SJMKIV Posted December 30, 2013 Share Posted December 30, 2013 Hey Guys, I've been having trouble with my FCD for a while now and not being able to resolve it. Let me give you some background. My car is 1995 TT BPU+ Jspec Supra. At the time I went BPU, I had bought a MVP boost cut controller to prevent fuel cut. The unit was set to clamp at 4.3v. But at full boost, the car would hesitate a lot and not rev up smoothly. This would not happen with the BCC disconnected, but obviously would hit fuel cut after 3secs over 1bar. Tried with different clamp settings, but still the same problem. I had started a thread at that time and followed the advice given by many of you, and also had MVP replace my BCC with a new one, but yet the problem persisted and I finally just had it disconnected. Here is that thread: http://mkivsupra.net/vbb/showthread.php?271885-Greddy-Boost-Cut-Controller-setting-help! Thinking there maybe some issue with the MVP unit, I bought a Turbosmart FCD-2. This unit has clamp and release settings. Set to clamp at 4.3v. Shockingly I faced the same problem!! The car would hesitate a lot with the throttle wide open and not rev up freely. Tried with various settings for clamp - 4.1v-4.8v! At full boost, it seemed that the car was running overly rich as my eyes started burning (as the runs were done on a dyno), low 10s AFR. This wouldn't happen when the FCD was disconnected and did a run at full boost. As for the wiring, I've checked it time and time again and 100% sure its correct. I'm tapping into the black/yellow turbo pressure sensor wire with the FCD wired between the turbo pressure sensor and the ECU. I've even tried various sources for power and ground. I even wired the unit up outside the car to check its functioning, and its clamping the voltage just as it should. I'm certain that there is nothing wrong with the FCD itself. Can anyone help with this? Its been a long time and Im struggling with this problem. It seems to be such a basic device, and no one else is facing a problem like this! Its sad that I have to lift off within 3secs off it crossing 1bar to avoid hitting fuel cut. Not being able to enjoy the potential of the car. Is there any other solution to this? Any possible help with be immensely appreciated! Thanks a ton in advance!! and a very Happy New Year to you all! SJ Quote Link to comment Share on other sites More sharing options...
LOGIE Posted January 1, 2014 Share Posted January 1, 2014 Id also like to know how to set one of these up as it is on my to do list. Quote Link to comment Share on other sites More sharing options...
gdog1989 Posted January 1, 2014 Share Posted January 1, 2014 I think its the same issue as what im having and ive been told that its either my spark plugs coilpacks or the clips on the coilpacks, when it starts to boost it feels like its pulling back and sounds like backfiring. - - - Updated - - - I think its the same issue as what im having and ive been told that its either my spark plugs coilpacks or the clips on the coilpacks, when it starts to boost it feels like its pulling back and sounds like backfiring. Quote Link to comment Share on other sites More sharing options...
SJMKIV Posted January 2, 2014 Author Share Posted January 2, 2014 I think its the same issue as what im having and ive been told that its either my spark plugs coilpacks or the clips on the coilpacks, when it starts to boost it feels like its pulling back and sounds like backfiring. Are you having this issue only when your FCD is connected? or even without? For me, I don't think it can be the spark plugs or the coilpacks because with the FCD disconnected, it runs perfectly and boosts smoothly (obviously hitting fuel cut though eventually). I have this issue only when the FCD is connected between the Turbo Pressure Sensor and the ECU. SJ Quote Link to comment Share on other sites More sharing options...
Chris Wilson Posted January 2, 2014 Share Posted January 2, 2014 Can you measure the voltage seen at the ecu from the FCD, under boost? Nice to read a well formatted post with clear questions, in good English! They are becoming rarer. Quote Link to comment Share on other sites More sharing options...
SJMKIV Posted January 6, 2014 Author Share Posted January 6, 2014 Can you measure the voltage seen at the ecu from the FCD, under boost? Nice to read a well formatted post with clear questions, in good English! They are becoming rarer. Thanks Chris I have checked, it keeps fluctuating very low - 3.3 to 3.5v, at full boost. I have also checked the voltage at the FCD from the turbo pressure sensor - it climbs as it should going > 4.5 - 4.7v at full boost But again I should mention that when I connected up the FCD outside the vehicle and gave it 5v (as though thats the signal its getting from the TPS) - the output was reading correctly at 4.3v (or whatever other setting i would change it to). SJ Quote Link to comment Share on other sites More sharing options...
Chris Wilson Posted January 6, 2014 Share Posted January 6, 2014 Check the reference line voltage at the MAP sensor with the FCD connected up in the vehicle, is it 5V exactly? It should be. Check at other sensors, like TPS and ecu water temp sensor. Quote Link to comment Share on other sites More sharing options...
SJMKIV Posted January 6, 2014 Author Share Posted January 6, 2014 Check the reference line voltage at the MAP sensor with the FCD connected up in the vehicle, is it 5V exactly? It should be. Check at other sensors, like TPS and ecu water temp sensor. I have checked the line voltage at the turbo pressure sensor, its 5v SJ Quote Link to comment Share on other sites More sharing options...
Nodalmighty Posted January 6, 2014 Share Posted January 6, 2014 What are the clamp and release settings on your TS FCD? Lyndon. Quote Link to comment Share on other sites More sharing options...
SJMKIV Posted January 6, 2014 Author Share Posted January 6, 2014 What are the clamp and release settings on your TS FCD? Lyndon. Clamp is little over 5.5 (somewhere between 5.5 & 6 translates to 4.3v) and release is at 8. I've also tried various other settings - clamp 6 release 8, clamp 6.5 release 9 etc etc. SJ Quote Link to comment Share on other sites More sharing options...
