Chris and Alana Posted October 1, 2008 Share Posted October 1, 2008 Hi guy's and girls, I have done a quick search but not found the answer to my problem (however I will continue to search ) but for now if anyone could help it would be appreciated. The car - first de-cat, FCD, Blitz boost controller, cat back exhaust, other supporting BPU mods. Right, I seem to have developed an issue with boost in the last 2-3days which is quite annoying. When I put my foot down the first turbo produces around 9-10psi (which is normal) and when it reaches 3500-4000 I can hear the exhaust note change as usual but the boost reads 11ish psi on the gauge and 0.78bar on the boost controller which is about stock levels, however I have been running 1.1ish bar for over a year now This fault is intermittent as sometimes it will still produce 1.1bar but most the time it wont (this is with the boost controller turned off) I did turn the boost controller up to see what would happen and the boost did increase slightly but way off what it should be. Could this be a boost leak? If it was why would the first turbo be unaffected? Quote Link to comment Share on other sites More sharing options...
RobSheffield Posted October 1, 2008 Share Posted October 1, 2008 Tried this http://www.mkivsupra.net/vbb/showthread.php?t=35926 ? Quote Link to comment Share on other sites More sharing options...
suprattgaz Posted October 1, 2008 Share Posted October 1, 2008 If boost controller turned off, what is controlling the wastegate and hence pressure?? The boost controller (Blitz) leaks air to atmosphere fooling the ECU to up the boost, so with it off you have lost that control. I would check all hoses to actuators, and solenoid to Boost controller. Also pressure feed pipes going to boost gauge and boost controller. I might be wrong but that is where I would start. If you were closer i would come help. Quote Link to comment Share on other sites More sharing options...
Homer Posted October 1, 2008 Share Posted October 1, 2008 Is this only happening intermittantly on a drive, i.e. when it's been cruising for a bit then you put your foot down and go though the switch-over point to the 2nd turbo? If so, what happens if you lift of for a moment, then re-apply the throttle - does it come back up to high boost again? Quote Link to comment Share on other sites More sharing options...
Chris and Alana Posted October 2, 2008 Author Share Posted October 2, 2008 Tried this http://www.mkivsupra.net/vbb/showthread.php?t=35926 ? Thanks for that I forgot about that thread. If boost controller turned off, what is controlling the wastegate and hence pressure?? The boost controller (Blitz) leaks air to atmosphere fooling the ECU to up the boost, so with it off you have lost that control. I would check all hoses to actuators, and solenoid to Boost controller. Also pressure feed pipes going to boost gauge and boost controller. I might be wrong but that is where I would start. If you were closer i would come help. I thought the EBC when turned off left the airways open through the solenoid allowing the wastegate to open and keeping boost to standard pressure (or what ever the RR allows to happen) and when turned on does what you have explained to increase boost. The solenoid on the EBC I have takes the place of the standard Wastegate vsv. Thanks for offering your help though, appriciated (even though your many moons away) Is this only happening intermittantly on a drive, i.e. when it's been cruising for a bit then you put your foot down and go though the switch-over point to the 2nd turbo? If so, what happens if you lift of for a moment, then re-apply the throttle - does it come back up to high boost again? No, it just happens randomly, I did have a problem over a year ago with boost doing what you have suggested and it turned out my wastegate vsv was bust. Once replaced it worked fine until now but this problem has different symptoms. It seems very similar if not exactly the same to 'problem 1' in Ians guide (link in second post) I have checked the hoses to and from the IACV vsv but they are fine. I will remove the vsv as soon as I can (tonight hopefully) and run 12v across it to see if it opens, hopefully it wont Does anyone know if you can check to see if the IACV actuator is working? If so what test's can be done? Thanks for the help so far guy's. Quote Link to comment Share on other sites More sharing options...
AndyT Posted October 2, 2008 Share Posted October 2, 2008 http://www.max-boost.co.uk/max-boost/supra/turbo.htm Should help you bud. IACV_tests.pdf Quote Link to comment Share on other sites More sharing options...
hodge Posted October 2, 2008 Share Posted October 2, 2008 p.m'ed. Quote Link to comment Share on other sites More sharing options...
