280tyler Posted September 18, 2007 Share Posted September 18, 2007 i just recently got my car running on ms1 v3 fuel only and i'm starting to tune it i have some supra 440cc in injectors i bought off ebay i have 2 problems 1. i cant get the car to run with a PWM Time Threshold under 5 it should be between 1 and 2 right? is it bad for the injectors to have it that high? i cant remember if i tried to start it when it was at 25 or whatever it is when you first start so i could have hurt them then 2. i checked the resistance on all of them 4 read 3.5 ohms and 2 read 5.8 ohms is this bad i'm asking because it is idling kinda rough and stumbles when i give it some throttle thanks Quote Link to comment Share on other sites More sharing options...
z-ya Posted September 18, 2007 Share Posted September 18, 2007 Are they high or low impedance? If they are high impedance, then you set the PWM controls as if you had resistors in there (PWM limit = 100%, PWM time = 25). Quote Link to comment Share on other sites More sharing options...
ktm Posted September 18, 2007 Share Posted September 18, 2007 Supra 7MGTE injectors are low impedence. Quote Link to comment Share on other sites More sharing options...
280tyler Posted September 18, 2007 Author Share Posted September 18, 2007 yes there low that is why i confused a PWM Time Threshold of 5 is to high for low impedence injectors isn't it Quote Link to comment Share on other sites More sharing options...
WizardBlack Posted September 22, 2007 Share Posted September 22, 2007 2. i checked the resistance on all of them 4 read 3.5 ohms and 2 read 5.8 ohms is this bad Yes. Get them cleaned and tested by a fuel injector shop such as rceng.com. Pull your plugs; you probably have a pretty significant cylinder to cylinder fuel imbalance. Quote Link to comment Share on other sites More sharing options...
z-ya Posted September 22, 2007 Share Posted September 22, 2007 Duh, I should have read your post a little better. My bad.... Low Z injectors are usually in the 2-2.8 Ohm range. Maybe the Supra injectors are a little different. But two are way out of spec (or 4 are depending on what nominal impedance should be for those injectors). Get them cleaned and flow tested first, Witchunter Performance can do your set for around $100. If they all come back flowing about the same, then group the injectors so that each of the two groups of three have two 3.5Ohm, and one 5.8Ohm in the group. This will balance the impedance between the two output drivers. If you have the two 5.8Ohm, and one 3.5Ohm injector on a output driver, this could be causing your problem. The PWM controls control both drivers together, so the impedance between the banks should be close to the same. Also, be sure that you are using a good quality Ohm meter, cheap ones are not so accurate at low DC resistances. Quote Link to comment Share on other sites More sharing options...
280tyler Posted September 23, 2007 Author Share Posted September 23, 2007 i just bought some new ones i got 6 450cc rebuilt and tested dsm injectors for just about as much as a local shop wants to rebuild my supras hopefully that takes care of some of my bugs thanks for the help Quote Link to comment Share on other sites More sharing options...
ktm Posted September 27, 2007 Share Posted September 27, 2007 FYI, Mr. Injector on Ebay will clean, test, and bench flow 6 injectors for $80 shipped. He has very fast turnaround and great communication. Quote Link to comment Share on other sites More sharing options...
280tyler Posted September 30, 2007 Author Share Posted September 30, 2007 well i put my new injectors in today but i'm still having some problems they are 450cc dsm injectors and when i put the constancies off the sticky it barely runs and will not rev up unless i open the throttle very slow if i open it kinda fast it just leas out and dies if i raise my PWM Time Threshold up to 4 it is much better it hesitates but that might go away when i tune it more is it ok to run it with a PWM Time Threshold of 4? could there be a problem with my injector drive? this is just like what was happening with my other injectors thanks Quote Link to comment Share on other sites More sharing options...
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