Guest sco350 Posted May 24, 2012 Share Posted May 24, 2012 got a problem with my auto jdm tt with 5 speed manual conversion, i've read loads of posts and nothing else seem to be like this, i've done the usual of changing plugs and checking wiring, coils etc. if no one has any ideas how to fix it can they recommend a place that does good diagnostics in central scotland. the car starts and runs fine in each gear and both turbos come in and out as expected at all revs and throttle positions until just under 6000 when it hits what feels like a rev limiter. this is not a misfire on one or two cylinders it is either cutting the ignition or fueling totally for about a second and then continues like this. even more strange is that about one time in ten it runs perfectly and red lines without the slightest problem. even in neutral with your foot to the floor it just sits at 5800 rpm, if you are very gently on the throttle with very little load on the engine it will red line through. any ideas cos i'm lost as what to try next. Quote Link to comment Share on other sites More sharing options...
Nic Posted May 25, 2012 Share Posted May 25, 2012 (edited) Is the engine a standard 2JZ-GTE or a VVTi 2JZ-GTE? Any modifications to the car and what boost is it running? Do you know what spark plugs are fitted? Have you checked the ECU for fault codes? http://www.mkivsupra.net/vbb/showthread.php?35920-How-To-Check-the-diagnostics-codes&highlight=codes Edited May 25, 2012 by Nic (see edit history) Quote Link to comment Share on other sites More sharing options...
Ian C Posted May 25, 2012 Share Posted May 25, 2012 Could this be fuel cut? If you're only just tipping into 1bar of boost at those revs it'll behave the way you describe. Quote Link to comment Share on other sites More sharing options...
Nic Posted May 25, 2012 Share Posted May 25, 2012 Could this be fuel cut? If you're only just tipping into 1bar of boost at those revs it'll behave the way you describe. That was my first thought but he says it does it in neutral as well. Quote Link to comment Share on other sites More sharing options...
listy Posted May 25, 2012 Share Posted May 25, 2012 Mine does this sometimes and is a TT 5spd, and I'm pretty sure its fuel cut as it only happens when I floor it. Not sure about the neutral thing though, bit of a stumper for me. Quote Link to comment Share on other sites More sharing options...
Guest sco350 Posted May 25, 2012 Share Posted May 25, 2012 the plugs have been changed and it made no difference ,its got a fuel cut defender and it does this on standard boost or the max of 1.2 bar. this is really strange as there is no engine fault codes either. the engine will pull full throttle no problem till 5800 rpm then no more. Quote Link to comment Share on other sites More sharing options...
TheTurtleshead Posted May 25, 2012 Share Posted May 25, 2012 I know exactly what that is. You had to bypass the neutral safety switch on the engine loom to make it think it's in neutral and therefore allow it to start. Therefore the ECU believes that it is in neutral all the time and imposes a 5.8k-6k rev limit. You have to cut a wire close to the ECU plug on the engine loom to overcome this. I will go check which one I cut and post it up soon Quote Link to comment Share on other sites More sharing options...
TheTurtleshead Posted May 25, 2012 Share Posted May 25, 2012 (edited) Here we go, my previous thread about this. Pin 67. http://www.mkivsupra.net/vbb/showthread.php?249622-Neutral-safety-switch-Auto-Manual-Conversion-Engine-Light-Problem-5800-rev-limit As you will notice, I still had an error code that I thought was due to me cutting this wire. However it was just the standard and very common supra error code 42, which is something else entirely. I did not suffer any ill effects from cutting this wire. I strongly urge you to cut it a way back from the ECU plug, so that if you need to, you have some wire to play with when you go to join it back together! Edited May 25, 2012 by TheTurtleshead (see edit history) Quote Link to comment Share on other sites More sharing options...
Guest sco350 Posted May 25, 2012 Share Posted May 25, 2012 sounds worth a try, i'll look out the electrical drawings and have a go on sunday. will post if it works either way. Quote Link to comment Share on other sites More sharing options...
David P Posted May 25, 2012 Share Posted May 25, 2012 (edited) got a problem with my auto jdm tt with 5 speed manual conversion, i've read loads of posts and nothing else seem to be like this, i've done the usual of changing plugs and checking wiring, coils etc. if no one has any ideas how to fix it can they recommend a place that does good diagnostics in central scotland. the car starts and runs fine in each gear and both turbos come in and out as expected at all revs and throttle positions until just under 6000 when it hits what feels like a rev limiter. this is not a misfire on one or two cylinders it is either cutting the ignition or fueling totally for about a second and then continues like this. even more strange is that about one time in ten it runs perfectly and red lines without the slightest problem. even in neutral with your foot to the floor it just sits at 5800 rpm, if you are very gently on the throttle with very little load on the engine it will red line through. any ideas cos i'm lost as what to try next. This makes me think your ignition timing could be advanced too much for the octane fuel you are using, making the knock sensors kick in at WOT but not on light throttle? Edited May 25, 2012 by David P (see edit history) Quote Link to comment Share on other sites More sharing options...
mihai Posted July 10, 2013 Share Posted July 10, 2013 Nice read because i have the same problem, but mines cut the fuel at 3000 rpm, I did the auto to r154 conversion. have you sort it ? Quote Link to comment Share on other sites More sharing options...
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