DJT88 Posted May 11, 2013 Share Posted May 11, 2013 Hi all, I've been trying to find a cure for a boost problem(car holding back above certain boost level). Hopefully fix it before Dragonball I don't really recognize my problem in any FAQ's or Searches I've done. problem: Whenever I press the accelerator, after the initial boost-kick, then whenever the boost rises above (>0.5) bar the car holds back. If I then feather the throttle at a certain level I can maintain boost ~0.5 and the car pulls ok. And switches to parallel mode fine. However I can't let it boost higher or it will hold back on me. (doesn't feel like misfire, and no fault codes ). car specifications(J-spec TT): - Electronic boost controller (greddy profec-b) - fcon-s piggyback last changes - changed exhaust to catback (first cat remaining) - CW SMIC 1. Could these recent changes messed up tuning? (SMIC and Catback) problem didn't start then. 2. Can I safely try disconnecting the FCON piggyback and just try with the stock ECU? 3. Does anyone know what's going on here? HELP Quote Link to comment Share on other sites More sharing options...
mellonman Posted May 11, 2013 Share Posted May 11, 2013 Sounds like the 2nd turbo isnt kicking in have you tried letting off and then flooring it could be a sticky vsv, check the technical guide for sequnsial system Quote Link to comment Share on other sites More sharing options...
DJT88 Posted May 11, 2013 Author Share Posted May 11, 2013 (edited) Letting off and flooring it doesn't make a difference... It's like someone is slowly applying the brake whenever I press the accelerator too much(more if I floor it). But could it hurt to unplug the piggyback and plug the OEM ECU straight back? I want to exclude a mapping problem. edit: If I floor it, it doesn't want to clime past 4000 rpm, but if I hold back a little I can get it to 6000 no prob. (just with lower boost) Edited May 11, 2013 by DJT88 (see edit history) Quote Link to comment Share on other sites More sharing options...
JasonR24 Posted May 11, 2013 Share Posted May 11, 2013 I had an issue like this in an old turbo car i had and it was because the engine couldn't get enough fuel. When I floored it, it literally got to a point and felt like it was engine braking. Try fuel filter as its a cheap easy fix. If its not that then try the FAQ on the sequential system. Vsv seems common Quote Link to comment Share on other sites More sharing options...
DJT88 Posted May 11, 2013 Author Share Posted May 11, 2013 I had an issue like this in an old turbo car i had and it was because the engine couldn't get enough fuel. When I floored it, it literally got to a point and felt like it was engine braking. Try fuel filter as its a cheap easy fix. If its not that then try the FAQ on the sequential system. Vsv seems common Will try fuel filter. Does make sense, and is indeed easy to try, just have to order it ASAP. Can anyone confirm my other question? Can I try without piggyback? Could it hurt? Last thing I want to do now is wreck something before DB. Quote Link to comment Share on other sites More sharing options...
Ian C Posted May 11, 2013 Share Posted May 11, 2013 If you've got stock injectors and turbos I can't see why you've even got a piggyback ECU in there in the first place, so removing it should be okay as a test. But here's what I think based on what you've said so far: The second turbo isn't coming online. You mention 4000rpm, this is exactly when it should come on, so that makes this quite likely. The first turbo gets overspeeded if #2 doesn't come on as it gets too much exhaust gas. It can only cough up about 0.5bar of boost (another symptom tick) and it causes detonation as the intake charge by now gets heated up massively - so the ECU will pull ignition timing as well. Feathering the throttle will lower the exhaust gas going through the turbo and reduce it to sensible rotational speeds, so it'll feel "better" as timing isn't being pulled and you'll actually get more power out of it. I've seen this happen, and in fact datalogged it, during a mapping session years ago with Soop Dogg's car back then, so this is from experience. Check the Intake Air Control Valve is opening up. Also, wire it up into parallel mode to test full boost with the sequential system out of the loop - if it still does it, chances are it's not that. Quote Link to comment Share on other sites More sharing options...
