Fifty Posted July 13, 2009 Share Posted July 13, 2009 have any of the smaller vacuum pipies been moved or put back in the wrong location - I seem to remember reading this years back? Rich Quote Link to comment Share on other sites More sharing options...
dukenukem Posted July 13, 2009 Author Share Posted July 13, 2009 (edited) Did they not do a leakdown test for you dude to check if your system could maintain 0.8-0.9 bar? Wouldn't think it'd be the timing belt causing this, you'd surely feel it running a little on the jerky side. Yeah, they did a full leak test and said they couldn't find anything wrong, apparently it's all in good condition. Several people I've spoken to also said the timing belt can't be a tooth out otherwise I'd definately know about it (the engine revs nice and cleanly). 3 things I've noticed from the graphs, the AFR was 10.6 last month with 266 BHP and 0.56bar boost, after the service the AFR was lean at 11.9 to 11.6 with 0.54bar boost and 236BHP (I think from Homer's BPU explanation stock should be 0.76bar for J-Spec Turbo's). The second thing is the A/F Ratio is now much less responsive to changes in boost pressure. The last point is that the peaks and troughs in the graph have all shifted to occur around 500 rpm later. Does this sound like and ECU or sensor problem? I will try and post a super-imposed graph with the before and after lines on it tomorrow to clearly show the difference. Have you got your car back from AFR yet? Edited July 13, 2009 by dukenukem (see edit history) Quote Link to comment Share on other sites More sharing options...
caseys Posted July 13, 2009 Share Posted July 13, 2009 Yeah, they did a full leak test and said they couldn't find anything wrong, apparently it's all in good condition. Several people I've spoken to also said the timing belt can't be a tooth out otherwise I'd definately know about it (the engine revs nice and cleanly). 3 things I've noticed from the graphs, the AFR was 10.6 last month with 266 BHP and 0.56bar boost, after the service the AFR was lean at 11.9 to 11.6 with 0.54bar boost and 236BHP (I think from Homer's BPU explanation stock should be 0.76bar for J-Spec Turbo's). The second thing is the A/F Ratio is now much less responsive to changes in boost pressure. The last point is that the peaks and troughs in the graph have all shifted to occur around 500 rpm later. Does this sound like and ECU or sensor problem? I will try and post a super-imposed graph with the before and after lines on it tomorrow to clearly show the difference. Have you got your car back from AFR yet? I'm not really that technically minded, but maybe if your AFRs are suddenly leaner could that point to an injector/pump not flowing as it should? Or otherwise you've suddenly got more air going in. If it's consistent at a certain RPM range I would be wanting to have those looked at anyway (flow test?). Never had an issue like that myself, this is just speculative diagnosis. Again like others have said I don't understand why an AFR like that would affect boost pressure. Do you have an AFR gauge? Did you notice this behavior or just from the dyno graphs? Yes car came back on Friday, will have to arrange to take you for a spin sometime but on-call until Thursday morning. Few bits and bobs to get sorted out like my ICV and a little remap for to sort out the timing and a rich point in the map but was impressed so far with the head work they've done. I was unfortunately eating into their time to prep for TOTB, so going back to have remainder done in a month or so. Quote Link to comment Share on other sites More sharing options...
dukenukem Posted July 13, 2009 Author Share Posted July 13, 2009 Nice one Si, I look forward to a spin in it! I'm pretty much free whenever, will send you a pm at some point. I believe the boost pressure issue is separate. It may have always produced around the 0.55bar mark since I've had the car (the graphs follow more or less the same lines before and after the service). I don't have an AFR gauge, this is purely looking at the RR results. The garage have offered to whack it back on the dyno again for free to verify the graphs. A mate with a Honda S2000 said his car was driving like a slug until he reset the ECU and it re-mapped itself and has been like a different car ever since. I'm wandering if my ECU is slightly confused now with a clean air and fuel filter and needs a nudge (although more likely it's one of the sensors). Anybody know how to reset it? Do you just disconnect the battery for a couple of hours? Quote Link to comment Share on other sites More sharing options...
Abz Posted July 13, 2009 Share Posted July 13, 2009 Anybody know how to reset it? Do you just disconnect the battery for a couple of hours? Not tried it myself on the Supra, but this thread advises on how to do it: http://www.mkivsupra.net/vbb/showthread.php?t=169439&highlight=resetting+ecu Quote Link to comment Share on other sites More sharing options...
tooquicktostop Posted July 13, 2009 Share Posted July 13, 2009 I would be taking a serious look at the garage you used if they tell you a TT is all A OK when it is obviously well down on power then chuck the keys back at you and expect you to walk away happy !!!!! Quote Link to comment Share on other sites More sharing options...
pistonbroke Posted July 13, 2009 Share Posted July 13, 2009 My money is on one of your VSV's. You should put it in TTC mode to eliminate them as a problem. Looking at your graphs, your rate of power increase is the same after the dip at 3750rpm. It should, be a steeper incline at this point when both turbos go full chat, but it's clearly not. You say the garage has stated that there are no leaks in the system, so your intercooler should be fine. Quote Link to comment Share on other sites More sharing options...
