off and still boost past 5 if you are in limp mode? Any help would be awesome. I'm getting so frustrated with this ongoing problem.

Ewok_Fetus
04-01-2007, 07:12 AM
What did VAGCOM say when you scanned?

pipe7284
04-01-2007, 07:18 AM
i am in the same position as you. every time i scan it i get a code, replace the parts and then another CEL and replace more parts. a cannot manage to get it past 4 psi (limp mode). now i have to buy another O2 sensor.

quattro16
04-01-2007, 07:37 AM
Well first the wastegate dosent use vacuum to open. It uses actually boost pressure coming from the n75 to open. So hook up a handheld pump and see
if the new wastgate opens, you can use a mirror and look down behind the turbo. And whats the faults you throwing?

AudiRacerS4
04-01-2007, 07:42 AM
if you remove the line from the wastegate you should be making more than 15psi of boost

cleanandsimple
04-01-2007, 08:27 AM
it boost more then 15 with it off, i'm just saying it boost way past 4. when i vagged it it said about battery because i disconnected it to try and reset everything, also that my coolant sensor was bad. I don't throw a cel that's what makes it even more confusing.

pipe- does yours boost without the wastegate line in limp mode?

quattro- if it uses actual pressure from the n75, should I try a manual boost controller and if so how do i set up the vac lines. Since there is one from the wastegate, one from the wastegate, and one that goes into the intake when most mbc that I see only have two vac ports?

thanks guys for such a quick responce

AudiRacerS4
04-01-2007, 08:44 AM
DBC cars or cars under the year 2000 don't have limp mode due to high boost. The only way DBC cars go into limp mode is if the MAF dies or is unplugged or if the N75 fails or is unplugged

superman_006
04-01-2007, 09:03 AM
I can't figure out why my Giac chipped car will not boost past 4 psi. If I pull the vacum line on my wastegate it will boost 15-20. I know a vw/audi speciality shop and he sold me a used wastegate for $20. That didn't work and I also tried a different n75, checked for boost leaks, and vag-com. Should I try a mbc to bypass a n75 or is there a reason why it will boost like crazy with the vacum off and not with it on. Did I get another bad wastegate? Can you pull the vacum off and still boost past 5 if you are in limp mode? Any help would be awesome. I'm getting so frustrated with this ongoing problem.

Did the shop sell you a wastegate or a wastegate accuator?
As we quattro16 mentioned your wastegate is closed while its just sitting there and it opens when the boost is on the accuator side. If you have the stock turbo (K03) the wastegate spring opens ~5psi, which sound to me like whats going on. On the chipped computer the N75 doent apply boost on the accuator till its built up , allowing the boost to build farther. I would check the N75 hoses, the one that comes staight from the top goes to the wastegate accuator, and the one coming out of the side goes to the turbo housing and the bottom goes dirrectly to the TIP. You shouldnt just unplug the wastegate accuator, its will boost crazy and probly break something, however if you do unplug it and rev it once you sould see more than 5psi of boost on your gauge.. this will be checking your accual wastegate. You can check your N75 valve by trying to blow though it, blow though the side and nothing should come out of the top

AudiRacerS4
04-01-2007, 09:11 AM
^^ the wastegate opens at 10psi. Your wastegate may be stuck open, do you hear any rattling noises when you let off teh gas?

mike-2ptzero
04-01-2007, 10:55 AM
^^ the wastegate opens at 10psi. Your wastegate may be stuck open, do you hear any rattling noises when you let off teh gas?

OEM wastegate actuator comes with a 5psi spring. This means if you bypass the N75 and run a direct line to the actuator from the pressure side of the turbo the wastegate will open to produce no more then 5psi since it will open 100%.


If you run no line to the actuator the turbo will boost up as far as it wants till the wastegate cracks open on its own because of the increased pressure against the wastegate opening and the flow resistance is less going thru there vs going thru the exhaust wheel.


If the turbo will produce high boost with no line but very low boost with the N75 still being used then the problem has nothing to do with the wastegate.

superman_006
04-01-2007, 12:56 PM
^^ the wastegate opens at 10psi. Your wastegate may be stuck open, do you hear any rattling noises when you let off teh gas?

