Loss of Power :/ - Page 3

Adrian E · #21 21st October 2015, 11:17 AM

It needs further investigation by someone who understands basic faultfinding procedures and has decent diagnostic tools.

I wouldn't waste your time changing parts until it's been established if you have one or more underlying faults.

ElsaWIN suggests there's a procedure for checking the actuator, which involves fitting a new link and confirming the turbo actuator is free and moves to where it's supposed to based on electrical signals received from the control unit.

This thread looks very similar in terms of symptoms and fault codes

http://www.vwaudiforum.co.uk/forum/s...den-Power-Loss

It needs to go to a proper VAG specialist with the necessary tools - the VAG tool for testing the control unit is 'Tester for E-positioner -VAS 6395-'

evo · #22 21st October 2015, 01:12 PM

Thanks mate did have a look at that and will try to find a specialist in Birmingham by Friday to have a proper look at it. Central VW Audi told me £72 just to plug it into their machine... so not happy with that.

Anyway... I did some investigating...

I found that there are two actuators in my car, one at each side, and perhaps this is where I am hoping for some insight from you guys...

On one side, when the engine is off, the actuator is in the "up" position... but the other side is in the "down" position.

When the engine is on - the side that was "up" is pulled down, and only goes back up when I rev the car...

The other side however which started in the downward position does not move from its "down" position - so it remains there, and even under revving it does not move.

Could this be the issue? Or is this merely normal operation?

Delboy · #23 21st October 2015, 01:54 PM

I'm not familiar with the Diesel engines but it would be a fair safe assumption that on v engines that actuators would behave the same on opposite sides of the engine, possibly in mirror to the other side but if one moves while revving and the other doesn't then it would point to an issue with that area.

Can you swap the items to see if the fault moves

ainarssems · #24 21st October 2015, 02:06 PM

That will probably be fault code 12597 intake manifold runners on 1 side

evo · #25 21st October 2015, 06:51 PM

Okay cool info guys thanks

And yeah if that is that particular fault, would you think that this could be the reason for no power in the car? Or that there is another issue (the 13128 error?)

snapdragon · #26 21st October 2015, 07:49 PM

If the DPF was blocked, you would almost certainly have a warning on the dash and fault codes. It has temperature probes and back pressure sensors. It sounds like one of the inlet manifold flaps is broken for sure. I'm don't know if that causes your power problems, but it cant help. I have read about repair kits, but never had any experience of the problem myself *touch wood*.

evo · #27 22nd October 2015, 03:23 PM

Well some developments.

Definitely not DPF, as no warnings on the dash as snapdragon indicated.

I swapped the actuators for the inlet manifolds around from right to left to see if that moved the issue to the other side (thus pointing to a dodgy actuator) but that didn't do anything. The problem of the falling actuator happened still on the same side.

Took off all the ducting and pipes, and looked inside the manifold to see if the flaps were freely opening and closing when I manually moved the actuator - which they did.

It appears that the car is trying and failing for some reason to move the actuator on that one side, and instead defaults to leaving the manifold flaps open.

Again not sure if this is the issue or not -as the engine runs smooth still, and it should be turbo-ing up when I run it still. However that is not the case.

I also took off the turbo and had a look inside, its moving freely and is super clean. The actuator is also free to move around on there.

So basically, here I am - with not a clue in the world of what it could be though I know its going to be some small gremlin.

The real problem is this - I have agreed to part ex this car (before the turbo fault) for a new car. They gave me a low trade in value but I was happy as I was so excited to change car.

Now the issue is quite simple - I doubt they're going to take the car like this... and I don't have the px value they offered to me available in cash to continue the deal with them without the traded-in A8.

So I'm stuck... any ideas people? Or anyone want a bargain A8 if they know how to fix this issue?!

Mechcanico Lee · #28 22nd October 2015, 08:23 PM

The inlet manifold runners do a sweep when ignition is switched on , so like you say you see the arm go up and down , in a good working condition each manifold motor does its sweep and the ecm does a signal compare between the both of them , if one of them fails the sweep test the ecm will switch that motor off line .

Biggest issue here is where the link rod attaches to the manifold arm the plastic end stops break off hence the codes .. upper limit/ lower limit not reached ....look at your code ,it's telling you just that .

There is link rod repair kits on eblag but the ones I have done always needed manifolds , the manifolds are on eblag aswell but I don't know what the quality is like ??

In the cases I have seen the manifold runners have NOT put the car in limp ...just put the management light on , depends on year and software level with limp issue

Next code ... turbo control .....
Is it vaccum control actuator or electric (hella unit)
If vaccum , with engine running take vac the pipe off the acctuator .... is there vaccum on the pipe , if yes when you put it on the acctuator can you see the vnt acctuator arm being pulled up to the stop screw.

If there is no vac on the pipe , trace the pipe back to the control solenoid , see if the control solenoid has its vaccum supply to it , systems normally have a vac resvoir somewhere which is kept under vaccum from brakes vac pump .

If the turbo control is electric , start and stop the engine whilst watching the turbo acctuator arm , it should do a self test sweep , if no sweep next tests would be wiring checks on the plug , dont want to go into that yet , just work through the procedures I have said
What year is yours by the way ?

Mechcanico Lee · #29 22nd October 2015, 08:31 PM

Sorry just seen yours is 2008 , the last one I did was on a 57plate , so later models could go into limp because of the manifold runners , pretty sure it will be electric turbo acctuator at that year .
The turbo code could be a consequential code because of the manifold runner , but I still think the turbo acctuator will do a sweep when engine started and stopped , thus proving motor control is working .

evo · #30 23rd October 2015, 12:12 AM

Many thanks for your detailed reply.

The turbo actuator doesn't do a sweep. That's for certain. And as the turbo actuator unit and the two manifold actuators are the same part, I swapped all three around to see if the problem was systematic failure of one of the actuating units... but it isn't - the fault continued in the same place, regardless of which actuator was there.

Leads me to believe the computer (whichever one it may be) is shutting it down after start up on purpose...

I will of course have another play with it tomorrow!