Samurai 20V Posted February 26, 2015 Share Posted February 26, 2015 (edited) Hi chaps.. I recently solved an erratic boost problem on my car with replacing the IACV VSV and the vac hoses connected to it.. I have picked up another issue, seems a big one, but erratic in nature. Basically I take off, floor the car, no boost, get like 0.3bar max sometimes, no 2nd turbo online, doesn't seem to matter what gear.. When I do get boost, I get about 0,5 bar on the 1st turbo, 0.95 bar on the 2nd.. Car feels sluggish in this time. I did manage to get 1.2 bar whilst testing for a short while, then went back to the erratic behavior.. From reading Ian C FAQ, I think that the IACV is getting stuck, I need someone to concurr I am on the right path before buying any new parts.. Thanks in advance.. Edited February 27, 2015 by Samurai 20V (see edit history) Quote Link to comment Share on other sites More sharing options...
Mk4Gaz Posted February 26, 2015 Share Posted February 26, 2015 From the symptoms you're describing, it sounds like a faulty iacv vsv Have you tested it, with a multimeter? The instructions are in the bgb, and is dead easy to do Quote Link to comment Share on other sites More sharing options...
Samurai 20V Posted February 27, 2015 Author Share Posted February 27, 2015 From the symptoms you're describing, it sounds like a faulty iacv vsv Have you tested it, with a multimeter? The instructions are in the bgb, and is dead easy to do I just replaced it with a brand new one a few weeks ago, haven't tested it.. Will do the test on this valve, I have another new one for my friend, will use that to test before ordering anything else.. Quote Link to comment Share on other sites More sharing options...
Samurai 20V Posted February 27, 2015 Author Share Posted February 27, 2015 (edited) Ok, So tested the IACV vsv, it passed continuity, but not much air coming out of the filter compared to the new one.. I then put the car into TTC mode, got over 1 bar boost, both turbo's are working (exhaust note is awesome!) Then back out of TTC, fitted the new IACV VSV, car is making 1bar in 2nd gear, 1.1 bar in 3rd gear and 1.12bar in 4th.. There are still some remaining issues.. 1. The transition point seems slightly delayed 2. The car was boosting about 0.1bar higher with the same EBC settings when I fitted the 1st new valve. I tried upping the gain on the EBC, it didn't boost any higher, seems it got worse.. When I fitted the first valve, the settings were all too high, the car was overboosting, seems as though something else is wrong as the boost is not rising when adjusting the gain. 3. If i floor it in 1st gear, the 2nd turbo does not come online, it just sits at 0.3bar...When I change to 2nd, it boosts normally.. It still feels savage, when it boosts to that 1.1bar.. I think after reading the FAQ, I have a slow IACV and EGCV VSV.. Can anyone help on the issues remaining? Thanks. Edited February 27, 2015 by Samurai 20V (see edit history) Quote Link to comment Share on other sites More sharing options...
Scott Posted February 27, 2015 Share Posted February 27, 2015 Sounds like the other valves are faulty, at least one. It's been a while since I did any fault finding with the sequential system, but I would put a wanted ad up for a full set of 2nd hand valves. They are fairly reliable and cheap to buy 2nd hand. That way, if you really want new you can find which one is faulty with a cheap set. Quote Link to comment Share on other sites More sharing options...
Samurai 20V Posted February 27, 2015 Author Share Posted February 27, 2015 Sounds like the other valves are faulty, at least one. It's been a while since I did any fault finding with the sequential system, but I would put a wanted ad up for a full set of 2nd hand valves. They are fairly reliable and cheap to buy 2nd hand. That way, if you really want new you can find which one is faulty with a cheap set. Thanks Scott... I found a set of piping and VSV's in Japan with 10000kms on them from an Aristo.. Negotiation with a friend to send them down asap.. In the meantime, going to run the car in TTC for the wonderful tone and to avoid damaging the new IACV VSV.. Quote Link to comment Share on other sites More sharing options...
Scott Posted February 27, 2015 Share Posted February 27, 2015 Sounds like a plan Quote Link to comment Share on other sites More sharing options...
Samurai 20V Posted February 28, 2015 Author Share Posted February 28, 2015 Spent the morning driving the car in TTC mode.. Exhaust note is wild.... Car hits 1.2 bar every time, making me think whether I should bother going back to sequential mode... Quote Link to comment Share on other sites More sharing options...
Scott Posted February 28, 2015 Share Posted February 28, 2015 If you're happy with the way the power is delivered and enjoy the note then I would definitely make it permanent. If you want to get the best out of it a piggyback ECU is a must. If you're thinking about a single turbo anytime in the future then just going straight to stand alone would be my choice. Quote Link to comment Share on other sites More sharing options...
