jrd Posted April 23, 2007 Share Posted April 23, 2007 OK, as is usually the case I am finding different values for everything and having trouble getting my car running. Acceleration from half throttle is noticably improved now that I have switched from SUs to MS1 - however, I still can not get a decent off idle acceleration - it stumbles and lean backfires on occasion. I actually minimized the off idle lean backfires by adjusting the Acceleration enrichments TPS Threshold = .391 v/s Accel TIme = 0.2s Cold Accel Enrich = 9.0ms Cold Accel Mult = 100% Decel Fuel amount = 50% Acceleration enrichment bins 2 v/s = 5.0 4 v/s = 10.0 8 v/s = 15.0 15 v/s = 25.5 THis is for an NA motor 60mm TB with the stock injectors. Anyone else have values similar to this? Are they reasonable? These are the stock injectors I am assuming they are 240CC/min I have a required fuel = 13ms injector opening time = 1.0 Battery VoltageCoorection = .20 ms/V PWM Current limit = 45% PWM time THreshold = 25.5 ms Are these settings reasonable? Any ideas why I am stumbling off of idle? Thanks, Joe Quote Link to comment Share on other sites More sharing options...
mobythevan Posted April 23, 2007 Share Posted April 23, 2007 Are you the stock injectors you are using low impedance or high impedance? Since it is NA engine I don't want to assume anything. I am just re-iterating this stuff you may know it already: If you use high impedance injectors then follow directions below. If you use low impedance injectors with dropping resistors then follow directions below. If however you are using low impedance with no dropping resistors then follow the procedure in the megamanual to determine the values for PWM% and time threshold. The values you list for those two did not make sense to me, but I have never run in PWM mode, I always disable it according to the quote below because I always use dropping resistors or high impedance injectors. If you use resistors that limit injector current to less than 2 amps, you can disable the PWM mode (by setting PWM% to 100%, and time threshold to 25.4msec) and treat the system as high-impedance. Quote Link to comment Share on other sites More sharing options...
Zmanco Posted April 23, 2007 Share Posted April 23, 2007 What are the pros and cons of using dropping resistors with low impedance injectors vs. going with the PWM method? I'm going to have to make a decision shortly for which path I take with my MS1 v3.0 and stock turbo injectors for my N/A L28. Is the main benefit that it's easier to tune the MS when using the dropping resistors? PS. JRD, hope this isn't too much of a thread hijack - seems relevant to your question. Quote Link to comment Share on other sites More sharing options...
mobythevan Posted April 24, 2007 Share Posted April 24, 2007 This is text from the manual, so it looks like the main concern for dropping resistors is increasing opening time because the current is reduced. Several people reported that resistors do NOT result in significantly longer opening times, or any other troublesome effects, so this is a good solution for many installs. Quote Link to comment Share on other sites More sharing options...
jrd Posted April 24, 2007 Author Share Posted April 24, 2007 Ok, mobythevan was correct, my PWM sttings were way off: It is running much better with the following, but still not perfect - does anyone know what the actual size of the stock NA fuel injectors is? TPS Threshold = .5 v/s Accel TIme = 0.2s Cold Accel Enrich = 9.0ms Cold Accel Mult = 100% Decel Fuel amount = 100% Acceleration enrichment bins 2 v/s = 1.0 4 v/s = 4.0 8 v/s = 8.0 15 v/s = 15.0 I have a required fuel = 14ms injector opening time = 1.3 Battery VoltageCoorection = .20 ms/V PWM Current limit = 85% PWM time THreshold = 1.3 ms No stumble off of idle when warmed up, but still not running well enough for me to call it done. Joe Quote Link to comment Share on other sites More sharing options...
Mack Posted April 24, 2007 Share Posted April 24, 2007 pretty sure stock N/A stuff is only 185cc/min. that could be a problem. Quote Link to comment Share on other sites More sharing options...
z-ya Posted April 24, 2007 Share Posted April 24, 2007 The current limiting resistors are if you don't want to use the PWM feature. They protect the output drivers from sourcing too much current when the PWM current limit is set to 100% (I think is bug in the documentation because when it is set to 100%, there is no current limiting). For the stock low impedance 180cc/min injectors, you should set the PMW variables to: PWM Current limit = 35% PWM time Threshold = 1.5 ms What are you number of squirts set to? Try 3 squirts with simultaneous injector staging. Quote Link to comment Share on other sites More sharing options...
jrd Posted April 24, 2007 Author Share Posted April 24, 2007 So with a 180 cc.min injector I am getting a required fuel for my 2900 cc motor of 18 ms per cylinder - sound right? I am using 6 injections per cycle with simultaneous firing....based on Z-Ya and Mack I have the following settings I have a required fuel = 18ms injector opening time = 1.3 Battery VoltageCoorection = .20 ms/V PWM Current limit = 45% PWM time THreshold = 1.5 ms The car wouldn't run with a PWM Current limit setting of 35%. Right now at 45% it will lean back fire if I step on the gas but at least it idles. Can I just keep upping this until it doesn't backfire or hesitate off idle? Is there another setting that could be causing the issue? Thanks for the help. Joe Quote Link to comment Share on other sites More sharing options...
z-ya Posted April 24, 2007 Share Posted April 24, 2007 I would try 3 squirts, and then use the required fuel value to get the idle smooth. Are you doing fuel only? I can send you a map that should get you close. Send me you email address through PM. Quote Link to comment Share on other sites More sharing options...
