My problem is that the turbo boost is all over the place.. 0,5-2bar...

I have new:
N75
Air flow meter
Mitsubichi TD04-15t turbo
i don't find any leaks...
new chip
no fault codes..


Please help me, i have spent allot of money on this problem now.. =(


tanx for your help!


hope you understand my bad english,, i'm from sweden so,,,

The Car:
Audi A4 1,8TQ -96

 

Need more info.
How many bar is the car supposed to run?
Have you checked the wastegate operation? Is it sticking?
Have you checked the the fuel side? Injectors, fuel pump, fuel filter, fuel pressure regulator, etc.

 

The fuel side is ok...

when i chipt it i was told that the pressure sould be 1bar, max 1,1bar...
(orginal 0,5 bar)

when i dont have the n75 conected i have 0,5bar... so i think the wg is good.... or could it be the spring?

can the open dump do it?

 

if your able to spike to 2bar (29.4psi) I'd say you have a wastegate or actuator issue. Run a vacuume line from the wastegate actuator into your car with a vacuume pump (hopefully you have access to a good one that will do pressure too) and drive your car around manually controlling the wastegate and see what your boost does.

 

You probably have a boost control issue related to the N75 or wastegate. Check to make sure none of the vacumm lines to the N75 or wastegate are kinked. My guess is that one of the vacuum lines is kinked causing you to overboost. Then the overboost is causing the car to go into limp mode (0.5 bar boost pressure).

 

whoa whoa whoa.. you have a TD04-15t TURBO? WTF?

 

GeilKyle2:
I dont have anyting i can test that whit.. =/ but i can fix somthing...

dafrazi:
The N75 is new, and all the vacuum lines.... no limp mode... i get 0,5bar when i disconnect the n75...

InsaneHatter:
Yeah... it's real fun *not* if i got it to work i think it's good.. but...
and by the whay, it's not me that put it in.. it was the last owner... =(

 

The problem is , depending on your tune, the compressor maps on a TD04-15t and k03 are different.

Maybe your DV is shot.... if could be spiking, then the dv cant hold the boost it drops it. and such a big turbo might put your MAF readings really high.. i dont think this will cause limp, but maybe.

 

It is normal to only get 0.5 bar with the N75 disconnected. When the N75 is disconnected the car goes into limp mode.

For me to get over boost like that (1 bar over requested boost) I would need to disconnect the vacuum line to the wastegate. This makes me think that you have a problem with the N75 or wastegate. The N75 valve should keep you from overboosting so far above what the program is written for.

Kinked doesn't mean broken or torn, it means that the vacuum hose may be bent so far that it cuts off flow...similar to when you get a graden hose twisted and the water stops flowing.

 

dafrazi
Ok, i have checked the lines and its no problem i can find there...
and the n75 i new so it sould work i hope...

InsaneHatter:
Ok, are there mutch differens? becuse when i chipt it they told me it wasent a big diffrense so they chip it as if it was a k03 in it...
The DV is shot, what is the DV? spiking is no good =(