Intermittent Turbo's

[Steviescottish]

Hi Guys.
I am having a small problem with my turbo's!
When i start the car it runs as normal, turbos working as normal etc.
Around ten minutes into the journey, the turbo's fail to come in as expected. The journey will continue with no turbo boost.
If I stop the car and start it again, i will get boost as normal, but again, a short period later the turbo's fail to kick in until the engine is turned off.
I have noticed that the aux fan comes on nearly on all journeys. Is this normal? Is that just due to summer climate?
Is there any connection between the two?

Any help would be appreciated.

Thanks.

[jimbo1234567]

you need to get it scanned, chanced are its got a dead egt sensor

[Steviescottish]

Hey Jimbo.
My mate has diagnostics gadgy but is on holiday.
Is this easily changed without going to the dealer?

[jimbo1234567]

yes its not too hard but its the maf that kills the egt sensor because it goes off and makes the car run lean and takes out the egt and lambda sensors

[ddidds]

hi

i had the same problem. it's nothing complicated. the error is n75. Waste Gate Frequency Control Valve

it is a device that controls the waste gate's on your turbos. when they are old they get temperature sensitive and when they heat up they stop working properly and this way the computers cuts off the turbos completely
only one was faulty but i changed both which is what i suggest you should do aswell. they cost around 20 euros each here in Romania
this is how the part looks like

http://www.ecstuning.com/Audi-B6_A4-FWD ... cal/ES122/

cheers

Alecs

[jimbo1234567]

theres only one n75 valve.

[Steviescottish]

Thanks for the info guys.
I will do a bit of investigation and see what the score is.
If i need a n75 valve then will just get a genuine Audi unit although it breaks my heart going to the stealer!
Is there a tried and tested aftermarket alternative?
Any suggestions?

[jimbo1234567]

just get an original part they are £40 ish. although i dont think thats your problem

[Steviescottish]

Apologies for my ignorance, what is the EGT sensor and where is it located?
Is this best done at the dealer or can my mechanic friend cope with this easily?
Any info you can pass on will be appreciated.

[lynchy]

If you are based in scotland take it to a specialist maybe www.starperformance.co.uk for a going over could be faulty MAF, egt senser and lambdas all connected to a faulty MAF over time also you could still have oem diverter valves which are 710A which everyone changes for the better ones 710N`s

[ddidds]

theres only one n75 valve.

the mechanic told me he changed "both" ... maybe he charged me twice, common practice over here...

i had the same symptoms and in my case this valve was the problem, dosen't have to be the same solution or problem for Steviescottish

[Nige_RS4]

theres only one n75 valve.

the mechanic told me he changed "both" ... maybe he charged me twice, common practice over here...

i had the same symptoms and in my case this valve was the problem, dosen't have to be the same solution or problem for Steviescottish

Maybe he meant the DV's or bypass valves as they are called on these cars?? Do you have a part number?

[jimbo1234567]

Apologies for my ignorance, what is the EGT sensor and where is it located?
Is this best done at the dealer or can my mechanic friend cope with this easily?
Any info you can pass on will be appreciated.

there are 2 egt sensors and they monitor exhaust gas temperature, they are bolted onto the rear of the inlet manifold on the left hand side. they are 2 boxes bolted back to back about the size of a matchbox each . a black one and a reddy brown one, each has a braided wire that goes to the probe that screws into the exhaust manifold just before the turbo, theres one for each bank.