jrd Posted April 24, 2007 Author Share Posted April 24, 2007 Z-ya, Yeah I am doing fuel only. I PM'd you my e-mail address. Thanks for all the help. Joe PS any particular reason to do three squirts over six? Quote Link to comment Share on other sites More sharing options...
jrd Posted April 24, 2007 Author Share Posted April 24, 2007 OK, I tried adjusting the required fuel in steps all the way up to 30ms with the PWM at 35% and I just couldn't get it to not hesitate or stall right off of idle. I also noticed that my O2 reading was moving to richer and richer - which is good because this thing has been running lean accept on decel. The best settings so far have been (with three squirts). TPS Threshold = .5 v/s Accel TIme = 0.2s Cold Accel Enrich = 9.0ms Cold Accel Mult = 100% Decel Fuel amount = 100% Acceleration enrichment bins 2 v/s = 1.0 4 v/s = 4.0 8 v/s = 8.0 15 v/s = 15.0 I have a required fuel = 14ms injector opening time = 1.3 Battery VoltageCoorection = .20 ms/V PWM Current limit = 85% PWM time THreshold = 1.3 ms What am I doing wrong? Joe Quote Link to comment Share on other sites More sharing options...
kvansic162 Posted May 1, 2007 Share Posted May 1, 2007 I think Z-ya is on to fixing my problem that has stumped me for months. So far all I did was change my injector PWM time from 1.0 to 1.5 per Z-ya's advice and I couldn't believe the difference. I had that damm stumble every time I switched gears. It seems to be alot better. Now I have to set all the other settings,but only one at a time. Thanks Z-ya....You don't know the service you have done with your test. Quote Link to comment Share on other sites More sharing options...
z-ya Posted May 1, 2007 Share Posted May 1, 2007 Glad to hear some of my work has been useful. A injector PWM time of 1.0ms is too short for the stock injectors. The opening time is around 1.25ms, but can vary depending on the injector. A safe number that should work for all Nissan injectors is 1.5ms. PWM current limit percent should be in the 35 to 40% range. Quote Link to comment Share on other sites More sharing options...
jrd Posted May 1, 2007 Author Share Posted May 1, 2007 Yes, Z-ya has sent me a map that really helped me I am still fooling around a little bit and figuring things out. I am still up at a 70% PWM which is a problem, but I will try a couple of new settings today. I think that the problem has flat out been trying to set too low an idle. We will see I will try somemore today and post the results. Joe Quote Link to comment Share on other sites More sharing options...
jrd Posted May 1, 2007 Author Share Posted May 1, 2007 OK, I finally figured out what I have to do to get down under a 50 PWM. I can't have the PWM time limit turn on before 4ms. This means that I have no PWM until after the pulse lengths get greater than 4ms. I have a required fuel = 18.9ms injector opening time = 1.3 Battery VoltageCorrection = .20 ms/V PWM Current limit = 50% PWM time Threshold = 4 ms I had to up my acceleration bins though Acceleration enrichment bins 2 v/s = 3.0 4 v/s = 4.0 8 v/s = 5.0 15 v/s = 6.0 This seems to be working and the PWM doesn't need to be on at the low injector pulse widths since that is not when they will overheat - it is at the longer pulse lengths that it will matter....heh? Joe Quote Link to comment Share on other sites More sharing options...
Clifton Posted May 2, 2007 Share Posted May 2, 2007 I have to have my opening time pretty low. I idle at 1.4 ms pw so my opening time is 1.0. I had a stumble on on shifts and from decel to part throttle. I bumped my tps threshhold up from 2.0 to 2.5 and it cleared it up. Z-ya, have you checked any Nippon Denso injectors for opening times? currious to know what I should have it at, not that I can raise it much and still adjust idle fuel. Quote Link to comment Share on other sites More sharing options...
z-ya Posted May 2, 2007 Share Posted May 2, 2007 This seems to be working and the PWM doesn't need to be on at the low injector pulse widths since that is not when they will overheat - it is at the longer pulse lengths that it will matter....heh? Joe Joe, Yes, the wider pulse widths will require more power from the injector drivers over a longer period of time. This is why the current limit % is so important. If you choose too high a number, the injectors will draw more current, causing the drivers to overheat at long opening times. 35% equates to around 1A of hold current. Any more than that, and you are just heatingup the injectors and injector drivers. Do you have a good charging system in the car? Quote Link to comment Share on other sites More sharing options...
z-ya Posted May 2, 2007 Share Posted May 2, 2007 Z-ya, have you checked any Nippon Denso injectors for opening times? currious to know what I should have it at, not that I can raise it much and still adjust idle fuel. I measured the opening time on a set of DSM 450cc/min injectors. I think they are Mitsubishi OEM units. The opening time was around 0.9ms. If you have a spare injector, I can measure the opening time for you. I'd like to build a spread sheet of common injectors and their opening times. Quote Link to comment Share on other sites More sharing options...
moerex Posted May 2, 2007 Share Posted May 2, 2007 Z-ya, have you tested a bocsh 42lb injector? Quote Link to comment Share on other sites More sharing options...
Clifton Posted May 2, 2007 Share Posted May 2, 2007 I measured the opening time on a set of DSM 450cc/min injectors. I think they are Mitsubishi OEM units. The opening time was around 0.9ms. If you have a spare injector, I can measure the opening time for you. I'd like to build a spread sheet of common injectors and their opening times. That would be great. I have an extra one that leaks a little at the body. I don't even need it back. I can send it out today or tomarrow. Quote Link to comment Share on other sites More sharing options...
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