tolerate Posted August 11, 2014 Share Posted August 11, 2014 Hi All, I've posted this before, but i've tested this out on the dyno. the tuner had no idea what the problem could be. Problem: No matter how much fuel we put in the VE table, the AFR keeps leaning out around 3500 rpm. Can you MSnS Yodas figure out what's going on? Things we've checked: - Fuel pressure during dyno run: correct - Fuel line/filters cleaned/exchanged - Spark advance timing: checked with light - AFR calibraiton (its a dyno) I've put the dyno run datalogs and the latest tune. the last tune corresponds with the latest datalog. Car Specs- - 440cc/min low z supra injectors - L28ET from 1982 ZXT - MSnS 1 v3.0 (reflashed, problems still persist) - LC-2 wideband -1982 280zxt dizzy - MSD blaster 2 igntion coil w/ inline resistor (getting hot blue spark) Car extras: - manual boost controller - front mounted intercooler - garrett turbo thing, i think 57 trim attachments.zip Quote Link to comment Share on other sites More sharing options...
tolerate Posted August 12, 2014 Author Share Posted August 12, 2014 Could this be a symptom of flyback failure, even though I have the blue v3.0 PCB? http://www.megamanual.com/v22manual/minj.htm for more information about flyback failure, the symptoms outlined match my car's problems. I didn't build the MS unit so I cannot confirm that. I will at the board for burnt-ness: .When the flyback fails, sometimes Q1 (the TIP32 on the bottom of the PCB) looks pretty rough, all burnt, etc. However sometimes it looks fine If Q1 (on the bottom of the board) does look burnt however, this is a sure sign of a flyback failure. Quote Link to comment Share on other sites More sharing options...
Metro Posted August 12, 2014 Share Posted August 12, 2014 You need to be more specific in what you're trying to show. From what I've skimmed in your log files, everything looks relatively ok. I'm assuming the problem logs are the short log files of RPM pulls, are showing very rich around 10:1 which corresponds to to VE table going into the 200+ range. With 450cc injectors, I don't believe I ever went higher than 170 in the VE table at 15psi on the stock turbo. Quote Link to comment Share on other sites More sharing options...
tolerate Posted August 12, 2014 Author Share Posted August 12, 2014 Hi Metro, Thanks for taking a look. I wouldn't trust the AFR readings, he used the O2 sensor for his dyno computer, disconnecting my O2 sensor from the LC-2 in the process. The problem is that I lose power after 4000 rpm, it stalls out and dies. I remember seeing the AFR stay around the 12-13 range throughout the pulls. I Know the VE table isn't right either. I just wanted to know if anyone with diagnostic experience has seen this before, is this a classic sign of anything? But I can't figure out why my engine isn't getting the fuel it needs. I've tested the MSnS unit with the stimulator and everything responded as I expected. I just test drove it again, and its trying to stall out at 3000 rpm. Maybe relevant: Lights and blinker weren't working when it arrived in the dyno, and I had to replace the megasquirt main relay. After I got it back, The voltmeter and lights are working again, hazards aren't still (figure its the flasher relay). By the voltmeter not working I mean the needle didn't go past 4 volts, but the multimeter reading showed >13 V. Quote Link to comment Share on other sites More sharing options...
Metro Posted August 12, 2014 Share Posted August 12, 2014 When I had a problem with leaning out a specific RPMs, it was due to dirty injectors. I sent them off to be cleaned by witch hunter performance and it fixed the problem. If you can, swap out your injectors for another set and see if that helps. Quote Link to comment Share on other sites More sharing options...
tolerate Posted August 12, 2014 Author Share Posted August 12, 2014 When I had a problem with leaning out a specific RPMs, it was due to dirty injectors. I sent them off to be cleaned by witch hunter performance and it fixed the problem. If you can, swap out your injectors for another set and see if that helps. I sent them off to be cleaned by witchhunter December 2013, (I'm also running a filter between the pump and tank and a filter between pump and rail) and I don't have a spare set of injectors on me. I will try installing high impedance resistors first and double checking grounds. If there's a problem with the PWM flyback, then high impedance should fix that right? Quote Link to comment Share on other sites More sharing options...
