Guest |306| Posted October 15, 2009 Report Share Posted October 15, 2009 Ray, My buddy and I have been perplexed by this issue. I'm currently on the stock fuel system of my Supra (550cc injectors, 260lph denso pump, 43 psi fuel pressure). When we log our data, we get some pretty ridiculous injector duty cycles~ in the order of 160%. We know this is highly unlikely and almost impossible. My car remains rich @ 11-11.5 AFR's @ ~17-18psi. On the fuel table, the highest we have is 97% (I know is high, but we're testing, very conservative timing), but at that same value it reads well over 150% for Inj Duty Cycle. This leads me to believe that maybe the injectors are set up wrong, OR the values are being calculated incorrectly (most likely the former than the latter). What do you think? Do you have the fuel injector set up for the stock fuel system of a USDM 2JZ? I could use calculators available online, but I'd just like to make sure my dead time, pulse width, peak and hold are set up correctly. Thanks, Jeremy Quote Link to comment Share on other sites More sharing options...
Guest |252| Posted October 15, 2009 Report Share Posted October 15, 2009 My first guess would be warmup enrichment. What is the temp of the ECT and IAT while you were testing? Quote Link to comment Share on other sites More sharing options...
Guest |306| Posted October 15, 2009 Report Share Posted October 15, 2009 Wait.. why would ECT and IAT matter? Isn't Inj Duty Cycle simply calculated with respect to injector pulse width at a given rpm? Our IAT was 45-50C and the ECT was in the ~90C Quote Link to comment Share on other sites More sharing options...
rayhall Posted October 15, 2009 Report Share Posted October 15, 2009 Jeremy, Please email me your map. I will load it into a V88 and run it on the engine emulator. I will then be able to see what is going on. Ray. Quote Link to comment Share on other sites More sharing options...
Guest |306| Posted October 16, 2009 Report Share Posted October 16, 2009 Engine emulator? That's sweet I'll email you now. Thanks! EDIT: Email sent to [email protected] Thanks again, Ray Quote Link to comment Share on other sites More sharing options...
rayhall Posted October 19, 2009 Report Share Posted October 19, 2009 Jeremy, I have run your map, and can confirm injector duty is going way over 100%. I can also see why...Your fuel table has values of around 40 at idle and by only 100 kpa (0 psi gauge) you have values of 98. This means you have one or more of these problems. 1. Fuel pump is faulty or too small causing fuel pressure to drop at higher rpm and load. 2. Fuel pressure regulator is not the standard Toyota and is made by some "Performance" company. 3. Fuel pressure regulator does not have a vacuum/pressure line connected. 4.The injectors are peak and hold, and you have saturated selected. 5. Your scaling of the map sensor table is wrong. Also when you find the problem, I would dramatically reduce the number of load sites in the fuel table. Having so many just makes tuning a long process. Quote Link to comment Share on other sites More sharing options...
Guest |306| Posted October 19, 2009 Report Share Posted October 19, 2009 Thanks Ray. I'm still on 100% stock fuel system. 1. Fuel pump is faulty or too small causing fuel pressure to drop at higher rpm and load. - Possible, but I have not seen a Denso Fuel Pump fail. Walbros, maybe, but not Denso. I'll will try to run some checks. 2. Fuel pressure regulator is not the standard Toyota and is made by some "Performance" company. - Still bone stock 3. Fuel pressure regulator does not have a vacuum/pressure line connected. -I have not modified the fuel system at all 4.The injectors are peak and hold, and you have saturated selected. - I'm not sure if stock OEM are peak and hold or saturated. I have saturated on the settings 5. Your scaling of the map sensor table is wrong. - I've confirmed with my boost gauge and the map sensor that I've scaled it properly. The reason there were some 98% fuel values at 100kpa in the map is that we have not touched that part yet. I guess I'll check on 1 and 4. Thanks for your help again. EDIT: Thanks, Ray, it looks like Stock TT injectors are peak and hold, not saturated. It looks like it was not set up correctly. http://www.robietherobot.com/Storm/fuel ... rguide.htm Can you please still send me the base map for a USDM Supra just to make sure my the rest of my dead time values and peak and hold values make sense? I can't find any specifics on the stock Supra injectors Thanks, Jeremy Quote Link to comment Share on other sites More sharing options...
rayhall Posted October 19, 2009 Report Share Posted October 19, 2009 Jeremy, The stock injectors are not peak and hold. That website is wrong. I will email you the map. Quote Link to comment Share on other sites More sharing options...
Guest |306| Posted October 19, 2009 Report Share Posted October 19, 2009 EDITED: I think I found what's wrong Quote Link to comment Share on other sites More sharing options...