DJT88 Posted May 12, 2013 Author Share Posted May 12, 2013 If you've got stock injectors and turbos I can't see why you've even got a piggyback ECU in there in the first place, so removing it should be okay as a test. But here's what I think based on what you've said so far: The second turbo isn't coming online. You mention 4000rpm, this is exactly when it should come on, so that makes this quite likely. The first turbo gets overspeeded if #2 doesn't come on as it gets too much exhaust gas. It can only cough up about 0.5bar of boost (another symptom tick) and it causes detonation as the intake charge by now gets heated up massively - so the ECU will pull ignition timing as well. Feathering the throttle will lower the exhaust gas going through the turbo and reduce it to sensible rotational speeds, so it'll feel "better" as timing isn't being pulled and you'll actually get more power out of it. I've seen this happen, and in fact datalogged it, during a mapping session years ago with Soop Dogg's car back then, so this is from experience. Check the Intake Air Control Valve is opening up. Also, wire it up into parallel mode to test full boost with the sequential system out of the loop - if it still does it, chances are it's not that. Ian, Thanks! Will try to check these things. TTC will be good to rule some things out. The piggyback was already installed when I bought the car, but yeah doesn't make sense for the few mods it has. Quote Link to comment Share on other sites More sharing options...
DJT88 Posted May 12, 2013 Author Share Posted May 12, 2013 I have just found out that there are some strange things with my setup. My IACV VSV didn't have the boost line attached to it. It was already capped off. (due to the nipple being broken off, and repaired by someone not willing to pay for a new one.) Don't know how it could have worked before :S Also, my VSV for the EBV doesn't have the plug connected but is tie-wrapped out of the way. This is how it was on the car: Broken off like this: Ordering new one tomorrow. Quote Link to comment Share on other sites More sharing options...
mellonman Posted May 12, 2013 Share Posted May 12, 2013 I would check how your boost controler is set up firstvas some of the vsv are bye passed when fitting one, they are alot of money mate new try ttc first or plub it all back to stock and go for a spin Quote Link to comment Share on other sites More sharing options...
mellonman Posted May 12, 2013 Share Posted May 12, 2013 You have looked here right Quote Link to comment Share on other sites More sharing options...
DJT88 Posted May 12, 2013 Author Share Posted May 12, 2013 Yes, but it didn't really feel like any of those problems. But Ian's explanation made sense(ecu retarding timing etc.) I'm busy trying to map how the EBC is plumbed in now. Will update with a schematic once I've figured it out. Quote Link to comment Share on other sites More sharing options...
DJT88 Posted May 12, 2013 Author Share Posted May 12, 2013 (edited) Looks like this is how my EBC is plumbed in. edit: updated picture, ecb also connected to EGBV #2 turbo. new picture again(Waste Gate vsv also no connector): Edited May 12, 2013 by DJT88 (see edit history) Quote Link to comment Share on other sites More sharing options...
DJT88 Posted May 12, 2013 Author Share Posted May 12, 2013 Okay, so I understand why the Wastegate VSV and EGBV VSV are disconnected. Because the EBC controls this by using these as Wastegates. However, I am clueless as to why the IACV VSV is capped of from the boost line(pressure tank). Shouldn't this be operated as stock?? Also I've checked the IACV continuity and I'm measuring 400-600 kiloOhm. Which is not good(should be 38,5-44,5 Ohm according to the manual). So I'm pretty sure it's busted. Quote Link to comment Share on other sites More sharing options...
DJT88 Posted May 13, 2013 Author Share Posted May 13, 2013 Can anyone understand the setup, like it has been on my car? see pic above... especially the IACV part.. I can't see how it could have worked Quote Link to comment Share on other sites More sharing options...
mellonman Posted May 13, 2013 Share Posted May 13, 2013 have a look at the link i put in and down in the replies i put in another link to max boost which shows various ways for fitting a boost controler, but i did have a quick look at your set up yesturday and didnt understand what was done fully. (im at work now and cant see it) you need to pumb it back to normal and work back from there try TTC, your boost controler is on right? i know if they are switch off they can stop boost being made. has it ever made the correct boost? has anything been changed recently? Quote Link to comment Share on other sites More sharing options...
