293 replies to this topic

[WillC]

On topic. I think it would be best for Moob to plant himself down infront of a PC for some time. Using this time he needs to start drawing his VAC lines out using what ever drawing tool he has in a way he will understand it from the factory manual. That is pretty much what I did for my lines and setup.

 

Without doing at least something like that you will never get anywhere. Grabbing someone elses documents is no good unless they or someone that understands that document that was drawn is there with you showing you the the parts out in your enginebay that you need to be looking at.

 

At least by drawing it yourself and understanding it, you will be able to figure out if something was plugged in wrong or has fallen off.

[Mbooma]

Ok no worries i think my noobness of wanting to fix it.my self hav irritated a few ppl so ill do some more research an if i cant fix.it myself ill just book it into mrt which who the last ones to play around with it and just get it fixed thanks for all the help guys and sorry for being a pain ...

[Dav_fre]

Try to remember we were all noob's at one stage, so don't put too much pressure on yourself to fix it on your own the first time...

Some people here a much more knowledgable than others (most in this thread would know more than me about the TT) and that's the great thing about forums.

I think your on the right track with getting a mechanic to inspect and advise/fix for you this time...

Start with a good working engine and you'll learn much faster.

Best of luck

[Jimbo]

I would also try replacing the entire black box of doom. I'm sure you could find one somewhere. As long as it's the same year model it should go straight in. While, you've done that, clean up your old one and keep it as a spare.

[Dav_fre]

I'm still surprised there are no CEL's

Does the CEL light come on when the key is at 'ON' before you start it ?

Have you plugged in a scanner for previous codes ?

[Tim.]

Perhaps Rob could clarify if the ECV adjustment is a necessary part of the Mod.

Yeah a clarification would be great. Can't assume anything with these TTs.


Yeah good on you for having a go Moob and trying to get this sorted yourself. That's the best way to learn. But there has to be some theory to back up your enthusiasm before you go diving into the TT system. It is finicky and will not cut you any breaks.

[Dav_fre]

It is finicky and will not cut you any breaks.

...and that's why we farken love it..!

That satisfaction of "hell yeah, I just fixed what people that was unbeatable"..!!

[Robbks]

Hi Again..

#1) If you have done the bypass mod, then the adjustment is absolutely necessary. The mod is allowing the exhaust gas pressure from within the exhaust to begin opening the ECV rather than relying on two solenoids, an acytuator and lines with restrictor pills that get blocked and fail

I'd also say it's necessary even without the bypass.

#2) your humming noise on changeover is probably the secondary BPV not closing properly, OR it's the ICV struggling to open
My secondary BPV used to make a vvvooommp noise as it closed. It's the sound of the air rushing past the rubber diaphragm

Have you blocked up or removed (ideally) all the un-needed pipework?
getting rid of it really helps you understand the aiirflowpaths of what's left.

Have you checked and cleaned all the vac lines and solenoids and vents?  if not do not do anything else until you have
Clean and check is ALWAYS step 1.

[Tim.]

I agree, adjusting the ECV is definitely something that should be done regardless of whether you have done the mod or not. You need it to be shut during the primary stage but right on the threshold of opening to help the changeover happen as quickly and smoothly as possible.

[zanzarah]

The ECV will begin to open earlier regardless of adjustment, if the mod ( Line No:5 teed off to Line No:22) is done.

This is due to the programming of the IACV (DPS output voltage is not set to 2.0 when boost would be equal) to open well before the secondary turbo matches primary turbo boost (up to 7 psi). Consequently primary boost backs down through the IACV and into line No:5

[Mbooma]

Ok at this very moment i hav the cooler off an changing the lives should i be able to open an close the evc rod with my hand like a waste gate?
Also i hav all these lines changing over am i best of to do the bypass now or wait to see wat happins
Ok at this very moment i hav the cooler off an changing the lives should i be able to open an close the evc rod with my hand like a waste gate?
Also i hav all these lines changing over am i best of to do the bypass now or wait to see wat happins

[Robbks]

zanzarah:
You're half correct
The point you're missing is that the BPV is still OPEN. It's only got a very weak spring to keep it closed

The pressure's can't equalise until the ECU shuts the BPV, which is at the exact same time as the ECU activates the ECV Negative Pressure Solenoid (Lower Port) to fully open the ECV anyway.

Mbooma:
the ECV is very hard to move, it's a BIG diaphragm.
What you can do to test it is feed the lower port a vacuum supply with the engine running.
Hard to to with the IC off though.

I never needed to remove the IC. just the secondary heat-shield

 

[Tim.]

Rob, wouldn't the BPV open only once the negative pressure is applied to the ECV? Because that's when the preparatory stage begins and the secondary starts to produce boost which is then vented off by the BPV.

The positive pressure side of the ECV is what opens the ECV fully.

Moob: the ECV has a stiff spring to hold it shut. You need to use a spanner to lever the arm of the control valve sticking out of the up pipe to get it to move. I only had to remove the heatshield on the secondary as Rob said, to be able to get to it.

[Robbks]

Sorry, I forgot to add above (now amended)
the BPV has a very light spring to keep it closed under primary operation.
it opens by itself once the secondary starts making boost.

But it's the vacuum port (lower) of the ECV that does the heavy lifting. although the positive pressure port does help to keep it open in case you run out of vacuum pressure if you're on secondary boost for 10 minutes.

the whole entire top-port bypass mod and ECV adjustment, makes the process a mechanical one and not reliant on clogged up solenoids.
It's a bit of a dog chasing it's tail balance.
i.e, yes you do get some pressure acting on the top port, but that's only once the ECV has been opened a little to allow the secondary to turn.
now having that ECV blow open from exhaust pressure is simply less problematic than relying on the "dumb" ECU to cycle two different solenoids
(remembering it's a dumb, open-loop system, the ECU does not take any feedback to monitor the exact timing of the ECV positive pressure operation. it only does what was initially programmed.)


 

[zanzarah]

 VF32-VF31.jpg   23.51KB   1 downloads

 

 

 

The BPV just prior to VOD/Changeover it gets full boost pressure (about 500rpm before VOD) to close .Then at initial VOD it gets a split second shot (0.1sec) of Vacuum (open). Then constant boost through all VOD and TT mode.Essentially the BPV is closed and the IACV open.Primary boost dumping back through the IACV

[Tim.]

But it's the vacuum port (lower) of the ECV that does the heavy lifting. although the positive pressure port does help to keep it open in case you run out of vacuum pressure if you're on secondary boost for 10 minutes.

Got it! I was misled by this article on ClubSub about ECV rod adjustment...

http://www.clubsub.o...50.15/wap2.html

[Jimbo]

Rob, had you ever toyed with the idea of an aftermarket plumb back BOV to replace the stock SBV? I would be interested in seeing differing results with spring tensions etc.