SJMKIV Posted June 20, 2012 Share Posted June 20, 2012 Hey guys, I'm having some trouble with fuel cut on my bpu supra ('95 J-spec). I have a greddy boost cut controller installed and as the instructions say, I've kept the setting to just under 4.3v (for a 1993 - 1995 supra). Somehow, I'm hitting fuel cut at the red line. Instead of reaching the rev limiter at the red line, it hits fuel cut and the check engine light comes on for a moment. When scanned with an OBD scanner, the fault shows up as 34, which is Turbo Pressure Malfunction. The car is running about 1.15 - 1.18 bar max of boost WOT in 3rd. Can anyone help me with adjusting the BCC to avoid fuel cut? Thanks for the help! SJ Quote Link to comment Share on other sites More sharing options...
fordy_alexsupra Posted June 20, 2012 Share Posted June 20, 2012 Try Lowering the volatage to 4.1v Quote Link to comment Share on other sites More sharing options...
SteveC Posted June 20, 2012 Share Posted June 20, 2012 The voltage you've set it to would seem correct for the year, but are you 100% certain it's wired in correctly? You mentioned that you used an OBD scanner to read the fault code; out of interest, what type did you use? Quote Link to comment Share on other sites More sharing options...
SJMKIV Posted June 20, 2012 Author Share Posted June 20, 2012 Thanks for the replies. So it turns out that the wiring was incorrect. Did a few runs after fixing the wiring to fine tune the voltage adjustment. I've tried from 4.25v to 4.3v. The car doesn't hit fuel cut now, but is stuttering and hesitating closer to the red line. I know that it isn't the spark plugs or old coil pack connectors causing the stuttering as before the BCC fitted, the car would rev smoothly to the redline at 1.15bar till it hit fuel cut. Any idea how to adjust the BCC to avoid this? It has to be an issue with the BCC adjustment as when I disconnect the BCC, the car runs well (apart from hitting fuel cut). As for the wiring, the Red wire is going to a 12v power source, the Black wire is going to ground, Green wire is towards the ECM to the Turbo Pressure Sensor, White wire is away from ECM towards the Turbo Pressure Sensor. Please do help! SteveC, I'll check on the type of OBD scanner and get back to you Thanks! SJ Quote Link to comment Share on other sites More sharing options...
SteveC Posted June 20, 2012 Share Posted June 20, 2012 I doubt that any further adjustment to the BCC voltage will eliminate the hesitation towards the red line. On the basis that the car runs up to the red line without hesitation with the BCC disconnected, then I'd guess it must be either: a) suspect wiring/a bad connection, or b) a faulty BCC. Have you wired to the ECU connections in the attached diagram? Quote Link to comment Share on other sites More sharing options...
fordy_alexsupra Posted June 20, 2012 Share Posted June 20, 2012 Do you have a Electronic or Manual Boost Controller? Mine stuttered at high revs until I fiddled with 'gain' setting! Quote Link to comment Share on other sites More sharing options...
SJMKIV Posted June 20, 2012 Author Share Posted June 20, 2012 I doubt that any further adjustment to the BCC voltage will eliminate the hesitation towards the red line. On the basis that the car runs up to the red line without hesitation with the BCC disconnected, then I'd guess it must be either: a) suspect wiring/a bad connection, or b) a faulty BCC. Have you wired to the ECU connections in the attached diagram? my BCC is wired up exactly like in the diagram you have posted. I'll have to look at the wiring and connections again tomorrow. Quote Link to comment Share on other sites More sharing options...
SJMKIV Posted June 20, 2012 Author Share Posted June 20, 2012 Do you have a Electronic or Manual Boost Controller? Mine stuttered at high revs until I fiddled with 'gain' setting! I have an Electronic boost controller - Blitz SBC ID. Did you increase or decrease your gain setting? Could you tell me what its finally set at? Quote Link to comment Share on other sites More sharing options...
fordy_alexsupra Posted June 20, 2012 Share Posted June 20, 2012 Good! Mine is Greddy for example On low setting, boost 15%, Gain 10% On High setting, Boost 25%, Gain 20% Tip, Reset everything to 0 or stock and set the boost first, when you are happy, set the gain second... ect Quote Link to comment Share on other sites More sharing options...
SJMKIV Posted June 20, 2012 Author Share Posted June 20, 2012 Good! Mine is Greddy for example On low setting, boost 15%, Gain 10% On High setting, Boost 25%, Gain 20% Tip, Reset everything to 0 or stock and set the boost first, when you are happy, set the gain second... ect I'll try this out first thing tomorrow, lets hope the hesitation towards redline goes away with this! Thanks! Not able to get sleep thinking about how to get my supe to work fine!! Quote Link to comment Share on other sites More sharing options...
fordy_alexsupra Posted June 20, 2012 Share Posted June 20, 2012 haha So is it feeling like power, no power, power, no power? Like rocking in your seat back and forth? Quote Link to comment Share on other sites More sharing options...
SteveC Posted June 20, 2012 Share Posted June 20, 2012 Bear in mind that you'll only be able to post on here a few more times before having to join up for £10. (the posting limit before joining is around 40 posts) Quote Link to comment Share on other sites More sharing options...
fordy_alexsupra Posted June 20, 2012 Share Posted June 20, 2012 £10 worth spending indeed! Quote Link to comment Share on other sites More sharing options...