DJT88 Posted May 13, 2013 Author Share Posted May 13, 2013 (edited) Hi thanks! yeah boost controller is on.. I can also hear it when boosting. I have made proper boost before, up to 1 bar and holding fine. I'm going to try TTC first today, but can't really go back to stock because I've found out that my IACV and EGBV vsv's are nackered. (Ohm value several 100 kiloOhms) edit: most recent changes are: CW SMIC and before that a Catback exhaust. Dyno I did over a year back looked normal(stock) to me, although the dip in power might be a little too much? https://dl.dropboxusercontent.com/u/3472574/Dyno_run_2011-10-26.jpg Edited May 13, 2013 by DJT88 (see edit history) Quote Link to comment Share on other sites More sharing options...
mellonman Posted May 13, 2013 Share Posted May 13, 2013 the EGBV is not needed with boost controler if i remember right, but if the IACV is the one thats at the top at the back nearest the driver then that is your issue right there, as this is what makes the second turbo come on line Quote Link to comment Share on other sites More sharing options...
DJT88 Posted May 13, 2013 Author Share Posted May 13, 2013 OK, I'm getting somewhere! I've just tried TTC mode succesfully. I can see the actuators and rods(to the valves) remain open and get a totally different engine sound. I'm also getting boost, so both turbo's are OK. HOWEVER, The issue that the car holds back above a 0.5 bar of boost still remains in exactly the same manner as before :O This makes me think I might have bad coil packs which can't handle higher boost than 0.5 bar(or my tuning is off). I've recently replaced all coil pack clips so they are OK. Spark plugs are in the car for about 2500 miles now. Next to try is running without the piggyback... Quote Link to comment Share on other sites More sharing options...
Ian C Posted May 13, 2013 Share Posted May 13, 2013 Coil packs/clips should manifest as a misfire, and a big one to keep boost down to 0.5v. Quote Link to comment Share on other sites More sharing options...
Chris Bailey Posted May 13, 2013 Share Posted May 13, 2013 Can you not just run it in TTC mode for Dragonball? Quote Link to comment Share on other sites More sharing options...
JasonR24 Posted May 13, 2013 Share Posted May 13, 2013 Can you not just run it in TTC mode for Dragonball? He's still getting the same problem in TTC mate... I thinking try replacing all the bits you know are faulty and then plumb it back to stock. Then if that fixes it you can work the mods back in to find whats faulty. Quote Link to comment Share on other sites More sharing options...
Chris Bailey Posted May 13, 2013 Share Posted May 13, 2013 He's still getting the same problem in TTC mate... I thinking try replacing all the bits you know are faulty and then plumb it back to stock. Then if that fixes it you can work the mods back in to find whats faulty. My bad.... I only read he got boost in TTC mode Quote Link to comment Share on other sites More sharing options...
DJT88 Posted May 13, 2013 Author Share Posted May 13, 2013 ok, without the piggyback same result... no problem there. but check this video out... (usually I'm not the kind of guy that revs their car without it moving) But when I floor it(stationary), it hesitates around 2500~3000 rpm. but flys up when it passes 3000 rpm. If I rev it without fully pressing the accelerator (feathering it somewhat half-way) it revs more fluently. Quote Link to comment Share on other sites More sharing options...
Ian C Posted May 13, 2013 Share Posted May 13, 2013 I'd get the fuelling checked on that, sounds like it's running really rich around that area and washing the spark out. It'd fit with your random piggyback install. Pulling it out would also be a good next step, as long as you know you've got stock sized injectors. Quote Link to comment Share on other sites More sharing options...
DJT88 Posted May 13, 2013 Author Share Posted May 13, 2013 I'd get the fuelling checked on that, sounds like it's running really rich around that area and washing the spark out. It'd fit with your random piggyback install. Pulling it out would also be a good next step, as long as you know you've got stock sized injectors. This vid was without the piggyback did the same with it installed though. How would one go about checking the fuelling? Or would I be better off having it checked by a tuner/garage with the right know-how? If so, it'll probably have to wait till after Dragonball. Just have to limit the throttle on the trip and everything is fine. Quote Link to comment Share on other sites More sharing options...
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