NewZed Posted August 12, 2014 Share Posted August 12, 2014 I may be way off base here, but have you verified that the injectors are supposed to be open long enough to satisfy the air volume? In other words, does pulse width increase consistently as you pass through that lean zone. I'm not familiar with all of the MS variations but I copied a Megatune screenshot that shows what I mean. The pulse width should increase pretty closely with RPM, assuming a constant throttle setting. At least, it shouldn't stop increasing or go backward. Might be worth a look. I assume the Megatune data is what's supposed to happen, not what really happens. In other words, it's showing what MS is telling the injectors to do. I assume the flyback problem is the injectors not staying open as long as they're supposed to. There may even be a way to plot pulse width versus RPM, in a program like Excel, to look at the relationship. Quote Link to comment Share on other sites More sharing options...
winstonusmc Posted August 12, 2014 Share Posted August 12, 2014 Check the voltage to the injectors as the RPMs go up. I had a problem on my low impedance 444cc injectors in that the resistor was wired wrong and the injectors weren't getting enough voltage. Quote Link to comment Share on other sites More sharing options...
tolerate Posted August 13, 2014 Author Share Posted August 13, 2014 (edited) Check the voltage to the injectors as the RPMs go up. I had a problem on my low impedance 444cc injectors in that the resistor was wired wrong and the injectors weren't getting enough voltage. Hi Winston, was the injector internals wired wrong? I haven't added dropping resistors yet (they'll be here Next week), is that what you're referring to? I'll take a look at the voltage (I guess i should be seeing flashes of 12?) I may be way off base here, but have you verified that the injectors are supposed to be open long enough to satisfy the air volume? In other words, does pulse width increase consistently as you pass through that lean zone. I'm not familiar with all of the MS variations but I copied a Megatune screenshot that shows what I mean. The pulse width should increase pretty closely with RPM, assuming a constant throttle setting. At least, it shouldn't stop increasing or go backward. Might be worth a look. I assume the Megatune data is what's supposed to happen, not what really happens. In other words, it's showing what MS is telling the injectors to do. I assume the flyback problem is the injectors not staying open as long as they're supposed to. There may even be a way to plot pulse width versus RPM, in a program like Excel, to look at the relationship. In regards to the RPM and PW relationship, I noticed theres a lag between TP and PW, but it seems to be at wide open throttle. small TP values correspond well with PW. I attached snapshots and also a snapshot of a noisy TP signal messing with my spark settings. Is it really caused by the noisy TP? http://imgur.com/a/QarWB edit: forgot to mention we didn't set accel enrich for the WOT pulls Edited August 13, 2014 by tolerate Quote Link to comment Share on other sites More sharing options...
tolerate Posted August 13, 2014 Author Share Posted August 13, 2014 I ordered some 5.6 ohm 25 watt resistors http://www.radioshack.com/product/index.jsp?productId=12566163 for the low z supra injectors online, I don't have any local suppliers. Looks like it should be here next week. I'll be checking on the sensor grounds and other stuff until the resistors get here. Quote Link to comment Share on other sites More sharing options...
winstonusmc Posted August 13, 2014 Share Posted August 13, 2014 Junk yard Honda resistors work well for the injectors. I use a Nissan resistor from a GTR. If you check the feed voltage it should be steady battery voltage, regardless of RPM. Quote Link to comment Share on other sites More sharing options...
tolerate Posted August 14, 2014 Author Share Posted August 14, 2014 Junk yard Honda resistors work well for the injectors. I use a Nissan resistor from a GTR. If you check the feed voltage it should be steady battery voltage, regardless of RPM. ok that makes sense bc MS is grounding them, after I install serial resistors on the pos of each injector (6 total) the PWM settings will change to High impedance settings? the resistors will be here tomorrow so I think it should be ok. I'll break out the solder and check my grounds while i'm doing that. Quote Link to comment Share on other sites More sharing options...
winstonusmc Posted August 14, 2014 Share Posted August 14, 2014 Yes, it will be normal high impedance settings. mine are running off the MS3X board. I would like to do a peak and hold controller, but I think it would be better to just do different injectors. Quote Link to comment Share on other sites More sharing options...
tolerate Posted August 15, 2014 Author Share Posted August 15, 2014 So I thought more about this and realized the Batt V noise is causing the PWM to act up. The batt v is ranging from 7-16 V. The batt V correction will be crazy. (check out the imgur link, the top three pictures illustrate this). This seems to come up on MSnS systems running Low impedance injectors. more info here http://www.msextra.com/forums/viewtopic.php?f=101&t=28178&start=20. I'll get a cheap capacitor and see what happens. update ya'll over the weekend. Quote Link to comment Share on other sites More sharing options...
tolerate Posted August 16, 2014 Author Share Posted August 16, 2014 I received the resistors today, but decided to try the capacitor thing first.. less soldering. I live on a hill and before the car would stall out near the top. She roared in today after the capacitor in the bootloader thing. I'll go for a test drive probably Sunday. Whats the consensus. Keep the low Z injectors or go high Z anyway? Quote Link to comment Share on other sites More sharing options...
winstonusmc Posted August 16, 2014 Share Posted August 16, 2014 There is a reason they use them in performance situations. They seem to have been a better way in the old days to have a larger flow without having an excessive dead time. Now days, with newer technology, we can have larger flow injectors without a sacrifice in lower pulse widths. Quote Link to comment Share on other sites More sharing options...
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