383 240z Posted April 30, 2007 Share Posted April 30, 2007 OK Here goes I'm using a V-3 board and MT version 2.6, Im tring to get the VR signal to be "seen" by MS. I have the VR wired to pin 24 (the signal line of a shelied cable I got from DIY-Autotune) and pins 6&7 (the sheild of same cable). I've tried swaping the leads on the VR with no change. I've tested the VR with my DVOM and I'm getting a signal thru the harness and up to the DB-37 on the MS. I've checked that the pots R-56 and R-52 are turned fully CCW as per build step 51 g. Also from step 52, I have the jumpers VRIN to the TACHSELECT and TSEL to the VROUT. I have the settings in MT set to going high inverted. I'm pulling my hair out here!!! I been fighting with this for a week now!! Keith Quote Link to comment Share on other sites More sharing options...
Matt Cramer Posted April 30, 2007 Share Posted April 30, 2007 There's a couple things to check here. First, if you've got a Stimulator, I recommend testing the Megasquirt out on it and letting us know the results. Second, are you using the wheel decoder? Quote Link to comment Share on other sites More sharing options...
383 240z Posted April 30, 2007 Author Share Posted April 30, 2007 Sorry about that Yes it works great on the stim V2.2 As to the 2nd part of your reply what is a wheel decoder? I have a VR mounted inside my dizzy. I removed the rest of the internals and locked out the vac advance. so the only thing that can change the spark timing is me, using the MT of course. Keith Quote Link to comment Share on other sites More sharing options...
383 240z Posted April 30, 2007 Author Share Posted April 30, 2007 I just left the shop I double checked the rpm input on the stim, it is a good solid signal, I can go from 0 rpm, slowly input a >300 rpm crank signal, and a full running signal. I'm not sure if I mentioned it but I also put mt DVOM on the AC scale and got a signal when I crank the engine, I probed the DB-37 connector itself to check all the wiring from the VR to the MS. Keith Quote Link to comment Share on other sites More sharing options...
mpcapps Posted April 30, 2007 Share Posted April 30, 2007 What is the maximum RPM that you can get MS to read using the stim? if it's low (like 1300-1400 max) i suggest reloading the firmware onto the chip (and making sure you have the latest ini file for megatune). I had an issue where MS wouldn't see RPM from my VR sensor, but would on the stim. when i finally got the car started (reading RPM directly off the coil), RPM would register 1/10 what it actually was. Reloading the firmware fixed this, and from what i've read is the only way to fix RPM reading problems like this. Quote Link to comment Share on other sites More sharing options...
383 240z Posted April 30, 2007 Author Share Posted April 30, 2007 I'm not sure but I'm sure it was over 5K. I can check later tonight. Keith Quote Link to comment Share on other sites More sharing options...
383 240z Posted May 1, 2007 Author Share Posted May 1, 2007 Last night I was working on this, I remembered Matt's question about the wheel decoder, In my sleep deprived mind I thought Trigger wheel (kinda close??) and I changed the values, I set Trigger wheel teeth to 6 (it is a six cylinder) missing teeth 0 (they are all there) Skip teeth 0 (count them all why not) Delay teeth (I'd like all the rpm right now!!) and I get no responce on the stim, I'm going to change them back now. Keith Quote Link to comment Share on other sites More sharing options...
Matt Cramer Posted May 1, 2007 Share Posted May 1, 2007 You should have the trigger wheel set to zero when you aren't using a wheel decoder. I've seen quite a few cases where it was left on by mistake, and this will give you a zero RPM reading. Quote Link to comment Share on other sites More sharing options...
383 240z Posted May 1, 2007 Author Share Posted May 1, 2007 Ok I put the wheel encoders back to the pre-sets (defaults?) I now have rpm input on the stim. when I turn it all te way up it goes to aprox. 9100 rpm. I had spent some time with a friend (who knows more about this than me) do some trouble shooting. His theroy is, the signal is getting into the processor but the output (I forget what line I was tapped into) is not a clean digital wave form. what I was getting on my meter is a solid 5V signal, not an ON/OFF signal. So he was thinking that the tunable pots are where I need to focus. I suspect he will be dragging his O-Scope over this Sat. for further diag. Keith Quote Link to comment Share on other sites More sharing options...
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