If the wastegate was stuck open the K03 with produce no boost

dozentrio
04-01-2007, 01:13 PM
did you do a topic search??

try disconnecting your battery, then throttle body, then unplugging your ECU. Then plug back in, in that order. Not sure why it works, I'm sure there's superfluous steps in there, but it worked for me. GIAC chipped k04. ndbw. Good luck. Let us know if it works

b5power
04-01-2007, 04:02 PM
DBC cars or cars under the year 2000 don't have limp mode due to high boost. The only way DBC cars go into limp mode is if the MAF dies or is unplugged or if the N75 fails or is unplugged

But when a car does go into LIMP mode cause of the N75 or the Maf dies, wouldn't there be a CEL

cleanandsimple
04-02-2007, 05:05 PM
yeah what b5 power siad, how come there is not a cel and runs perfectly fine just won't go over 5?

1.8TurboAudi
04-02-2007, 05:57 PM
maybe the MAF ?

4ringAR
04-02-2007, 06:10 PM
i hate boost!

http://www.ten8teen.com//catalog/images/ILoveBoost_042106.jpg

sorry i'm no help. i dont know too much technical-wise.

Matt@JHM
04-02-2007, 06:16 PM
Get an air compressor at around 6 PSI and blow it into the line connected to the wastegate actuator. If the wastegate slams open, the actuator is dead. Good luck.

mike-2ptzero
04-02-2007, 08:06 PM
Get an air compressor at around 6 PSI and blow it into the line connected to the wastegate actuator. If the wastegate slams open, the actuator is dead. Good luck.

That really doesn't make sense seeing that the rating on the actuator spring is 5psi.

superman_006
04-02-2007, 08:10 PM
Get an air compressor at around 6 PSI and blow it into the line connected to the wastegate actuator. If the wastegate slams open, the actuator is dead. Good luck.

this would show the accuator's working

Audi A4 1.8T
04-03-2007, 05:40 AM
im having the same prob, and have been for months and months. Once about every two weeks i can boost 15-20 psi. Im chipped by the way. Once im boosting that much, if i get on the throttle to much, the car acts like its overboosting, and immediatley goes back to limp mode. once in limp mode i range from 2 psi-7 psi. but it feels like 0 psi. i dont know what the hell it is, i have a new maf. hell i dont even have a cel. so i guess maybe the n75 is hooked up worng. its only got about 10 k on it.

mike-2ptzero
04-03-2007, 07:49 AM
im having the same prob, and have been for months and months. Once about every two weeks i can boost 15-20 psi. Im chipped by the way. Once im boosting that much, if i get on the throttle to much, the car acts like its overboosting, and immediatley goes back to limp mode. once in limp mode i range from 2 psi-7 psi. but it feels like 0 psi. i dont know what the hell it is, i have a new maf. hell i dont even have a cel. so i guess maybe the n75 is hooked up worng. its only got about 10 k on it.

Car wont always throw a CEL for limp mode. The ecu will also limit how much the throttle body will open if you over boost too many times. If you have a vag you can check to see how much it opens by logging block 054.

Audi A4 1.8T
04-03-2007, 08:53 AM
yeah my buddy has one. lets say i vag it, and there is throttle cut from the ecu. then waht do i do. tba?

mike-2ptzero
04-03-2007, 09:35 AM
yeah my buddy has one. lets say i vag it, and there is throttle cut from the ecu. then waht do i do. tba?

Then vag block 115 after clearing all the codes and doing a throttle adapt(block 060). This way you can see when the car is over boosting and then try to figure out why at that point.


You might want to try running a line directly to the wastegate bypassing the N75 valve to see if the boost will stay right at 5psi. Also check your hoses to and from the N75 to make sure there are no kinks or leaks.

