V50 Engine 2.0D : stuttering pulsing power

[yannickc]

Originally Posted by The Thong

What diagnostics are you using?

Vida dice.

But i have a new update. The last repair was not successful.

But today i take my car and take a ride with Vida diagnostics for live monitoring.

Until today i always was looking in the fuel chain.
But today i also want to check other things

While driving while the problem occurs , i noticed a immediate drop of air-stroke reading from the MAF sensor. I found this a bit strange.
Whit the idea this is a fuel problem i dont expect the maf sensor is responding so heavy.

So first i disconnect the maf sensor.
No difference.

Then i disconnects the vacuum pipe from the throttle body valve.
For so far i did some tests today i can tell whit the pipe connected. The problem occurs. And without, no juddering.

The strange thing is, i also replaced the throttle body and checked the valve for sticking... this was al good.
So it looks like its maybe a leak in the vacuum valve that controls the throttle body valve.

For now i disconnect the vacuum pipe to test.
The valve just stays open... And i just put something in the pipe to prevent vacuum leaks.
The car is running pretty ok, but you notice a very big turbo gap.
So it looks like this valve is also used to hold turbo pressure when lifting the throttle pedal.

I let you know the result.
But for now i just wait and see maybe for a week or 2.

[yannickc]

So today i played a little and do some tests with the throttle body valve.

Now it turned out the this valve closes time to time when pushing the throttle.

I did some diagnostics to know what controlles the valve.

It tuns out its not a vacuum leak, and not the "electro vacuum valve" (that controls the throttle body valve).

I'm 100% sure now the electro valve get electrical power and there fore closes the throttle body valve.

So for now i just disconnect the connector from this electro valve.
The car runs without issues now, only the engine stop is not so smooth.
(the throttle body valve needs to close and cut off air flow when putting engine off)

Next step i looking for cable damages that causes a bad connection.

[yannickc]

Ok update ...

unfortunately the signal is coming from the ECU.

Even with disconnected cable on the ECU side AND on the valve side there is still a noticeable performance loss.

It is just like before, but now not as noticeable as before when the air valve blocked the air inlet. So in the mean time it is not so bad to drive with.

With the idea the air valve was controlled from the ECU, And with the fact there are still problems without this means there are also wrong signals to other electrical parts what can cause this performance drop time to time.

But on the other side there are no errorcodes except for the ECM-0002. (very rarely). I also are not able to see strange things in Vida when monitoring.
I measured air pressure, voltages, fuel pressure....

Thats why i just ordered a used ECU from ebay.
The next step is change the ECU to exclude or fix this problem...

[yannickc]

This weekend , the ECU is replaced by a identical second hand one.
My tuner write a copy in this ECU from my car's software and it started and drive straight away.

Its to eary to tell or the problems are fixed.
But i drive more then 300km's this weekend without any problems.

So there is a big change we finally fix the problem.

I will let it know...

[yannickc]

Its been almost a week now sins the swap of my ECU.
I also reconnect the Intake valve back to the ECU for the 2 last days.
And for so far i have tested, not any problem

To celebrate this big break trough, i decide to my both cars (v50 private and v60 company car) a hand wash