Jurgen-Jm-Imports Posted September 4, 2007 Share Posted September 4, 2007 this one is for the technical guys here...car has been converted to a tt from na..(in jp) basically we have a supra with a bad missfire as soon as you accelarate near 3k it misses real bad and it basically wont drive good. on idle car revs ok -- we have tried the following new plugs and gapped. coil packs ignitor pack maf sensor.. checked injector clips ecu is gte could it be a faulty fuel pump.. any ideas would be most welcomed Link to comment Share on other sites More sharing options...
JustGav Posted September 4, 2007 Share Posted September 4, 2007 Check general fuel pressure and then work from there.. Blocked fuel filter.. Dodgy pump Blocked injectors. Iffy pressure regulator. Link to comment Share on other sites More sharing options...
Mike_Mac Posted September 4, 2007 Share Posted September 4, 2007 I've just solved a misfire on mine by tightening up my Cam Position Sensor connections (had cracked with age). Is there any error codes being stored - (13 was what mine was reading)? Also if it's idling fine, but kicking at 3000 revs then what about the various VSVs for the Turbos - any chances one of them's getting stuck and causing un-even running, only 3k is when #1 comes on-line isn't it. Finally what about the Coil Pack connectors? Link to comment Share on other sites More sharing options...
Nic Posted September 4, 2007 Share Posted September 4, 2007 Just a thought, what ECU does it have fitted? Link to comment Share on other sites More sharing options...
Tricky-Ricky Posted September 4, 2007 Share Posted September 4, 2007 Definitely sounds fuel related, and i suspect to rich, has it got a wideband AFR? Link to comment Share on other sites More sharing options...
Jurgen-Jm-Imports Posted September 4, 2007 Author Share Posted September 4, 2007 car is stock ecu... will try what was suggested... cheers for imput so far. Link to comment Share on other sites More sharing options...
jim_supra Posted September 4, 2007 Share Posted September 4, 2007 Has it had the fuel pump uprated yet? That is something that must be done when you convert to TT, The stock NA one doesn't supply enough fuel (or so I was told when I was doing my conversion). Link to comment Share on other sites More sharing options...
Jurgen-Jm-Imports Posted September 4, 2007 Author Share Posted September 4, 2007 Has it had the fuel pump uprated yet? That is something that must be done when you convert to TT, The stock NA one doesn't supply enough fuel (or so I was told when I was doing my conversion). i thought of that but was told the n/a was suffiecient. can anyone shed any light ? Link to comment Share on other sites More sharing options...
Mike B Posted September 5, 2007 Share Posted September 5, 2007 surely if it was starved of fuel it would run really well at 14:1 until it exploded. it's a twin turbo n/a...? jeeze that's a lot of work to do for what one member ever week takes off and replaces with a single.. did they swap the whole engine and gearbox, or put the TT's on an N/A block? what did the plugs look like when you had them out? Link to comment Share on other sites More sharing options...
Nic Posted September 5, 2007 Share Posted September 5, 2007 Has it had the fuel pump uprated yet? That is something that must be done when you convert to TT, The stock NA one doesn't supply enough fuel (or so I was told when I was doing my conversion). The NA uses the same fuel pump as the J-spec Supra. Link to comment Share on other sites More sharing options...
RobSheffield Posted September 5, 2007 Share Posted September 5, 2007 car is stock ecu... Stock TT ecu? Manual or auto car and manual or auto ecu? What Map sensor is on it? Stock TT? Link to comment Share on other sites More sharing options...
Sean1933 Posted September 5, 2007 Share Posted September 5, 2007 Sounds fuel related to me. Has it ever run properly since being converted? Stupid question but i had to ask. I just wondered if the injectors had been matched with the stock TT ecu. You need to check all vacuum lines for possible leaks/cracks as this would make it run lean. These may only become apparent under load. Pull the plugs after running @ load, this should give some indication of if your running rich/lean. Also need to check fuel pressure. If this irregular then possible faulty pump or blocked fuel filter/line. Then again it could also be leaky/stuck/blocked injectors. Just a case of trying things and ticking them off the list i am afraid...but i would start with checking the plugs for signs of overfuel/lean det. Link to comment Share on other sites More sharing options...
Jurgen-Jm-Imports Posted September 5, 2007 Author Share Posted September 5, 2007 update car has j-spec ecu tt,full tt conversion box everything,,, am going to take it to michel tommorrow see if he can help... we tried the new plugs and no joy. car is stock apart from intercooler Link to comment Share on other sites More sharing options...
Sean1933 Posted September 5, 2007 Share Posted September 5, 2007 update car has j-spec ecu tt,full tt conversion box everything,,, am going to take it to michel tommorrow see if he can help... we tried the new plugs and no joy. car is stock apart from intercooler I assume that includes fueling then mate? Link to comment Share on other sites More sharing options...
