BMC CDA Induction Kit, Problem!?

[Roccatmode]

Hi all,

I have an Altea 1.9Tdi 105PD.

As standard all was well...So, I bought myself a BMC CDA induction kit, and fitted it.

I bought a 45 degree silicone elbow, with 5mm self seal take off, for me to attach the crank case breather pipe to. I had the air ducting positioned in my fog light hole so air would be forced in towards to BMC CDA.

I thought all was good, I could hear the turbo spool up nicely as it went in out of the boost range.

But I started noticing something strange. Whilst slowly accelerating through the gears when ever I reached 2,000 rpm or normally just before this, the engine would seem to hesitate. I can't explain it really, but it felt as I reached 2,000 rpm during slow acceleration it would seem as my throttle was being jumpy. This seemed to happen more often after a longer drive, and normally only in second and third gears. However today I noticed it in fourth and fifth whilst accelerating on the motorway and my revs were below 2,000 rpm. However, I don't experience any of this, if I floor it, even from a standing start and the revs are below 2,000 rpm.

It was doing my head in so much that I decided to revert back to the originally filter box set up to see if it was a result of my BMC installation.

After doing so, I test drove it, and for the life of me I couldn't replicate the above. Okay I didn't have a cold air feed to my fog light area making sucking sounds, (which when the BMC was installed would give a audible recognition of the hesitation, like a suck, pause, suck, pause, suck sound even with a constant acceleration) but I didn't even feel any jumpiness or hesitancy from the engine.

I can't understand why the BMC could do this? Is it because it's feeding to much air into the engine and the MAF can't keep up, so in other words my MAF is failing, or does this sound like a dead spot in my rpm range that would be rectified when I get my map done in two weeks.

I don't want to give up on the BMC, it cost a lot, what should I do?


Hope you guys can help.

Thanks

 

[anarchy1515]

I had this exact same problem on my 1.4 tsi it turned out to be the turbo actuator

 

[Roccatmode]

If this was the case wouldn't I experience the same issue both with the BMC and the original air box?

I cannot replicate the problem with the originally air box attached! I'm starting to think that the BMC is more audible and there for gives the impression of hesitation when really there isn't any? Either that or the BMC amplifies the issue which cannot be heard or felt when the original air box is installed.

 

[anarchy1515]

It because the cda is more free flowing so turbo can spool up quicker so you actually feel/hear it with mine I could take the lid off my original air box so you could hear it and its slightly noticeable to feel. With a remap this will highlight the problem so you'll notice it more with stock air filter

 

[Roccatmode]

Regarding the turbo actuator? How did you find out it was this? I mean this short of behaviour can be a symptom of many possible faults, boost leak, misfire, maf sensor, map sensor. How was your problem pinpointed, trail and error?

 

[anarchy1515]

Partly because it's a known issue on my engine and luckily its under warranty but still took 3 weeks in the dealers for them to diagnose but thats mainly because they were trying to get out of it by saying they couldn't notice it. I would have suggested a misfire if yours was a petrol as forced induction can blow out sparks. Its probably worth getting a good garage to check for boost leak first though

 

[Roccatmode]

Only by email mind you, but I spoke with midland VW regarding this issue and this is what they said,

Hi Tim.
Assuming that everything was installed correctly it could be that the intake is allowing more air to the turbo than the ECU is expecting to see and pulling the load back a touch. Difficult to say without seeing it!

Which to me is hopefully the solution, we shall see when I get her mapped on the 1st.

 

[anarchy1515]

Hopefully but if not it'll be seriously noticeable when mapped