how can you tell if your turbo is going bad...its not doing anything
12-12-2002, 01:36 PM
#1
AudiWorld Super User
Thread Starter
Join Date: Mar 2001
Posts: 7,735
Likes: 0
Received 0 Likes
on
0 Posts
how can you tell if your turbo is going bad...its not doing anything
obvious but I'm not really getting more then 10psi of boost. I've checked everything I can think of but nothing helps.(n710,n75,mas,o2's, leaks, plugs,codes,) I'm replacing the fuel filter as a last effort but i doubt that will help. if I clamp the wastegate hose shut I can overboost but I dont want to do that. what can go wrong with the wastegate and how can I check? thanks
12-12-2002, 04:22 PM
#2
AudiWorld Super User
Join Date: Mar 2000
Posts: 3,359
Likes: 0
Received 0 Likes
on
0 Posts
If your turbo was "blown" you would have zero boost...
...the only thing I can think of (assuming you have checked EVERYTHING) is a busted wastgate actuator arm. That would cause a really bad turbo lag and somewhat limit the top end boost.
From your description, however, it sounds like you may have a tear in a hose downstream from the turbo. The wastegate recirc hose can go bad and cause what you are describing. Do you hear a hissing sound at full throttle?
Mike O.
From your description, however, it sounds like you may have a tear in a hose downstream from the turbo. The wastegate recirc hose can go bad and cause what you are describing. Do you hear a hissing sound at full throttle?
Mike O.
12-12-2002, 04:46 PM
#3
AudiWorld Super User
Thread Starter
Join Date: Mar 2001
Posts: 7,735
Likes: 0
Received 0 Likes
on
0 Posts
I doubt its the actuator arm becase I'm still getting 12psi peek
& if i had @ leak I dont think it would hold 10psi like it does.. I may just swap out the ko3 with a friends used one and see what happens.. but I would like to avoid that if poosible.. what I need is some new ideas on thinks to check.
Trending Topics
12-13-2002, 08:22 AM
#9
limp is a lot lower since the ECU doesn't modulate N75 anymore. I'm speculating...
exhaust gasket leak or manifold crack, wornout turbo or leaking wastegate.
I couldn't believe a small hairline manifold crack on a DSM caused a 4 psi loss but it did on my coworker's car.
It's still good to check that there are no intake leaks after the MAF and also that the MAF is not peaking anywhere at a low number - example between 70 to 80 g/s (about 1.5V maybe) which could indicate a MAF going kaput.
The fact he's getting boost spikes means that the ECU is still comunicating with the wastegate via n75.
probably a good idea to swap chips too in case the ECU forgot how to use sensor readings ;P
I couldn't believe a small hairline manifold crack on a DSM caused a 4 psi loss but it did on my coworker's car.
It's still good to check that there are no intake leaks after the MAF and also that the MAF is not peaking anywhere at a low number - example between 70 to 80 g/s (about 1.5V maybe) which could indicate a MAF going kaput.
The fact he's getting boost spikes means that the ECU is still comunicating with the wastegate via n75.
probably a good idea to swap chips too in case the ECU forgot how to use sensor readings ;P
12-13-2002, 08:30 AM
#10
do you have an air compessor? get a 2" PVC cap from the hardware store...
they are caps for those white 2" PVC water pipes. Buy a air hose fitting and screw it in the cap after making appropriate hole. Seal treads with epoxy or my favorite - goop. Pressurize air compressor to about 15-20 psi. Remove air box (including MAF) and plug cap in there.
Get a spray bottle with soapy solution and spray all intake hoses - turbo, I/C, intake, etc while air is applied.
There are two places the air will normally leak, so don't worry about the hissing sounds and burbling you hear inside the engine - some will escape past the throttle into whatever cylinder has open intake valves, and some will escape through turbo bearings since some turbos use the oil pressure and turbo rotation to obtain a good seal.
Get a spray bottle with soapy solution and spray all intake hoses - turbo, I/C, intake, etc while air is applied.
There are two places the air will normally leak, so don't worry about the hissing sounds and burbling you hear inside the engine - some will escape past the throttle into whatever cylinder has open intake valves, and some will escape through turbo bearings since some turbos use the oil pressure and turbo rotation to obtain a good seal.