Chris and Alana Posted October 2, 2008 Author Share Posted October 2, 2008 Right, Iv had the IACV vsv off and done the checks that Andy T has put up. All the checks were fine except when I first took it off (it was quite hot) the resistance read 1.126mega ohms which is alot but when it had cooled it read 48ish ohms (more normal) I measured it quite alot of times and as is it was cooling it started reading in the kilo ohms until it finally read normal. Could it be possible that something in the vsv has spat the dummy and when it gets hot (engine bay temps?) that it stops working? While I was under the bonnet I tested the Actuator that is connected to the IACV by attatching a foot pump and gently adding pressure, it opened and closed smoothly every time so I think this is fine. I also tested the EGBV vsv (as it was easy to remove) and this also seemed fine. It opened when I added 12v across it but I forgot to take a resistance reading. Once I had put everything back together I took a trip to my parents house (approx 2miles away) and opened her up 2-3 times and everything worked fine. there was a slight pause at 3500-4000rpm and then the second turbo came online and it produced 1.1ish bar, happy days. Now on my way home after a 10min stop at my parents I opened her up again and the problem was back, it boosted to approx 10psi on first turbo, there seemed to be a pause at 3500-4000rpm and then when I should get 1.1bar it stayed on 10-11psi. I tried taking my foot off the accelerator and re-applying several times but it made no difference, it stayed at 10-11psi This is annoying now and I am a little bothered about trying the right foot after fiddling with something incase I blow No.1 tubbie (as in Ian's thread-problem 1) I dont think this is related to the pressure tank as when I released one of the hoses on the IACV vsv it released a load of pressure so I figured the hoses between the tank and the actuator must be intact. I am now stuck in which direction to go in. The only things I didnt check were the EGCV and actuator as they were a little harder to get too and daylight was dissapearing. Also from Ians thread if these were playing up the car would have completely different symptoms. Quote Link to comment Share on other sites More sharing options...
suprattgaz Posted October 2, 2008 Share Posted October 2, 2008 See this.... http://www.mkivsupra.net/vbb/showthread.php?t=158451&highlight=loss+boost+car+warms It sounds like you have exactly the same symptoms as what I had (except the faint whistling/leak noise). I'm afraid I went TTC and the problem disappeared, but never found the root cause. I think it was VSV or pressure tank related, both now are eliminated due to TTC. (or I could be many moons away!) Quote Link to comment Share on other sites More sharing options...
Chris and Alana Posted October 2, 2008 Author Share Posted October 2, 2008 I think it was VSV or pressure tank related, both now are eliminated due to TTC. (or I could be many moons away!) I didnt mean anything bad by this lol, I just ment that you live very far from me but I appriciated the offer. (sorry if I looked like something else ) Quote Link to comment Share on other sites More sharing options...
Chris and Alana Posted October 2, 2008 Author Share Posted October 2, 2008 oh, how do I make sure that the pressure tank is opperating correctly so I can eliminate this? Quote Link to comment Share on other sites More sharing options...
suprattgaz Posted October 3, 2008 Share Posted October 3, 2008 I didnt mean anything bad by this lol, I just ment that you live very far from me but I appriciated the offer. (sorry if I looked like something else ) LOL! How funny - show's how txt can be taken so wrong doesn't it! Quote Link to comment Share on other sites More sharing options...
michel lane Posted October 3, 2008 Share Posted October 3, 2008 sounds like a faulty turbo actuator on the second unit . To repair this , means turbo off time . Quote Link to comment Share on other sites More sharing options...
Chris and Alana Posted October 3, 2008 Author Share Posted October 3, 2008 (edited) sounds like a faulty turbo actuator on the second unit . To repair this , means turbo off time . Is that the actuator that is connected to the EGCV vsv, kind of underneath the turbos? If so, I am going to test this with a foot pump to see if it moves with pressure (under 7psi I believe is about right but correct me if I am wrong) Is there a third actuator? I know it might be a little hard to say but someone with more knowledge than me might be able to answer - will any harm be done if I put my foot down with this problem? I kind of need to to test if it is working or not after I have done things (poked about with a stick ect) but dont want to blow the tubbies in the proces. Edited October 3, 2008 by Chris and Alana (see edit history) Quote Link to comment Share on other sites More sharing options...
Chris and Alana Posted October 5, 2008 Author Share Posted October 5, 2008 Just to add, I had a trip up to scotland this weekend 180miles both ways, I was trying to keep off the accelerator but over 180miles it was pretty difficult Now on the way up the car seemed to boost correctly which was good but I only floored it several times. Now on the way back I decided to try it a little more and for the first 130miles or so it would only boost to 10psi, now I tried to listen to the exhaust note changing at 4000rpm and did seem to change slightly louder and deeper but the boost gauge would still read 10psi I then got stuck behind traffic for 5miles or so and when the dual carridge way came I put my foot down and I had boost back, 1.1bar and it stayed like that the rest of the way home. Now even though I had full boost the felt a little slugish and Im sure I could here a hissing noise with the window down. Could this simply be a split in a hose, I have checked all of the vacuum hoses except the ones behind the engine because I cant reach them but I am yet to check all the actuator and the intercooler plumbing. This is doing my head in it seems to be one problem after another. Iv just spent over £1k fixing the suspension last month and now this, I just want to enjoy the bloody car before the winter. Quote Link to comment Share on other sites More sharing options...
hodge Posted October 6, 2008 Share Posted October 6, 2008 I still think it's an air leak mate. Check the 2 vac lines that go to the vsv infront of the of exhaust gas bypass valve. Is 1of these are damaged/slit the valve won't open hence reduce boost. If it's a small split then the effects could be intermitent. I could be totally off here mate but I'd does seem like an air leak issue but like I said I could be wrong. Quote Link to comment Share on other sites More sharing options...
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