Audi A4 1.8T
04-03-2007, 10:54 AM
Yeah i will do that, im starting to wonder if somehow the n75 is the culprit. Like i said b4 its pretty new, but the lines were kinda rigged.

cleanandsimple
04-03-2007, 01:26 PM
i think that might be mine problem, i just vagged it today and the only one that came up was n75. i'm thinking either the new/used one doesn't work or i don't have the lines right. there should be a "my car is chipped and still won't boost" club because it's so frustrating to do it by yourself

cleanandsimple
04-03-2007, 01:28 PM
by the way thanks guys for all the help and all the quick responces

Audi A4 1.8T
04-03-2007, 01:42 PM
I think my prob is, i rigged a n75 line. the hose that has two ends with diff diameters was rigged. so im thinking thats my problem.

iwasawesome
04-04-2007, 02:01 AM
I can't figure out why my Giac chipped car will not boost past 4 psi. If I pull the vacum line on my wastegate it will boost 15-20. I know a vw/audi speciality shop and he sold me a used wastegate for $20. That didn't work and I also tried a different n75, checked for boost leaks, and vag-com. Should I try a mbc to bypass a n75 or is there a reason why it will boost like crazy with the vacum off and not with it on. Did I get another bad wastegate? Can you pull the vacum off and still boost past 5 if you are in limp mode? Any help would be awesome. I'm getting so frustrated with this ongoing problem.

do you have the n75 oriented the right way ?

Long side into the TIP... right goes to waste... left goes to charge.. if you are looking at the electrical connection

iwasawesome
04-04-2007, 02:02 AM
im having the same prob, and have been for months and months. Once about every two weeks i can boost 15-20 psi. Im chipped by the way. Once im boosting that much, if i get on the throttle to much, the car acts like its overboosting, and immediatley goes back to limp mode. once in limp mode i range from 2 psi-7 psi. but it feels like 0 psi. i dont know what the hell it is, i have a new maf. hell i dont even have a cel. so i guess maybe the n75 is hooked up worng. its only got about 10 k on it.

same thing happened to me for a bit... torn L hose. No CEL.. just limp mode.. tons of boost then limp. check it out

Audi A4 1.8T
04-04-2007, 09:10 AM
iwasawesome, would the boost og back n forth. meaning would you be in limp one day then boosting normal again the next, then back to limp? so on and so on.

dozentrio
04-04-2007, 09:24 AM
Have you tried unplugging and plugging the ECU back in? My car is a '97 as well. I went through -everything- that you have. Replaced n75, checked for boost leaks, worried that my wastegate was fucked, scanned and re-scanned my car. Try unplugging your ECU, it takes 5 minutes-- what can it hurt.

Audi A4 1.8T
04-04-2007, 11:23 AM
how long did u unplug it for? im a 00 ndbw so i dont know it will help me but my help the other guy.

dozentrio
04-04-2007, 05:20 PM
unplugged for about a minute. A second would probably do it. My theory: the ECU stores information somehow, even with battery unplugged? Unplugging it is a clear all. Using the VAG to clear the codes may not be enough? anyway, it worked for me :P

probably a ndbw fix though

mike-2ptzero
04-04-2007, 05:58 PM
unplugged for about a minute. A second would probably do it. My theory: the ECU stores information somehow, even with battery unplugged? Unplugging it is a clear all. Using the VAG to clear the codes may not be enough? anyway, it worked for me :P

probably a ndbw fix though

If you unplug the ecu or batter does exactly the same thing since there is no power in the ecu at that point. Problem with unplugging the battery is you have to deal with the "lock out" code for the radio.

When doing either make sure to do a throttle adapt before starting the engine.

dozentrio
04-05-2007, 12:36 AM
hmmm... yes, I forgot to mention turn the key to accessory for about a minute before starting the car [:D] I did that, perhaps it was the key step?

My problem was probably throttle body related in some way. My battery died on me, and the car was in "limp" mode afterwards, even though ndbw doesn't hvae limp mode. So we tried to do a Throttle Body Adaptation, and some error came up and afterwards the car wouldn't start. -Then- I started getting throttle body CEL codes. Replaced the TBA, no change. Unplugged the ECU, waited for a minute with key in accessory (this supposedly does a throttle body adaptation of some sort.. not as thorough as with VAG though) and then it worked.