SJMKIV Posted June 20, 2012 Author Share Posted June 20, 2012 haha So is it feeling like power, no power, power, no power? Like rocking in your seat back and forth? Nope, its just feels like a lot of hesitation while revving at full boost (i.e. 1.15bar about). Maybe a slight rocking feeling, but not very obvious. Just feels like something is holding it back from revving freely. But again, with the BCC disconnected, it revs perfectly well (apart from fuel cut). I'll try adjusting the SET and GAIN again on my boost controller tomorrow and see if that helps. Is there something else apart from this that could be worth looking into? SteveC, I'll definitely be joining up after I reach my posting limit. Would I get an email from the Mods asking me to sign up? or is there a link I can go to join? Thanks! SJ Quote Link to comment Share on other sites More sharing options...
fordy_alexsupra Posted June 20, 2012 Share Posted June 20, 2012 try having your gain just below your boost like i stated try that first to rule it out! ggo to your profile there is a subscription link somewhere. Quote Link to comment Share on other sites More sharing options...
SteveC Posted June 20, 2012 Share Posted June 20, 2012 ...I'll definitely be joining up after I reach my posting limit. Would I get an email from the Mods asking me to sign up? or is there a link I can go to join? At the top right of the page click on 'Settings', then on that page on the left-hand side under 'My settings' click on 'Paid subscriptions'. Quote Link to comment Share on other sites More sharing options...
SJMKIV Posted June 20, 2012 Author Share Posted June 20, 2012 Subscription done. Thanks guys. Will try out your suggestions tomorrow and revert with the outcome. Very eager and hope it works! Do let me know if you think of anything else that could possibly be the issue. SJ Quote Link to comment Share on other sites More sharing options...
fordy_alexsupra Posted June 20, 2012 Share Posted June 20, 2012 Cool also set the to EBC to stock settings (should see around, 0.65 1st turbo, 1.1 2nd turbo at high revs) See if this removes the problem first. Quote Link to comment Share on other sites More sharing options...
SJMKIV Posted June 21, 2012 Author Share Posted June 21, 2012 Cool also set the to EBC to stock settings (should see around, 0.65 1st turbo, 1.1 2nd turbo at high revs) See if this removes the problem first. So I did a few runs this morning. Even with the EBC off (stock settings) the car was very hesitant soon after the second turbo kicked in. I also tried one run with the BCC grounded to the chassis, but still the same result. Same hesitation was felt on another run with increased boost and gain settings on the EBC. Another run I did was with the BCC completely disconnected, and then it revved up extremely smoothly but obviously hit fuel cut at about 6.5k rpms. Do you guys feel that it could be a problem with the BCC itself? or something else? I'm extremely confused on how to proceed. In quite a stuck situation. Please help!! Quote Link to comment Share on other sites More sharing options...
SteveC Posted June 21, 2012 Share Posted June 21, 2012 IF you've got the voltage adjusted correctly, the wiring correct with good connections, and yet it only runs correctly with the BCC disconnected, then the BCC must be faulty. Quote Link to comment Share on other sites More sharing options...
SJMKIV Posted June 21, 2012 Author Share Posted June 21, 2012 IF you've got the voltage adjusted correctly, the wiring correct with good connections, and yet it only runs correctly with the BCC disconnected, then the BCC must be faulty. I guess I'll have to get a new BCC and then try again . Checked the wiring and connections many times today to make sure it was perfect, voltage also set to 4.3v. As for the OBDII scanner you had asked me about, it is a Launch x431 scanner. Quote Link to comment Share on other sites More sharing options...
SteveC Posted June 21, 2012 Share Posted June 21, 2012 (edited) I guess I'll have to get a new BCC and then try again . Checked the wiring and connections many times today to make sure it was perfect, voltage also set to 4.3v. Was the BCC new? Could you just exchange it for another? As for the OBDII scanner you had asked me about, it is a Launch x431 scanner. Is this the adapter type of scanner that works in conjunction with a mobile phone or a laptop, or is it a stand-alone unit? The reason I ask is that I was under the impression that a 1995 Supra was not OBDII and would only communicate with genuine Toyota workshop scanners or perhaps other expensive Toyota specific scanners. Edited June 21, 2012 by SteveC (see edit history) Quote Link to comment Share on other sites More sharing options...
SJMKIV Posted June 21, 2012 Author Share Posted June 21, 2012 Was the BCC new? Could you just exchange it for another? Is this the adapter type of scanner that works in conjunction with a mobile phone or a laptop, or is it a stand-alone unit? The reason I ask is that I was under the impression that a 1995 Supra was not OBDII and would only communicate with genuine Toyota workshop scanners or perhaps other expensive Toyota specific scanners. It was a new BCC bought from MVP. It was an MVP BCC which I was told is exactly like the Greddy one; they are selling that since the Greddy was discontinued. Should I go with the same one? or something else? The scanner was a universal stand-alone unit Quote Link to comment Share on other sites More sharing options...
SteveC Posted June 21, 2012 Share Posted June 21, 2012 It was a new BCC bought from MVP. It was an MVP BCC which I was told is exactly like the Greddy one; they are selling that since the Greddy was discontinued. Should I go with the same one? or something else? I'd get in touch with MVP and tell them what's happening. Unless they can tell you what's causing the poor running with the BCC you have, then they should send you a new replacement. Incidentally, the Greddy BCCs specifically for a Supra are still available in the UK - well they were certainly still available a few months back. I'll check. The scanner was a universal stand-alone unit Thanks for the info. Quote Link to comment Share on other sites More sharing options...
SteveC Posted June 21, 2012 Share Posted June 21, 2012 The Greddy BCCs specifically for a MkIV Supra are still available in the UK from here for £73.89 plus shipping. Quote Link to comment Share on other sites More sharing options...
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