leonardjon Posted September 19, 2009 Share Posted September 19, 2009 Hi people, my first post in this section as its the first issue I've had since owning the car! Basically, its not boosting to 1.2bar as it used to. The first turbo spools up and comes online with no problems that I can tell, but when I get to 4k rpm where the 2nd comes online, I can feel a slight kick but my boost controller is only reporting 0.8 or 0.9bar rather than the 1.2 it used to do quite happily before and its definately not the kick it should be for BPU. I don't notice any smoke or anything from the exhaust when driving and I have looked a couple of times for any split or broken hoses but can't seem to see anything immediately obvious. Turbos don't seem to make any abnormal noises - just the normal whistling and air being drawn in and the BOV seems to be operating normally... Any ideas what could be wrong? Its frustrating! Quote Link to comment Share on other sites More sharing options...
Chris and Alana Posted September 19, 2009 Share Posted September 19, 2009 check the IACV vsv. Take it off the car and and connect 12v to it from the battery and see if the solenoid opens. Sometimes these vsv's can be intermittant. Quote Link to comment Share on other sites More sharing options...
a98pmalcolm Posted September 19, 2009 Share Posted September 19, 2009 i have a simler problem when the car gets warm the boost dies off at 5500 RPM Quote Link to comment Share on other sites More sharing options...
leonardjon Posted September 20, 2009 Author Share Posted September 20, 2009 Thanks for the replys, I have taken a look at the IACV and the arm seems to be moving freely. Will check the VSV - assuming its just a case of disconnecting the two small pipes and the electrical connector to get it off? Quote Link to comment Share on other sites More sharing options...
leonardjon Posted September 20, 2009 Author Share Posted September 20, 2009 (edited) Ok...well have taken the VSV off and connecting it to 12V doesn't really do anything - I can hear a very quiet 'clunk' - what should/shouldn't happen? edit: just done some checks with the multimeter and I think its working as it should be, what is there to try next? Edited September 20, 2009 by leonardjon (see edit history) Quote Link to comment Share on other sites More sharing options...
leonardjon Posted September 20, 2009 Author Share Posted September 20, 2009 Ok, just put the system in parallel mode (sounds quite beefy and smoother!!) but still not boosting over 0.9 bar! Also tried revving the engine from the engine bay to see if the IACV arm moves but couldn't see it moving at any point in the range (I think I went up to around 4k..!) I'm out of ideas now lol Quote Link to comment Share on other sites More sharing options...
Stephendjb Posted September 20, 2009 Share Posted September 20, 2009 Try testing for a boost leak http://www.supraforums.com/forum/showthread.php?t=78644 Quote Link to comment Share on other sites More sharing options...
leonardjon Posted September 24, 2009 Author Share Posted September 24, 2009 Nice link, thanks. Will try that soon hopefully. Mini bump - any other suggestions? Quote Link to comment Share on other sites More sharing options...
leonardjon Posted September 27, 2009 Author Share Posted September 27, 2009 Update: not been able to do a pressure test yet but I have seen the IACV and EGCV arms moving and they seem to be working as they should be. So is that to say I can safely rule out the sequential system side of things? Can hear the exhaust note change and feel a slight power increase when the 2nd turbo comes online and there is still just a minor increase in acceleration. Boost controller is still only showing about 0.8 or 0.9 when 2nd turbo is online Any other possibles? Boost controller solenoid perhaps? Quote Link to comment Share on other sites More sharing options...
Chris and Alana Posted September 28, 2009 Share Posted September 28, 2009 My IACV vsv would work intermittantly, everytime I took it off the car and ran 12v across it it opened fine, but when on the car and moving most the time it wouldnt open (heat effecting it maybe) I changed it and had an instant result and no problem since. I had similar issues as your describing - First turbo boosted fine and when the second was supposed to come on line the boost stayed almost the same or maybe increased by a psi or 2. I would do a pressure test and if that comes back fine and you are still sruggling then try and borrow an IACV vsv from someone and see if it cures the problem. Do you ever see normall boost (1.2bar) now and again or is it always low now? Quote Link to comment Share on other sites More sharing options...
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