Nodalmighty Posted January 6, 2014 Share Posted January 6, 2014 Does it draw it's power from the 5v line or is it powered by 12v? Lyndon. Quote Link to comment Share on other sites More sharing options...
SJMKIV Posted January 6, 2014 Author Share Posted January 6, 2014 Does it draw it's power from the 5v line or is it powered by 12v? Lyndon. Powered by 12v SJ Quote Link to comment Share on other sites More sharing options...
Nodalmighty Posted January 6, 2014 Share Posted January 6, 2014 So the wire that you feed 5v into to test is the same wire you connect to the sensor side and the wire that gives 4.3v under test is the one you wire to the ecu? Lyndon. Quote Link to comment Share on other sites More sharing options...
SJMKIV Posted January 6, 2014 Author Share Posted January 6, 2014 So the wire that you feed 5v into to test is the same wire you connect to the sensor side and the wire that gives 4.3v under test is the one you wire to the ecu? Lyndon. Yes, thats exactly what I did. When connected to the car, its tapped into the black/yellow wire. Quote Link to comment Share on other sites More sharing options...
JasonR24 Posted January 6, 2014 Share Posted January 6, 2014 Just thought I'd check but what supporting mods did you do before putting the boost pressure up? If you've done all the mods you should then id say coil pack or clips. Quote Link to comment Share on other sites More sharing options...
SJMKIV Posted January 6, 2014 Author Share Posted January 6, 2014 Just thought I'd check but what supporting mods did you do before putting the boost pressure up? If you've done all the mods you should then id say coil pack or clips. All necessary mods are done: - Double decat - RSR Cat back exhaust - Walbro fuel pump - Denso IK24 spark plugs - Apexi intake - turbosmart supersonic BOV - Greddy 3 row FMIC - Koyo radiator The car revs up perfectly, even to 1.2bar when the FCD is not connected (obviously eventually hitting fuel cut), but only when its connected, it hesitates a lot and doesnt rev freely at all. If the coil packs or clips have gone bad, shouldn't it cause an issue even when the FCD is not connected? Thanks, SJ Quote Link to comment Share on other sites More sharing options...
jza800 Posted January 6, 2014 Share Posted January 6, 2014 i have exactly the same symptoms when i fittet my hks fcd on my j.spec engine.. so you ae not the only one.. but i have not jet found the reson why Quote Link to comment Share on other sites More sharing options...
Nodalmighty Posted January 6, 2014 Share Posted January 6, 2014 (edited) Yes, thats exactly what I did. When connected to the car, its tapped into the black/yellow wire. I'm sure this is just terminology thing but when you say tapped you mean Yellow and Black wire has been cut and the wires from the FCD connected it each end. (Tapping usually refers to integrating with the existing wire uncut). Lyndon. Edited January 6, 2014 by Nodalmighty (see edit history) Quote Link to comment Share on other sites More sharing options...
SJMKIV Posted January 6, 2014 Author Share Posted January 6, 2014 I'm sure this is just terminology thing but when you say tapped you mean Yellow and Black wire has been cut and the wires from the FCD connected it each end. (Tapping usually refers to integrating with the existing wire uncut). Lyndon. Maybe I used a wrong word. What I meant was that the black/yellow wire has been cut and FCD is placed in between the cut ends. Input to FCD from the TPS - output of FCD into ECU. Hope this clarifies? Thanks! SJ Quote Link to comment Share on other sites More sharing options...
SJMKIV Posted January 8, 2014 Author Share Posted January 8, 2014 Anyone?? Quote Link to comment Share on other sites More sharing options...
Chris Wilson Posted January 8, 2014 Share Posted January 8, 2014 Maybe I used a wrong word. What I meant was that the black/yellow wire has been cut and FCD is placed in between the cut ends. Input to FCD from the TPS - output of FCD into ECU. Hope this clarifies? Thanks! SJ That sounds correct so long as you have the correct yellow / black wire Otherwise I am at a loss, all sounds correct. Quote Link to comment Share on other sites More sharing options...
Chris Wilson Posted January 8, 2014 Share Posted January 8, 2014 That sounds correct so long as you have the correct yellow / black wire Otherwise I am at a loss, all sounds correct. It does have a proper good ground and a proper, none varying 12V + connection? Have you checked *THOSE* in real time, on the car???? Quote Link to comment Share on other sites More sharing options...
SJMKIV Posted January 8, 2014 Author Share Posted January 8, 2014 That sounds correct so long as you have the correct yellow / black wire Otherwise I am at a loss, all sounds correct. I don't know how else to get rid of fuel cut. Going down the standalone ecu route maybe overkill for a BPU supra, and a huge expense! But is there any other option? SJ - - - Updated - - - i have exactly the same symptoms when i fittet my hks fcd on my j.spec engine.. so you ae not the only one.. but i have not jet found the reson why So as of now are you still hitting fuel cut? Quote Link to comment Share on other sites More sharing options...
SJMKIV Posted January 8, 2014 Author Share Posted January 8, 2014 It does have a proper good ground and a proper, none varying 12V + connection? Have you checked *THOSE* in real time, on the car???? I have tried two or three different sources for 12V power, including the car battery & 12V power from ECU. And as for the ground, I've tried the ECU ground and also chassis ground. Haven't checked the power fluctuation in real time on the car though Quote Link to comment Share on other sites More sharing options...
jza800 Posted February 8, 2014 Share Posted February 8, 2014 did you ever found the problem??? Quote Link to comment Share on other sites More sharing options...
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