24/2 nippodenso cas

[drewrey2004]

Ok right now I'm running the 2.1.0 beta for a 2nd generation Mazda Rx-7 Turbo. I recently built the dual vr board and checked to see if everything was working with the factory cas. Everything seemed ok i spun it and it synced up. Now maybe a week later i read that a .01uF cap should replace C4 on the board so that there would be no problems reading rpm. I changed it with a square cap I had laying around that was supposedly a .01uF rated cap. After I changed the cap I wanted to make sure that it still was ok before I install it. It read wild rpm for a short period of time and showed a congif error on the bottom of megatune then it just stopped working. I tried checking to see if maybe megatune had gotten corrupted so i reflashed and reconfigured my settings and still nothing. I also built the other side of the board thinking my lm1815 was bad and it still wont sync up. Is it possible I burnt out the output of the 2nd VR conditioner circuit going into the processor itself?

[racingmini_mtl]

I doubt very much you burned something. And by the way, the 0.01uF cap is only needed for MS1. For MS2/extra, you can use the 0.001uF cap.

There are 2 things you can try. The first thing would be to simply ground pin 14 of the LM1815 which will cause the output to be proportional to the RPM instead of a constant pulse width. You can do that by simply soldering a jumper across C4 (or C8 if you're using the second circuit). The second thing you can try out is to reinstall a 0.001uF if you have one available.

Jean

[drewrey2004]

I put the .0001 cap back in and still nothing. What's weird is that when using the jimstim in dual wheel mode (24/2) I get a waveform signal at the 2nd trigger pin but when I connect it to VRin the signal goes flat.

[racingmini_mtl]

Don't forget to put the 12V pull up jumper on the JimStim for the 2nd tach signal. Also, to trigger the LM1815 from the JimStim you need to put a cap in series with the tach signal because it needs zero crossings.

Jean

[drewrey2004]

I tried the 12v pullup for it and I still don't get a wave signal. If I put the cap on the primary signal it crosses zero but I get nothing from the 2nd trigger pin when i put the cap on it.

[racingmini_mtl]

Then there is a problem because you should get a signal with the cap and the 12V pullup and it should have zero crossings. How are you checking if you have a signal? Are you using a scope?

Jean

[drewrey2004]

Yes I'm using a scope. Also I just checked it with the factory cas and I'm still getting nothing. If I change the trigger settings to Basic Trigger it works but I'm getting nothing with Toothed Wheel.

[racingmini_mtl]

Have you set the Spark A output to D14?

[drewrey2004]

Yes I did. Would it be worth trying to switch to 1.0.2 and switch the 2nd VRin to JP4?

[drewrey2004]

Now that you mention spark output, I did notice that when I got the config error on the bottom of megatune, I checked my settings and the I saw JS10 in the Spark A output box. Will hurt anything in the hardware?

[racingmini_mtl]

I don't think so but it will certainly screw up with timing since it's both used as 2nd tach input and spark output. I haven't looked what exactly will happen in the code but it can't help things.

Jean

[drewrey2004]

Well is there a way to fix this? I really want to keep this new code. Also I'm having trouble downloading 1.0.2 firmware. I'm getting a command error in the v2.00 downloader. I think it's 0=Ex1

[racingmini_mtl]

You just need to use D14 for spark A and JS10 for the 2nd tach trigger and configure your settings accordingly.

You can't use the downloader with Ms2/extra. You have to use the batch file that comes with the MS2/extra release. But you shouldn't have to go back to the 1.0.2 firmware.

Jean

[drewrey2004]

I have everything set in megatune the way I should. Here's my msqfile

ms2extra-13brotaryturbo.msq

[drewrey2004]

Hey Jean I don't know if you read my post in the ms2extra section but I noticed that I'm getting 5V off the IGN port with it disconneted from the duel VR board. Is this supposed to be that way? I don't understand why it only reads rpm wired backwards?