nienberg.11 Posted September 12, 2007 Share Posted September 12, 2007 Guys, I've just installed EDIS and everything seemed to be working perfectly until I tried to drive the car. Before I even got out of the driveway it started bucking and surging. I locked the ignition at 15 BTDC, thinking that ignition changes were the cause. This didn't help, nor did disconnecting the SAW input and running in limp-home mode. I noticed that the Megasquirt's tach readings went wild any time I got near 2500 rpm, and realized that this must be the cause of the roughness. The car hasn't had this issue in the past, and I suspect that the changes I made to the tach input circuit for EDIS are where the problem lies. I've double checked my wiring and it seems to check out. Perhaps this circuit is more susceptible to electrical noise. If anyone has a clue on this, let me know. Here are the instructions from msextra.com that I followed when changing the MS mainboard: Input mods: Output mods: Quote Link to comment Share on other sites More sharing options...
datman Posted September 12, 2007 Share Posted September 12, 2007 what type injectors are you running? I had this problem with my low imp injectors...Running a dedicated +12v feed to the power pins of both the injector drive transistors solved the problem. The mod is listed on the MS forum under noise mods. Also, have you used shielded cable for pip and saw? Quote Link to comment Share on other sites More sharing options...
nienberg.11 Posted September 12, 2007 Author Share Posted September 12, 2007 I'm running stock 280zxt injectors, and yes the PIP and SAW as well as the VR signal are all sheilded. I hadn't considered that the injector drivers might be the issue. Did yours start doing this after you added EDIS or some other form of ignition control? Also, did it wig out around the same RPM? EDIT: -I'm running the zxt injectors as low impedence (no resistor packs) -After 30 minutes of searching I haven't been able to find this mods page. If you could help me out with a link, I'd appreciate it. Quote Link to comment Share on other sites More sharing options...
HizAndHerz Posted September 12, 2007 Share Posted September 12, 2007 Here is a post at msefi.com that has the mod instructions and pictures in it: http://msefi.com/viewtopic.php?p=167375 You have to be logged in over there to get at the attached files. Quote Link to comment Share on other sites More sharing options...
nienberg.11 Posted September 13, 2007 Author Share Posted September 13, 2007 It turns out that it had nothing to do with the injector drivers. The tach input circuit that msextra.com instructed me to build was the issue. I kept the SAW output mods but undid their input mods and went back to the standard hall input circuit. This cleared the issue up completely. Quote Link to comment Share on other sites More sharing options...
datman Posted September 13, 2007 Share Posted September 13, 2007 can you post the mods here so I can double check mine is correct. Glad to hear you sorted the problem. Quote Link to comment Share on other sites More sharing options...
nienberg.11 Posted September 13, 2007 Author Share Posted September 13, 2007 Here's what I did: I left all of msextra's EDIS output mods in place (shown above). The saw didn't work right without them. I then compared msextra's EDIS output mods with the hall circuit assembly, step 50a from the MS v3 assembly guide at megamanual.com/ms2/v3assemble.htm That led me to these steps to revert to the normal Hall input from msextra's circuit: -Leave C30 out and remove the jumper between it and S12C -Jumper C1 and C2 -Install R12 -Remove the jumper between TACHSELECT and XG1 -Jumper XG1 to XG2 -Jumper TACHSELECT to OPTOIN -Jumper TSEL to OPTO OUT -Install U3 -Install C11 -Install R13 This left me with a Hall tach input on DB37 pin 24 and a SAW output from LED17 through DB37 pin 36. I'm considering adding in C12 for noise reduction as well. I'm still getting lone tach spikes here and there. Quote Link to comment Share on other sites More sharing options...
datman Posted September 14, 2007 Share Posted September 14, 2007 Thnaks Nienburg, may also help some future Megasquirters. Quote Link to comment Share on other sites More sharing options...
nienberg.11 Posted December 27, 2007 Author Share Posted December 27, 2007 DatMan, The link that HizandHerz posted isn't working anymore, and now I'm looking into that noise mod again. The fix that I used didn't completely solve my problems and I still have some roughness and voltage spikes. If you could point me toward the injector noise mod, I'd appreciate it. Quote Link to comment Share on other sites More sharing options...
datman Posted December 27, 2007 Share Posted December 27, 2007 http://65.35.225.254:56789/Spike_Mod/Noise.rtf http://65.35.225.254:56789/Spike_Mod/Noise_Mod_1_.JPG http://65.35.225.254:56789/Spike_Mod/Noise_Mod_2_.JPG http://65.35.225.254:56789/Spike_Mod/Noise_Mod_3_.JPG Here you go!! Quote Link to comment Share on other sites More sharing options...
datman Posted December 27, 2007 Share Posted December 27, 2007 Oh , don't forget to set MS EDIS to rising edge not falling edge Quote Link to comment Share on other sites More sharing options...
nienberg.11 Posted December 27, 2007 Author Share Posted December 27, 2007 Thanks again Datman. I looked for the rising/falling edge setting and couldn't find it anywhere in Megatune. I'm thinking that might be something that shows up with Megasquirt II and not MSnSE. While I'm posting, here's a graph of my RPM signal from a datalog I took last night: Quote Link to comment Share on other sites More sharing options...
Matt Cramer Posted December 27, 2007 Share Posted December 27, 2007 Thanks again Datman. I looked for the rising/falling edge setting and couldn't find it anywhere in Megatune. I'm thinking that might be something that shows up with Megasquirt II and not MSnSE. That's correct. It's an MS-II setting. A complete data log will be helpful at spotting noise sources, since you can check several different variables at the same time to see if the noise is confined to one input or not. Quote Link to comment Share on other sites More sharing options...
nienberg.11 Posted December 28, 2007 Author Share Posted December 28, 2007 I did the flyback mod to Q9 and Q12, and added a noise eliminator to the MS power source. The car runs excellently now with no stumbling or lurching. I re-logged the same route as before. Here are the results: As you can see, it's still not perfect but it's improved enough that I'm not going to worry about it. It seemed like those two lone spikes must have been disregarded by the MS, because there was no roughness of any kind during that run, or later when I took the car on a longer drive. Quote Link to comment Share on other sites More sharing options...
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