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View Full Version : blown wastegate? what are the symptoms???



bbkid43
06-27-2007, 10:12 PM
I've been having this problem for quite a while.

I have a 2001 A4 1.8TQM 80k miles on the clock with a GIAC chip,borla exhaust, and evoms dv.

I used to spike at 21psi and hold 19-20psi. It now will only spike to 15psi and will drop down to around 10psi. It will surge and hiccup when I'm on half throttle. It seems like the car is trying to go and smoothly hit boost and then it just stops suddenly. It seems to be happening around 2500-3000 rpms.

I have no codes and am not in limp mode.

I've done the following:

Ngkbkr6e plugs gapped to .028
new maf sensor
new n75 valve
pressure tested twice not a single leak anywhere
software reflash


I checked the turbo for shaft play and it doesn't seem like there is any noticeable problem. This is really frustrating as it has been going on for a few months now. Not even shops can figure it out.

My only guess is a bad wastegate or bad map sensor. When I vag com'd the car the map sensor altitude stayed at -4.7 and didn't change while driving...I cleaned it last night with rubbing alcohol and there still was no difference.


What do you think guys? Anybody else out here with this problem? Any feedback would be great!

bbkid43
06-27-2007, 11:13 PM
Just tried taking off the vac line on the wastegate...the car boosted up to 21psi again and felt great but didn't feel as powerful like it used to...also i took out the o2 sensor and it was covered in white.

I'm leaning towards a bad wastegate????

bbkid43
06-28-2007, 10:49 AM
bump

bbkid43
06-28-2007, 02:58 PM
Nobody has ever had this issue?

Audilover08
06-29-2007, 03:32 AM
Wish I knew the answer...suprised nobody here is helping you though?

bbkid43
06-29-2007, 04:29 PM
bump...

bOOOOstedAudi
06-29-2007, 04:35 PM
i just had that same issue almost perfect
It was my 02 sensor and it didnt even throw a code

pipe7284
06-29-2007, 04:43 PM
shit, i am having the same exact issue. i still dont know what it is.
what vacuum did you disconnected and connected to what , or what?

blackaudia4tk
06-29-2007, 05:24 PM
if you thought it was the wastegate actuator you could put a vacume guage and pull a vac and see it holds it or can even pull one...does it rattle on decereration thats what mine did and the wastegate was lose. you might just have to adjust the threaded bolt on the actuator rod to make it a tighter fit.. it might be lose and letting pressure go by just from use.. just some thoughts

Bic-Ball
06-30-2007, 03:05 AM
this is the thread i made that lead me to the conclusion that my wastegate was bad:

http://www.audizine.com/forum/showthread.php?t=132402

my wastegate flap came off the turbo and is chilling in my exhaust somewhere. by that happening the turbo turbine got no flow and i had no boost. you could also have a bad wasategate actuator, im not exactly sure what's different between the two problems they should be similar, however you can but a new actuator assembly instead of a whole new turbo due to the flap.

to establish that mine was the wastegate i did the same thing as already mentioned, i disconnected the wastegate actuator to leave the wastegate flap permanently closed and then i drove around. my boost gauge read 0 psi when i slammed the gas so i know the turbo was making no boost. it was a huge relief when i took my old turbo off and i saw the flap was gone. :)

here's a pic of the old and new turbo side by side
http://www.zeroproof.com/bicball/twinturbos.jpg

audiFUEGO
08-07-2007, 12:14 PM
bump this....

Im having the EXACT same problem.

Please help...

HIERLEVELZ
08-07-2007, 12:26 PM
if you thought it was the wastegate actuator you could put a vacume guage and pull a vac and see it holds it or can even pull one...does it rattle on decereration thats what mine did and the wastegate was lose. you might just have to adjust the threaded bolt on the actuator rod to make it a tighter fit.. it might be lose and letting pressure go by just from use.. just some thoughts

Can the wastegate nut be easily accessed? It seems like there is little or no room there to adjust it w/o removing the entire turbo.

pinky
08-07-2007, 12:48 PM
blown wastegate results in boosting 0-1psi...

AudiRacerS4
08-07-2007, 05:28 PM
Can the wastegate nut be easily accessed? It seems like there is little or no room there to adjust it w/o removing the entire turbo.

you can reach it from underneath the car with a long extension from the wheel well and a wrench from right underneath the turbo

audiness
08-07-2007, 06:00 PM
do you have the AWM eninge?

seatown88
10-17-2007, 10:31 PM
im having this problem right now as well, i just got chipped and it will hold about 13 psi, its not the maf and its not a leak so im really leaning towards wastegate actuator. I do have wastegate rattle under deceleration. if i tighten up the wastegate will my psi go up or do i need a new actuator? im gonna double check that it is the wastegate by unpluging the actuator and seeing if pressure increases.