Anyway, the reason I suspect GIAC chips cause this problem is because the other guy who fixed his car by the aforementioned method, was also GIAC chipped. And my car's prevoius owner once -replaced- the ECU because of a throttle body problem (which wasn't solved by replacing it) ... So it seems that GIAC chips cause some kind of weird limp mode on ndbw cars and it's fixed by either performing a proper TBA, or replacing the ECU :P or just unplugging it. At any rate, i hope you figure out what your car's issue is

mike-2ptzero
04-05-2007, 06:18 AM
hmmm... yes, I forgot to mention turn the key to accessory for about a minute before starting the car [:D] I did that, perhaps it was the key step?

My problem was probably throttle body related in some way. My battery died on me, and the car was in "limp" mode afterwards, even though ndbw doesn't hvae limp mode. So we tried to do a Throttle Body Adaptation, and some error came up and afterwards the car wouldn't start. -Then- I started getting throttle body CEL codes. Replaced the TBA, no change. Unplugged the ECU, waited for a minute with key in accessory (this supposedly does a throttle body adaptation of some sort.. not as thorough as with VAG though) and then it worked.

Anyway, the reason I suspect GIAC chips cause this problem is because the other guy who fixed his car by the aforementioned method, was also GIAC chipped. And my car's prevoius owner once -replaced- the ECU because of a throttle body problem (which wasn't solved by replacing it) ... So it seems that GIAC chips cause some kind of weird limp mode on ndbw cars and it's fixed by either performing a proper TBA, or replacing the ECU :P or just unplugging it. At any rate, i hope you figure out what your car's issue is


ndbw and dbw have a limp mode, this can happen for many reasons but the dbw has plenty more. Most likely your issue was the throttle body position was exactly correct with what the ecu thought it was so when you did the TB adapt with the key it ended solving the problem. If you tried to do the TB adapt the first time with the vag you might have used the wrong block since there are 2 different blocks(60 and 98) to use for the ndbw cars and 60 doesn't always work on all of them but is the correct block for the dbw cars. It also seems like the ndbw does not do the TB adapt every time the key is turned on like the DBW cars do, which is why you must unplug the battery or ecu when you want to do a TB adapt with the key method.

cleanandsimple
04-13-2007, 03:53 PM
i finally am boosting! i just don't think it's right. shouldn't a ko3 have quick excelleration since it's such a small turbo? mine won't start boosting till the higher rpms and sounds like the wastegate or something is dumping air like crazy. first gear will only boost to around 6, second will boost alittle over 10 and then anywhere from 15-20 in the rest of the gears. i think the n75 is still messed up, the only port when blown into that doesn't leak air is the longest going into the inlet pipe. i'm glad i'm finally boosting but don't want to mess shit up. thanks for all the help before

maxspeed
04-13-2007, 05:21 PM
If you unplug the ecu or batter does exactly the same thing since there is no power in the ecu at that point. Problem with unplugging the battery is you have to deal with the "lock out" code for the radio.

When doing either make sure to do a throttle adapt before starting the engine.

my car has never asked me for a lockout code, could it be because im down to valet keys?

(lost one key snowboardin, the other one hiking [headbang] [headbang] )

theskuh
04-13-2007, 05:46 PM
only the bose has the lockout code. I freaked out when I did the Timing Belt tying to find the code for my radio.One wasn't in my glovebox. Then found one post saying it was only the bose that had the lockout.

seatown88
04-13-2007, 05:55 PM
only the bose has the lockout code. I freaked out when I did the Timing Belt tying to find the code for my radio.One wasn't in my glovebox. Then found one post saying it was only the bose that had the lockout.
really ony the bose has the lockout code?

theskuh
04-13-2007, 05:59 PM
I believe so, I had my battery off for a couple days during the TB and radio memory was wiped but no code. I have the symphony deck.


edit -- i dunno I looked at this page and says the concert has some sort of smart code and the symphony has a code too??? dunno

http://www.ibiblio.org/tkan/audi/radios/

seatown88
04-13-2007, 06:19 PM
hmm its annoying not having the code, but my guess is that i need it, i have the delta cc and i hate it