Guest |263| Posted October 19, 2009 Report Share Posted October 19, 2009 Jeremy, The stock injectors are not peak and hold. That website is wrong. I will email you the map. I think USDM and JDM Supras MKIV have different injectors. JDM 440cc saturated, USDM 550cc Peak and Hold (with inline resistor pack, so you can drive it as saturated injectors). Quote Link to comment Share on other sites More sharing options...
Guest |306| Posted October 19, 2009 Report Share Posted October 19, 2009 ^Stock USDM are 550cc and JDM are 440cc. It seems like you may be right. Thanks Quote Link to comment Share on other sites More sharing options...
Guest |306| Posted October 20, 2009 Report Share Posted October 20, 2009 Another wrench thrown in this scenario... I am reading that USDM injectors are in fact Peak and Hold. However, someone has told me that: Toyota installed a resistor pack for this injectors, making them run like Saturated ones. Ok, if this is true, I must set up my injectors as saturated. One perplexing question though... why would Toyota throw peak and hold injectors when they are going to use them as saturated ones anyway? I'm confused UPDATE: Looks like yes, there is a resistor box for the low impedance, stock injectors. The resistor pack can be rerouted and avoided and run the injectors directly as peak and hold. My only issue now is finding the appropriate peak and hold values for my injectors or just keep the resistors and run them as saturated. UPDATE 2: Looks like there was a typo in my tune from John and he cleared it all up. If I was removing the stock resistor pack, I should go peak and hold but if I kept it, it should be saturated. Thanks John. Quote Link to comment Share on other sites More sharing options...
rayhall Posted October 20, 2009 Report Share Posted October 20, 2009 Jeremy, The map I sent you has saturated selected. These setting have worked on USA and JDM cars without problems. If you want more accurate settings, then send the injectors to Paul at YawPower. He will give you the perfect settings. Quote Link to comment Share on other sites More sharing options...
Guest |306| Posted October 21, 2009 Report Share Posted October 21, 2009 Thanks Ray. I have one more question. I'm comparing the injector deadtimes for the pcl map you sent me in april vs the one you sent me a few days ago, and they are completely different: April Voltage- ms 9- 1.265 10- 1.100 11- 1.000 12- 0.900 13- 0.845 14- 0.800 Oct 09 9- 1.265 10- 0.920 11- 0.735 12- 0.550 13- 0.445 14- 0.340 Which one is the correct one? Thanks, Jeremy Quote Link to comment Share on other sites More sharing options...
rayhall Posted October 21, 2009 Report Share Posted October 21, 2009 The map I emailed you the other day, is what has been loaded into ECU for many months. No one has reported any problems. I do not know about any earlier map. Ray. Quote Link to comment Share on other sites More sharing options...
Guest |306| Posted October 21, 2009 Report Share Posted October 21, 2009 Alright Ray, that's good enough for me I'm just trying to be consistent Quote Link to comment Share on other sites More sharing options...
Guest |306| Posted October 26, 2009 Report Share Posted October 26, 2009 Ray, How is the fuel table created in the software? I understand the fuel table is by percentages, but how is 100% determined? For instance, if I enter in 75% for my entire table, where does Vi-pec get the values? Is it 75% of the available pulsewidth given the RPM (after accounting for deadtime)? I'm just trying to wrap my head around my issue. If I altered my deadtime values to the lower one, it only provides me approximately 3% more fuel.. so that may be an issue, but not large enough to cause "150%" duty cycles. It is possible I have dirty injectors... I'll get them cleaned over the winter and flow tested. I just find this whole situation weird, as I've been having to remove fuel, not add it. Meaning if the injectors are wideopen for this duration, then shouldn't I start leaning out? 100% injector duty cycle means it's just open continuously. Therefore fuel injected at anything over 100% duty cycle (like 140%) should simply be 100%. if 100% IDC=.15cc=150% IDC, therefore my car should be getting dangerously lean as RPM/boost increases. What do you think, Ray? Thanks, Jeremy Quote Link to comment Share on other sites More sharing options...
rayhall Posted October 26, 2009 Report Share Posted October 26, 2009 Jeremy, The fuel table has a value range from 0 to 100. If you are setting up the table, you should use values less then half this range. I normally try to not put more then 40 in the table on the first start. When I start the engine I adjust the master fuel setting until the air fuel ratio is 14:1 at idle and full engine temperature. Then and only then, do I start tuning the values in the fuel table. The fuel table is a VE (Volumetric Efficiency) table. There is no direct relation to injector time. The table values give the shape of the engine VE, not the actual VE values of the engine. Enabling the AFR Correction will make the values in the fuel table flatter and there will be less chance of exceeding the 100 limit for the table. Quote Link to comment Share on other sites More sharing options...
Guest |306| Posted November 2, 2009 Report Share Posted November 2, 2009 Found a great link regarding injector deadtime/lag values! http://injector-rehab.com/kbse/lag.htm Quote Link to comment Share on other sites More sharing options...
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