Jurgen-Jm-Imports Posted September 5, 2007 Author Share Posted September 5, 2007 I assume that includes fueling then mate? yep fueling is stock.. could a dodgy wastegate do this ?? Link to comment Share on other sites More sharing options...
Sean1933 Posted September 5, 2007 Share Posted September 5, 2007 As in stock TT or stock NA fueling. If its got NA injectors then you will find its running lean as the TT ECU will be running the correct duty cycle for 440cc (j=spec TT injectors) and not the stock NA injectors which i assume are smaller, 340cc maybe??? Cant see the wastgate doing this no. If it was stuck open it just wouldnt make boost...if it was stuck closed then it would overboost, but you wouldnt know about that until way into the rev range. When you pulled the plugs were they wet/sooty? Link to comment Share on other sites More sharing options...
Jurgen-Jm-Imports Posted September 5, 2007 Author Share Posted September 5, 2007 As in stock TT or stock NA fueling. If its got NA injectors then you will find its running lean as the TT ECU will be running the correct duty cycle for 440cc (j=spec TT injectors) and not the stock NA injectors which i assume are smaller, 340cc maybe??? Cant see the wastgate doing this no. If it was stuck open it just wouldnt make boost...if it was stuck closed then it would overboost, but you wouldnt know about that until way into the rev range. all pass the info into garage as all the other supras we have are big singles and dont want to try and use their injectors but i would of thought the injectors and wiring harness would of all come with the block on conversion Link to comment Share on other sites More sharing options...
vvteye Posted September 5, 2007 Share Posted September 5, 2007 Now I'm not technical but when I had exactly this problem it was sorted with coil packs and an ignition lead. Check it in the dark to see if there are any rogue electric discharges from the leads. Link to comment Share on other sites More sharing options...
Sean1933 Posted September 5, 2007 Share Posted September 5, 2007 all pass the info into garage as all the other supras we have are big singles and dont want to try and use their injectors but i would of thought the injectors and wiring harness would of all come with the block on conversion Ok mate. I assumed it was an NA block that had been converted to TT (not a good idea due to compression ratio!), but now i understand its got a complete TT engine...if thats what you mean. Let us know what it turns out to be mate, just out of interest Now I'm not technical but when I had exactly this problem it was sorted with coil packs and an ignition lead. Check it in the dark to see if there are any rogue electric discharges from the leads. Its the fact that it idles fine but once it gets to boost range it runs funny, that makes me think its fuel related and not spark. Not to mention they have already changed the coilpacks. Link to comment Share on other sites More sharing options...
Jurgen-Jm-Imports Posted September 5, 2007 Author Share Posted September 5, 2007 Let us know what it turns out to be mate, just out of interest Its the fact that it idles fine but once it gets to boost range it runs funny, that makes me think its fuel related and not spark. Not to mention they have already changed the coilpacks. yep will do, coilpacks from a fully working supra have been tried on it... will update tommorrow Link to comment Share on other sites More sharing options...
Sean1933 Posted September 9, 2007 Share Posted September 9, 2007 So what was the cause mate? Link to comment Share on other sites More sharing options...
wez_p Posted September 9, 2007 Share Posted September 9, 2007 has it been decatted & got an FCD? MattH had similar issues with his a while back & it turned out to just be the FCD wasn't turned up enough, i.e. the boost cut was kicking in & out. felt just like a misfire when driving since it kept coming on & off Link to comment Share on other sites More sharing options...
michel lane Posted September 9, 2007 Share Posted September 9, 2007 The car is sorted not ,It was a combination of items . Cam sensors and crank sensor and ECU. We had changed the ECU first as there was an after market unit on it , this allowed the car to rev past 2k now before it used to hit 2k-2.5k and die, then we ammended the loom and checked all the joints , we had to solder various connectors to get the error code function working , then changed the cam sensors , which got rid of one error code then changed the crank sensor and finally got rid of a small miss at 2k. Jobs done now , car goes really well. Link to comment Share on other sites More sharing options...
Sean1933 Posted September 9, 2007 Share Posted September 9, 2007 Cool. I assumed it wasnt ecu related as a different had been tried and no engine error codes were mentioned...which suggested it was mechanical and not electrical. Live and learn i guess! How did you deduce the problem michel? I take it you just fixed the harness, checked the error codes, then changed the sensors accordingly? Link to comment Share on other sites More sharing options...
mikeyb10supra Posted September 9, 2007 Share Posted September 9, 2007 Just a thought, what ECU does it have fitted? yep...was going to say the same thing...could be the N/A ECU therefore its fighting the map when the turbo starts coming on boost?? Link to comment Share on other sites More sharing options...
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