Sequential issues. Vsv problem?

[jaymdee]

Have searched on all sorts and read all the guides to the sequential system but still can't quite fathom my problem.

 

Haven't been using the car much the last 2 years due to work requiring a company car and it's developed an intermittent problem with losing boost when T2 should come on line. Logic says this is the EGCV or the VSV. Yesterday I went out and whilst it was still doing this, sometimes it worked fine and sometimes needed to lift off and then plant right foot again and it would work.

 

But I then noticed that if this still didn't work, when I then went to boost, T1 was struggling.

 

My thought is I have 2 issues

 

1. Problem with EGCV preventing T2 working and the boost from T1 disappearing

2. Problem with the IACV staying open and thus T1 not being able to produce boost as the air is travelling through a non spinning T2.

 

Have done the temporary TTC mod and after pressurising the system I was getting boost from around 3k and full 1 bar at 4k.

 

After reading loads of posts and guides I'm looking to test the vsv's but don't quite understand what I've read to do this. How do I power the vsv to see if it opens?

 

Any help or advice greatly received:-)

 

Cheers

[fastcar]

Take the vsv off and give them a good soak with WD40 over night and then reinstall!! Should sort the problem out as they tend to get a little sticky when not used much. Happend to mine and now all sorted:cool:

[jaymdee]

Take the vsv off and give them a good soak with WD40 over night and then reinstall!! Should sort the problem out as they tend to get a little sticky when not used much. Happend to mine and now all sorted:cool:

 

Good idea, but just snapped a bloody nipples off the iacv vsv. Bastard. Also just been out and 2 hours after driving in ttc mode the iacv and egcv actuators are not pressurised. How long should the system hold pressure in ttc? When I stopped on a run and checked they were both at full extension.

[Fitz]

...it's developed an intermittent problem with losing boost when T2 should come on line. Logic says this is the EGCV or the VSV. Yesterday I went out and whilst it was still doing this, sometimes it worked fine and sometimes needed to lift off and then plant right foot again and it would work.

 

Same problem mine has, tends to happen from higher speeds/cruising then trying to gun it.

[Shane]

I had identical symptoms recently and mine turned out to be the EGCV VSV. Mine seemed to work fine out of the car and on the bench and was cleaned etc. I used one I had laying around from a NA in the end cable tied to the original as although the same in terms of connections and ports, the mounting is different, but covered quite a few miles now and its been good. Josh has one for sale, might get you out of trouble until you find a TT one.

 

http://www.mkivsupra.net/vbb/showthread.php?328328-NA-(2JZ-GE)parts-clear-out&highlight=jOSH

 

I used the brown/red one that is normally attached to the vacuum canister on a NA.

Edited May 16, 2016 by Shane (see edit history)

[T2 MSW]

If you need a VSV I have a set for sale in the for sale section

[jaymdee]

Update. Have fitted new iacv and egcv vsv's and replaced the associated 4mm hoses with new reinforced gates style rubber tubing.

 

Whilst better, it's still not operating correctly. Next to replace all the hoses. Hoping it's not pressure tank failed. I removed the vacuum pipe to the iacv vsv 10 mins after stopping and got a woosh of air so the system is holding pressure.

[Sandesupra]

Jack up the car and check the two vacuum lines from the pressure tank..

 

Also the lines going to the vsv's

 

PT fail is not common.. quite rare..

 

check if the actuators (iacv and egcv) are working properly.. should open at about 7psi.. you can find this in the tsrm:-)

 

happy hunting!:-) been there...

Edited May 24, 2016 by Sandesupra (see edit history)

[jaymdee]

Cheers. Have tested operation of the iacv and egcv actuators today revving from inside the engine bay. Both operate but are a bit slow to respond. I wonder if they are a bit 'sticky' leading to one opening before the other and me losing boost on kickdown and then the iacv staying open longer meaning iv i boot it again T1 boost is disappearing down T2 intake momentarily.

 

From low revs T1 builds boost to 0.7bar and then you get the transition and then 1.1 bar. It's on kickdown I have the issue...

 

Think I can hear a bit of a boost leak too so def need to replace all the hoses.

[KKMMK2N]

I too feel your pain - I am just coming to the end of a very similar issue. I replaced all the hoses, vsv's and ended up getting both turbos rebuilt before finally figuring out that the issue was with the reed valve inside the IACV. When I opened the four screws on top of the IACV and pulled out the reed valve, both the reeds were sagging down slightly (only about 3-5mm) leaving a gap thus screwing the transition. If replacing the hoses and double checking the IACV VSV doesn't fix it, check to see if your reed valve is bent.