Abz Posted July 13, 2009 Share Posted July 13, 2009 I would be taking a serious look at the garage you used if they tell you a TT is all A OK when it is obviously well down on power then chuck the keys back at you and expect you to walk away happy !!!!! Not helping the point, but very true... have they offered to spend a day with it in the garage and take a good look over? Being a tunning company they it would be very silly for them to service a TT Supra which then registers 193bhp and say all is well. Quote Link to comment Share on other sites More sharing options...
tooquicktostop Posted July 13, 2009 Share Posted July 13, 2009 Not helping the point, but very true... have they offered to spend a day with it in the garage and take a good look over? Being a tunning company they it would be very silly for them to service a TT Supra which then registers 193bhp and say all is well. I thought it maybe very helpful because I would be taking it back to them and insisting they find why is it so low down on power, it is not a well car for some reason and a professional tuning company should be able to tell you why If I had a car dyno low on power then pay a sum of cash for a full service and then dyno again and loose 26BHP I would expect them to already have the reason why it had lost over 10% power It could be a leak, poor intercooler or something more serious, but the answer should come from the tuner, thats what you pay them for right ?? Quote Link to comment Share on other sites More sharing options...
wkdtime Posted July 13, 2009 Share Posted July 13, 2009 (edited) My money is on one of your VSV's. You should put it in TTC mode to eliminate them as a problem. This has been mentioned a few times in this thread, this is what he should be trying first (10 mins to do) just to rule out eactly what you have just stated above. Like pissing in the wind sometimes Edited July 13, 2009 by wkdtime (see edit history) Quote Link to comment Share on other sites More sharing options...
dukenukem Posted July 13, 2009 Author Share Posted July 13, 2009 This has been mentioned a few times in this thread, this is what he should be trying first (10 mins to do) just to rule out eactly what you have just stated above. Like pissing in the wind sometimes Cheers for the advise (to everbody who suggested the same). I've by-passed the VSV's and been for a 20 mile run in TTC mode and both turbo's appear to be working as expected. Rather than a punch at 4,000rpm when the 2nd turbo kicks in there's a much more gentle/progressive surge from 3-4,000, but they appear to be running ok. Unfortunately I don't have a boost gauge so can't put any figures to it. Does that still make this exercise valid? What's next? Quote Link to comment Share on other sites More sharing options...
pistonbroke Posted July 14, 2009 Share Posted July 14, 2009 does it feel considerably quicker? Quote Link to comment Share on other sites More sharing options...
Ark Posted July 14, 2009 Share Posted July 14, 2009 I call boost leak - the graphs are all correct, apart from the low level. HOWEVER - there has been some controvercy in other clubs about Triton's dyno giving odd results ever since they over-speeded it to dyno Mick Begley's Super Lemon...I'd suggest getting a second opinion from SRR, or getting the car over to Toyoda Tech or Toyota GT for diagnosis. Quote Link to comment Share on other sites More sharing options...
dukenukem Posted July 14, 2009 Author Share Posted July 14, 2009 does it feel considerably quicker? Not really no. There's obviously the lack of low end torque as the exhaust is being split between 2 turbo's rather than just one, and there's no sudden boost at 4,000rpm, which always made it feel fast. Also, it sounded like I had a small dump valve fitted. Usually the 'pssst' of the waste gate is really subtle, but when running in TTC it was about 3 or 4 times louder (is this the leak your talking about?). I've tried to superimpose the 2 graphs using a photocopier. The red lines are a month ago before the service, the blue lines are after the service and timing belt change. The turbo pressure does slightly tail off (blue line), when it was nice and flat before, but this is also excentuated by the fact I've superimposed it slightly on the wonk. The more worrying part is the fact that the peaks and troughs are occuring around 400 rpm later, re-installing my fear that the timing belt is a degree out. The engine seems to rev and tick over perfectly though. You can see the air-fuel ratio isn't reacting as quickly to the changes in boost pressure compared to before (ECU or sensors?). It's all Bollocks..Boost Pressure.pdf Quote Link to comment Share on other sites More sharing options...
dukenukem Posted July 14, 2009 Author Share Posted July 14, 2009 One thing I forgot to mention though... in the first Dyno test my tyres were verging on illegal, practically slicks. The day I dropped the car off to be serviced I had just put some brand new Pirelli P-Zero's on the back, adding about another 14mm (guess) of tread to the rear wheel diameter. How is the engine rev's recorded during a dyno? Is this simply done by the fact that the car (Auto) is in 3rd gear i.e. a 1:1 gear ratio, so they are purely basing it on the rpm of the big rolling pin or do they connect something to the engine? Quote Link to comment Share on other sites More sharing options...
pistonbroke Posted July 14, 2009 Share Posted July 14, 2009 You can check the timing easily enough by just taking the cover off and seeing if all the marks line up at TDC. I doubt you'll find anything though, as I'm sure a tooth out on the timing would make it run like crap. If you're still not reaching the desired boost level, (and I'd think you'd notice it of your were ) then we're back to there being a leak somewhere. Quote Link to comment Share on other sites More sharing options...
dukenukem Posted July 14, 2009 Author Share Posted July 14, 2009 You can check the timing easily enough by just taking the cover off and seeing if all the marks line up at TDC. I doubt you'll find anything though, as I'm sure a tooth out on the timing would make it run like crap. If you're still not reaching the desired boost level, (and I'd think you'd notice it of your were ) then we're back to there being a leak somewhere. Cheers, checking timing is next on the list, I was thinking you would have to take the rad off though to get a proper good look at all the positions? There must be a leak somewhere, but I'm gutted they didn't find it during the service. Maybe a slightly seized waste gate or something. What about the AFR's though? Is it normal to have to reset the ECU after changing the fuel and air filters? I expect they did the dyno shortly after changing these, so maybe the ECU hadn't had time to adjust itself? Probably wishful thinking. More likely a buggered sensor. [sAD][/sAD] Quote Link to comment Share on other sites More sharing options...
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