Chris and Alana Posted July 10, 2007 Share Posted July 10, 2007 Hi guys, I’ve had an intermitting problem with my car for a little while now and would love to get it sorted. My problem is when I floor the accelerator and it drops down a gear (auto) and the revs are high it should go straight into 1.1ish bar of boost but instead I only get about 3psi and a huge lack in power (this happens maybe 40% of the time) anyway after doing a bit of searching in the past and reading similar discussions I decided to replace as many hoses as I could get to incase of a split hose but that didn’t solve it. I then found Ian's guide http://www.mkivsupra.net/vbb/showthread.php?t=35926 and it loo’s like it could very well be problem 2:- Problem 2: I don't get a 2nd turbo rush, and as soon as I should it dumps all boost instead. The IACV is opening but the second turbo isn't spinning. All the air boosted by #1 turbo now has an easy path back to the non-pressurised side of the turbo’s via a non-spinning #2 turbo. In effect, it all goes 'backwards' through #2 instead of going into the engine. You'll maybe see .2 or .3 of a bar of boost but that's about it. This usually means the EGCV isn't opening. The turbo can't spin as it has no exhaust gas flow path. Although annoying, this won't do long-term damage as #1 turbo won't generate much boost because the engine loses a lot of power, so no overspeeding or overheating. Now if this is the case, I think the next step would be to change the EGCV vsv but from the pics I just cant make out what it looks like or where it is located. Iv had a look at my car but there are quite a few components that look alike down in that area. Does anyone have a pic of the EGCV by itself or still attached. Could my problem be something else? I would really like to get this problem sorted as its quite annoying especially when you go to overtake on a carriage way and left with no power. I would like to see if I can do it myself before spending a fortune paying a garage to do all the work so any advice would be great. Thanks guys. Quote Link to comment Share on other sites More sharing options...
Tricky-Ricky Posted July 10, 2007 Share Posted July 10, 2007 Have you tried the quick TTC mod to see if that eliminates the problem? Quote Link to comment Share on other sites More sharing options...
Ian C Posted July 10, 2007 Share Posted July 10, 2007 The EGCV can be seen here: http://www.mkivsupra.net/vbb/attachment.php?attachmentid=13944&d=1112559002 The VSV is: http://www.mkivsupra.net/vbb/attachment.php?attachmentid=13938&d=1112558977 bottom left blue connector under the word "actuator", sorry it's not marked. -Ian Quote Link to comment Share on other sites More sharing options...
Tricky-Ricky Posted July 10, 2007 Share Posted July 10, 2007 Looked everywhere for those pics, doh! Quote Link to comment Share on other sites More sharing options...
Chris and Alana Posted July 10, 2007 Author Share Posted July 10, 2007 Right guys, I found a way to test the vsv's with a meter from this web site http://www.max-boost.co.uk/max-boost/supra/turbo.htm (its at the bottom of the page) and Iv tested the IACV vsv, the EGBV vsv, the EGCV vsv which all seem to be fine. However, when I tested the wastegate vsv it had a resistance of 2.2mega ohms between the two points (+ and -) and it should be between 22 - 26 ohms so a big problem there. Also when you run 12v across the + and - the vsv doesn’t open so I think its safe to say its broke. Now what I don’t understand is how the boost doesn’t go through the roof if the wastegate vsv is broke because surely the wastegate cannot open. . . . Just to clarify, the wastegate vsv is the larger dark blue coloured vsv and the EGCV is the smaller black one right. If Im right with my diagnosis then could a broken wastegate vsv cause the problem Im getting? I Also tested the pressure vessel which is fine and the IACV actuator is working fine as well. Quote Link to comment Share on other sites More sharing options...
Tricky-Ricky Posted July 10, 2007 Share Posted July 10, 2007 The wastegate will still open due to it still receiving a pressure signal from the turbo via the other tube;). Quote Link to comment Share on other sites More sharing options...
Chris and Alana Posted July 10, 2007 Author Share Posted July 10, 2007 What other tube? (it would explain why my boost never goes too high) Will it do any damage driving it like with a broken wastegate vsv? and does anyone know what symptoms I should have with this fault? I know whats actually wrong with the car, lack of boost sometimes etc, I also sometimes get a low bad idle, could this be related? I thought I would ask to see if this is the cause of my problems. I think Il have to find a working vsv and swap it over and see what happens. Thanks for the help guys. Quote Link to comment Share on other sites More sharing options...
Tricky-Ricky Posted July 10, 2007 Share Posted July 10, 2007 There two feeds to the waste gate actuator, one is a reference feed from the turbo housing and the other i to/from the VSV. Quote Link to comment Share on other sites More sharing options...
Chris and Alana Posted July 10, 2007 Author Share Posted July 10, 2007 Ah, thank you. So the waste gate will still open which is why I still have steady boost when it works. So what does the wastegate vsv control and do? Is it simpley the wastegate actuator which opens the wastegate? if so why is it needed if it will open anyway from a different feed? Also, do you guys think that this could be the cause of my problems? From all the checks iv done it seems to be the only thing broke. Quote Link to comment Share on other sites More sharing options...
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