Samurai 20V Posted March 1, 2015 Author Share Posted March 1, 2015 (edited) If you're happy with the way the power is delivered and enjoy the note then I would definitely make it permanent. If you want to get the best out of it a piggyback ECU is a must. If you're thinking about a single turbo anytime in the future then just going straight to stand alone would be my choice. I have been planning a piggyback ECU, these boost issues have delaying the fitment... Still deciding on the single turbo... Edited March 1, 2015 by Samurai 20V (see edit history) Quote Link to comment Share on other sites More sharing options...
mellonman Posted March 1, 2015 Share Posted March 1, 2015 When you have been out and got full boost in TTC, go home wait 10 minutes and pull the vac pipes off the iacv vsv if it releases the air preasure . If it does let off a woosh of air all should be good but if it doesnt you have a leak somewhere, normall when number 2 comes on late its the iacv vsv which is odd as its new. If you go out in TTC and you get full boost after a couple of close boost blasts then after pottering around for a while then dont quite make full boost straight away, this would also indicate a leak in the pressure line / tank I would double check vac lines including the ones on the intake side Quote Link to comment Share on other sites More sharing options...
Samurai 20V Posted March 1, 2015 Author Share Posted March 1, 2015 When you have been out and got full boost in TTC, go home wait 10 minutes and pull the vac pipes off the iacv vsv if it releases the air preasure . If it does let off a woosh of air all should be good but if it doesnt you have a leak somewhere, normall when number 2 comes on late its the iacv vsv which is odd as its new. If you go out in TTC and you get full boost after a couple of close boost blasts then after pottering around for a while then dont quite make full boost straight away, this would also indicate a leak in the pressure line / tank I would double check vac lines including the ones on the intake side I did the test you described when I first had the problem, there was whoosh of air let off.. TTC is making full boost all the time, seems as though there are no leaks.. But you are right, will double check everything, I have a good condition set of VSV's on the way from Japan, with the intake piping etc, gonna refurb as much as possible.. Quote Link to comment Share on other sites More sharing options...
Mk4Gaz Posted March 1, 2015 Share Posted March 1, 2015 Glad you're half way to sorting it bud, I have to admit, I did enjoy ttc in mine! Quote Link to comment Share on other sites More sharing options...
mellonman Posted March 1, 2015 Share Posted March 1, 2015 Arh then it proberly is a vsv of some sort do you have a boost controller ? When these are fitted you bypass some of the vsv which would then take away some of the points to check Quote Link to comment Share on other sites More sharing options...
Samurai 20V Posted March 1, 2015 Author Share Posted March 1, 2015 Glad you're half way to sorting it bud, I have to admit, I did enjoy ttc in mine! Thanks mate.. Appreciate the help... TTC is entertaining.. Arh then it proberly is a vsv of some sort do you have a boost controller ? When these are fitted you bypass some of the vsv which would then take away some of the points to check I have an HKS EVC.. I also think its a VSV. I only have the EGCV and EGBV operational after fittting the boost controller, will troubleshoot when I get the replacement ones.. Thanks for the help.. Quote Link to comment Share on other sites More sharing options...
Scott Posted March 1, 2015 Share Posted March 1, 2015 EGCV is the likely suspect for late 2nd turbo IIRC. Quote Link to comment Share on other sites More sharing options...
Samurai 20V Posted March 1, 2015 Author Share Posted March 1, 2015 EGCV is the likely suspect for late 2nd turbo IIRC. You mean the associated VSV Scott? Quote Link to comment Share on other sites More sharing options...
Scott Posted March 1, 2015 Share Posted March 1, 2015 You mean the associated VSV Scott? Sorry mate, yes. The EGCV VSV The valve itself can sometimes be faulty though. I had mine stuck open once. If the valve itself is sticky then it can lead to intermittent turbo 2. Mine was completely stuck open so I ended up with no turbo 2 lol. Quote Link to comment Share on other sites More sharing options...
Samurai 20V Posted March 1, 2015 Author Share Posted March 1, 2015 Sorry mate, yes. The EGCV VSV The valve itself can sometimes be faulty though. I had mine stuck open once. If the valve itself is sticky then it can lead to intermittent turbo 2. Mine was completely stuck open so I ended up with no turbo 2 lol. Thanks mate.. Appreciate the help... I will change those VSV's first thing.. I think I had enough of TTC though, car is way too loud.. Quote Link to comment Share on other sites More sharing options...
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