Durandal Posted June 30, 2018 Share Posted June 30, 2018 So after searching I have found that several people have had the same issue I seem to be having. Boosts fine if you WOT in first or second and shift through gears but down shifting or very gradual ramp up of RPM yields low boost to around 0.4 bar then drops off at around 3800 RPM when the sequential stuff kicks in. I tested the IC piping with a can of spaghetti and ended up launching it across the garage. I've read through Ian C troubleshooting post and some others who have found split hoses. I bought a pressure/vacuum tester and manually tested all my actuators which seem to be working and used an ohm meter and 12 v supply on the VSV they all check out fine as well. So I put the car in TTC temporarily and it boosts great all the time when it is supposed to. The next day I checked and the EGCV and IACV actuators are still wide open so my pressure tank should be in good working order as well. Today I disconnected the hose marked with the pink arrow and used my hand pressure pump to build up to 1.1 bar. The EGBV opened and it very slowly dropped off to 0 bar (10 minutes or so). Felt around all the hoses fed from there and could not feel or hear any air leaking. Is that normal? Quote Link to comment Share on other sites More sharing options...
Durandal Posted June 30, 2018 Author Share Posted June 30, 2018 Update re-checked some things again and it seems the IACV VSV is intermittently reading open so looks like a bad coil. So will need to order one of those and see if it fixes the problem. While testing EGCV VSV i also noticed the WG VSV is also bad although I am using a boost controller solenoid so that is not being used anyway. Quote Link to comment Share on other sites More sharing options...
Durandal Posted July 1, 2018 Author Share Posted July 1, 2018 I had read that the IACV and EGCV open at around 0.5. I tested mine and they start to open at around 0.3 bar. Or was the 0.5 the pressure at which they are fully open? Quote Link to comment Share on other sites More sharing options...
Mike2JZ Posted July 1, 2018 Share Posted July 1, 2018 Not sure about what pressures they are fully open, but had a TT with similar symptomes due to IACV VSV being broken Quote Link to comment Share on other sites More sharing options...
Durandal Posted July 1, 2018 Author Share Posted July 1, 2018 Yah I am hoping that is the cause. Waiting for a quote on a replacement. Might order the EGCV VSV as well. Quote Link to comment Share on other sites More sharing options...
Durandal Posted July 2, 2018 Author Share Posted July 2, 2018 (edited) While waiting for VSV to arrive I figured I'd check some other things No1 turbo pipe quite choked off. Probably why the No1 turbo always made a higher pitched noise. Do people bother replacing these with stock ones again or get a different style pipe coupling? I can probably get a some 2 inch hydraulic hose which I'm sure would hold up in the vacuum environment. Edited July 2, 2018 by Durandal (see edit history) Quote Link to comment Share on other sites More sharing options...
Durandal Posted July 22, 2018 Author Share Posted July 22, 2018 Just updating this in case someone stumbles across similar issues with the search function. After installing new inlet link pipes to the turbos and a new IACV VSV, the car seems to be working properly in sequential mode now. On down shifts both turbos kick in. Quote Link to comment Share on other sites More sharing options...
SupraTRD_MK4 Posted July 30, 2018 Share Posted July 30, 2018 Nice to know and thanks for updating the post mate. Will be helpful for alot of us who retain the std twin turbo setup Quote Link to comment Share on other sites More sharing options...
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