turbo wastegate

[4udi]

hi to all i have been told by a mechanic that my wastegate stays in the open position thats why i have my boost/limp mode problem just wanted to know a few things
my car is an audi a4 afn 1.9 tdi 110

a)is the turbo a garretts vnt15
b)can the wastegate be sorted out without changing the turbo
c)should i get a second hand turbo or a reconditioned one buying a new one is out of the question
d)are there any other makes or should i stick to the original

p.s i have been through every thing else i.e pump,injectors, maf and the mechanic has said it is definately the wastegate

thanks

[gazza3733]

you could try turbo technics.com they reconditioned my turbo they collect and returned for less than 300 quid give them a call they will answer your questions.good luck

[adamss24]

hi to all i have been told by a mechanic that my wastegate stays in the open position thats why i have my boost/limp mode problem just wanted to know a few things
my car is an audi a4 afn 1.9 tdi 110

a)is the turbo a garretts vnt15
b)can the wastegate be sorted out without changing the turbo
c)should i get a second hand turbo or a reconditioned one buying a new one is out of the question
d)are there any other makes or should i stick to the original

p.s i have been through every thing else i.e pump,injectors, maf and the mechanic has said it is definately the wastegate

thanks

You should go to another mechanic as the turbocharger on the 110 AFN engine is a VNT and it does not have a vastegate, however the VNT mechanism might be clogged with carboon/sooty deposits and wont move freely, hence the overboost/limp mode condition... They can be cleaned with mixed results... I would give the car a blast on the motorway first, then remove/clean the turbocharger and see if its improves.

[Teflon]

Adamss24 is right, there is no wastegate on the diesel turbo and the VNT mechanism loves to stick. There are lots of other causes for limp mode and I checked for all of them them before I finally whipped the turbo off and cleaned it out. Took about 2 hours.

I suggest you post your symptoms (including when & what revs the problem comes on and whether it is reset when you turn the engine off), plus your mileage & other info and we'll see if there is some better advice than what you got from the mechanic!

[4udi]

thanks for the replies to start with revs go past thee 3000 mark in 1st and 2nd gear then in 3rd after 3000 mark it jerks back and does not exceed that mark through 4th and fifth i've done 15000 miles like this present 140k plus error code 0550 start of injection control timing

list of things done

timing belt
3rd injector nozzle
pump replaced (second hand)
pump re calibarated
pedal position sensor
all timing redone again
new cat
tried new maf for 3 weeks
on my 3rd mechanic

after all this been told its turbo wastegate is in the open position thats why boost problem by an independent audi specialist after he redone the timing and had the pump recalibarated as the timing was too advanced (wish i was a specilist) i am just throwing money at the moment and have had enough sorry for the long bore

[4udi]

the independent audi specialist should have known if the turbo had a waste gate or not yet he clearly told me it was in the open position and said you have to buy it with the turbo unit £680 plus 3 hours labour worth half the car

[adamss24]

Where abouts are you ? Is the yellow coil flashing on the dash when the car goes in limp mode ? If you are close to London i could have a look on the car. The fault code you have points to an incorect pump timing. They need fine tweaking after pump fitting. Your pump is either too advanced or too retarded. How does it starts on a cold morning ? It could also be an old fault prior fitting the replacement pump. The turbocharger's jammed VNT mechanism should trigger an boost fault. If you come to me i can tell you whats wrong as i need to see some log-ins from the car and monitor the live data stream from the pump to the ECU. Hope this helps...

[Teflon]

the independent audi specialist should have known if the turbo had a waste gate or not yet he clearly told me it was in the open position and said you have to buy it with the turbo unit £680 plus 3 hours labour worth half the car

If they are telling you there is a wastegate, they shouldn't be trusted with anything more technical than paper and crayons. You can pick up a fullly reconditioned turbo for half the cost he is quoting.

Your symptoms point to overboost, either due to sticking VNT or a MAP sensor problem (or boost sensor as Audi likes to call it) but the fault code says otherwise. Adamss24 clearly knows what he is on about so you should fix the pump problem then look at fault codes again. No need to monkey with the turbo unless you get something like "manifold absolute pressure error".

If it is any consolation, I went through half a dozen ideas for the problem from professional mechanics before I solved it myself with help from this forum and others.

[4udi]

the error code was present before all the timing and pump calibaration were done after that the independant specialist told me it was the turbo

[Teflon]

Time for a new error code reading then and let's see what it says now.

Time too for a new mechanic. If the old one insists it is the wastegate, it would be a good idea to ask him to show you where on the engine it is. Then take a photo and post it here. I'd love to see if he is getting confused with the spangle flange or the throstlewit.