adam87S4

Hey, I am a new member on the forum and looking for some assistance. I have an S4 GXL which I am converting to TII and going to be running a megasquirt2. I am at the point of already being done building the ECU with the zeal board and now testing on tunerstudio. I have the latest ms2extra firmware 3.2.4....I think that it anyways...
My problem (which I have repeatedly seen on this forum) is that I cant seem to get a RPM signal on tunerstudio when testing the megasquirt with the jimstim. I have tried using the wheel selector as the jimstim site describes for a 24/2 trigger wheel. Have adjusted the pots fully counter-clockwise and all, and jumped the primary tach on the stim for VR sensor. Have tried both 12 and 5 volt pullups on the stim aswell. Nothing has even hinted of working so far. I should include that all other inputs from the stim are working correctly. When building the mainboard I jumped Tachselect to vrin and tsel to VRout as described on the DIY site. Have read aaron cakes and diyautotunes sites more times then I can count before, during and after the build process, keeping in mind the slight differences in setups for each, not that there are many...Also when building the squirt using instructions on the megamanual site for v3 assembly in step 50 I assembled according to 50 b not a. Would that have anything to do with how the jimstim inputs work... if there is anything I have missed just ask and I can clarify.

Thanks, Adam

adam87S4

nevermind about this thread lol, I did a whole bunch of reading since lots of people have similar issues and found that using a .01uf cap inline with the 2nd trigger might work. Well it did, the rpm shot right up on tunerstudio, works perfectly now time to finish the manual labour now

ben@diyautotune

The JimStim is not capable of producing a true zero-crossing sin wave, so it doesn't trigger the LM1815's in the Zeal board correctly. You should be able to check other sensor inputs such as TPS, AIT, and CLT... But unfortunately not RPM input.

However, you can spin your CAS on a drill with output hooked into the JimStim (with the RPM pots both at full counterclockwise) to test the RPM input.