boardkid280z Posted July 31, 2006 Share Posted July 31, 2006 I bought my V3 board kit at DIYauto.com and am running all the standard hardware that comes with the kit, I also setup the board to directly fire the coil. I did not set up a flyback board for my injectors, nor did I wire in any resistors for the low impedance injectors from an '81 Turbo ZX. From what I understood when installing MS, the V3 board did not require a flyback board and will directly run the injectors without a need for reducing PWM <100%. So I have the injector opening time set to 1.0ms, PWM Current Limit (%) is set to 100% and PWM Time Threshold is set to 25.4ms (I think that's the default). Do these settings sound right for the V3 board and MS1 I have? A problem that developed about 2 weeks ago is that suddenly the car would not stay running and I had not changed any MS settings. To get the car running, I had to UP the "req fuel" (ms) setting from the 12ms it was at for the 270cc injectors to 23ms (about 135cc injectors). So basically I had to double the fuel. It ran fine like that, took a little tweaking again to get everything set right, but since then the fuel req has been 23ms instead of 12 like it used to be. Any idea what might have caused this?? I am completely stumped, and a little worried that there is still a problem somewhere. Any suggestions are welcome! Quote Link to comment Share on other sites More sharing options...
Metro Posted August 1, 2006 Share Posted August 1, 2006 You don't need the addon flyback board like with v2.2 because it's built into the v3 circuitry already (if you opted for the parts). High impedance injectors don't need pulse width modulation - they need full power, so you would set it to 100% and pwm time threshold to 25.4ms. If you run at 100% with low impedance injectors and no resistors, you will fry your injectors. From the MS manual: If you are running high-impedance injectors (greater than 10 Ohms)' date=' then set the: * PWM Time Threshold to 25.4 msec, and the * PWM Current Limit (%) to 100%. If you have low impedance injectors (less than 4 Ohms), set the: * PWM Time Threshold to 1.0 msec, and * PWM Current Limit to 75%(30% if you have installed the 'Flyback Board' daughter card). [/quote'] In case you didn't know, the stock L28et injectors are low impedance - around 2.8-3 Ohms. With my stock L28et injectors I found to the sweet spot to be around 45% for PWM and 1.0ms for the opening time. Quote Link to comment Share on other sites More sharing options...
boardkid280z Posted August 1, 2006 Author Share Posted August 1, 2006 Well, that stinks... I do have the stock turbo injectors, and yes I was aware that they are low impedance. I guess I just didn't read the manual thoroughly enough to find all the details explained. Things are a little confusing with the differences between the V2.2 and older and the V3 boards, so I thought had it set right. Thanks for the clear explanation and reference in your reply. It still seems to be running OK with the req fuel adjustment I had to make... is it possible that the car will still run with fried injectors with changes like that? Or is that probably something unrelated? What would the symptoms be of fried injectors, would the injector solenoid freeze up and let a constant amount of fuel through, be it none, or a lot? or what? If I did fry my injectors, this will be a good excuse to find some bigger cc injectors Quote Link to comment Share on other sites More sharing options...
mobythevan Posted August 1, 2006 Share Posted August 1, 2006 It still seems to be running OK with the req fuel adjustment I had to make... is it possible that the car will still run with fried injectors with changes like that? Or is that probably something unrelated? I would go ahead and set it up correctly like metro shows, then put required fuel back to where it should be. See if it will idle and then listen to all 6 injectors with a stethoscope or something else, and see if they all sound like they are working. Quote Link to comment Share on other sites More sharing options...
boardkid280z Posted August 2, 2006 Author Share Posted August 2, 2006 I made the changes as suggested by metro and changed the "req fuel" parameter back to what it should be. It would not stay running like that. I changed "req fuel" back up to 23-24 and it will run like that. But, the first time I got on it, it blew the 2amp MS fuse. I replaced the fuse, and blew it again. I have been driving carefully since then. But now it stutters really bad randomly, seems like it is in 2nd gear when I'm slowly accelerating. When I accelerate faster it seems to run fine... I can't tell what's causing it. I also disconnected all the injectors individually, and everytime I do, the engine runs a little rougher, then smooths out when I reconnect them. That happens for each injector, not as noticeably with inj 1 and 3, so I will check them again later. But I think they are all working. Any other suggestions?!? Quote Link to comment Share on other sites More sharing options...
boardkid280z Posted August 4, 2006 Author Share Posted August 4, 2006 As an update to my last post, I think when it was stuttering MS was resetting, because I had my laptop hooked up and I heard the sound MS makes when it connects two of the times it stuttered. Since my last post, I haven't had any problems, and have slowly been getting on it more to see if it will blow the fuse and it hasn't yet. I really need a wideband O2 sensor, cuz going off the narrow band to see how my fuel is is not accurate. I will check the plugs tonight and see how they all compare. Quote Link to comment Share on other sites More sharing options...
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