lukec53

First off I want to say I know that there are many "no rpm signal" threads already out there, and I HAVE read 99% if not all, tried all the solutions, and have not been able to get this thing going.

So here's MY situation. I've constructed my megasquirt 2 V3 according to aaroncake's website on a static safe work space (with static wrist strap). I successfully installed MSII/extra 3.2.1 release, and set it up with all the settings on Aaron's site, except for the changes he posted in the sticky thread, which I have also burned to the ECU.
I built my second VR conditioner circuit in the proto area as shown on aaron's write-up. I have attached a schematic/drawing I drew of my exact proto area. (the connections in red aren't any different than the others, my pen just died)

I have the following jumpers installed:
TACHSELECT -----> VRIN
TSEL -------> VROUTINV
Tried with and without jumper over leads of c32 to "remove" it
Have tried with and without jumper over D2 for stim use (which did work for RPM signal when I had the board set up for the stock firmware, and had the stock firmware installed)

I have tried having both of my POT's turned all the way CCW, and having one CCW and the other CW as the assembly instructions suggest, neither work. (Just to note, my POT's don't click, nor can I feel anything when I get to the ends. I had to set them by watching my multimeter untill the resistance stopped changing, aka its at it's end)
I have triple checked my CAS wiring, tested for continuity, used shielded wire, and everything there checks out good there. I'm also sure both of my CAS's work.

When I power it up via my stim, I see the fuel pump LED come on for a second, then shut off as it should. But here's where it starts to get weird. From the time it gets power, the "FIDLE" LED is always on, as well as all 3 LED's on the squirt itself. The two injector lights never come on. All of the sensors show their proper readings live, except the rpm, which shows nothing.

When I power up in my car, I have 11.9 Volts, I hear the fuel pump come on for a second then shut off, all of my sensors show what they should and are live, but when I crank the engine, I see no rpm. I tried using the "tooth logger" and it (kind of) worked last week when I tried (showed a couple sharp spikes, then some very very short pulses that looked like square waves), but after playing with the settings I have not been able to get it to work again, and the one log I did get didn't save.

I have now hooked up my spare CAS directly to the corresponding pins (2,3,4,24) on my stim to try to troubleshoot this, still no rpm or tooth logger.

I don't have access to an oscilloscope.

Sorry for the giant writeup, but I think that should be most of the info you guys need, if something's missing, let me know. I've also attached my MSQ file, and a picture to show happens when hooked up to the stim.

lukec53

oh right, before someone asks, I'm currently using tunerstudio

lukec53

As well as being open to ANY suggestions on what to try, I also have two specific questions I forgot to ask.

First: Was jumpering c32 just a stupid idea all together? It occurred to me as I was writing this that jumpering c32 may not have been the right thing to do, because I think that and a resistor are connected in parallel not in series. This means the proper thing to do would have been to literally just remove it?

Second: Could somebody please look over how I constructed my second VR circuit and let me know whether it's done right? I know I soldered the main circuit itself properly, I was just a little confused on the instructions to hook up the SPR2 wire.
on Aaroncake's write-up it says "Connect SPR2 (pin 4 of the DB37) to the ground point of the LM1815 circuit with a bit of hookup wire." I was a little confused as to whether or not I was supposed to have the "ground point" literally connected to the "GND" of the proto area, or if he was just referring to "ground" as the other lead of the sensor (SPR2)

lukec53

Update:
After reading more about the VR circuit itself, I think I have a much better understanding of it now.
I came to the conclusion that jumpering over c32 was definetly not the proper thing to do, so I have removed it completely now to try to aid my signal, but that did not fix my issue.
I also realize now that once I'm jumpered to select my VR circuit, D2 really doesn't do anything so that jumper doesn't matter.

I've attached pictures of all of my relevant settings.

Does anyone have any suggestions for me? I'm stumped!

Do I need to have to input a setting that tells the 'squirt where to find the second VR signal? Or does it automatically know where it is when you select "Dual Wheel"?

muythaibxr

If you're trying to use the stim, you need to make sure it's set to output 12 volts to the MS on the primary tach signal.

You have to have a secondary tach signal configured as well and going into your lm1815 extra circuit.

Your settings look fine.


Ken

lukec53

I figured the megastim (not Jim stim) wasn't able to output a proper signal to the VR circuit because the signal doesn't cross zero? Is there a way to modify the stim to create the proper signal? (If there is a way, please tell me how )
To get around this limitation, I took my extra CAS and literally soldered four wires on my megastim's db37, so that the 'squirt would receive the same signal as it would if it were in the car

lukec53

After trying a bunch of fixes and having no luck with my stim, I hooked it back up to the car today and actually got something!
Now obviously there's still something wrong with the signal I'm getting as I still have no RPM, but I'm hoping this, with some help you guys, can at least give me some insight to what my problem is.
I still have no RPM, no tooth logger, no trigger logger. BUT this time I DID get composite logger to register something when I spun the CAS!
I've attached a log file from composite logger, as well as a picture of what it showed on my screen.

lukec53

Here is a better log.
This time instead of spinning the cas with my hand, I span it with a drill. I started off going slow, then increased the speed every time I saw tunerstudio refresh (little blue line flashes at top and another section of lines appears on the graph), I continued to increase the speed untill the drill was going full speed (I think I increased the speed 4 times).
I also took a full screen shot this time instead of a little snip of the graph.

lukec53

After further testing it seems like its only getting a signal from the two-tooth wheel, and not the 24. When I disconnect the CAS' red and white wires, I get the same graph in the logger. When I disconnect the Green and white/black wires, I get nothing showing in the logger.

PS. My set-up with the megastim DOES work (does exactly the same thing as when hooked up to the car) if I turn the RPM pots all the way down and then spin the CAS

lukec53

I've been playing around with this thing for a few weeks now and I'm getting nowhere...
I know for sure now that my extra VR circuit is the only one giving me the signal, the built-in one on the board is giving me nothing.
The only log I'm getting is like the one I posted, and I now have a sync error log if it helps any.

If ANYONE has any suggestions, please post them, I'm getting really frustrated, getting nowhere alone, but still don't want to lose hope..

lukec53

Here's that log

lukec53

Hey guys I finally got access to an oscilloscope! How many people can say they tested their megasquirt in a university professor's private reasearch lab? :P

Anyways, I started following my signal from the CAS forward. It seemed to be going fine untill R48 I think. I'm unsure if it was just a bad contact on the lead or not though, because right after that we started getting some weird noise from my power supply and had to fix that first.
After fixing the power supply, I noticed that maybe I should be testing with the power ON (it was off before). But when I tried with it on, I would only get VERY small waves, even right on the CAS. The prof helping me said waves that small should be considered noise..

Could somebody help me on this? What is the PROPER way to test the VR circuit with an oscilloscope?
Am I supposed to have the megasquirt power on or off during testing?

And SHOULD there be DC voltage anywhere in this circuit other than on the + pin on U7? I notice a positive DC shift on all pins of U7

muythaibxr

The way I always test it is to hook the scope up to each component and look at the signal.

You have to look at the circuit schematic and decide what signal you should see at each point.

At certain points you should see something like a sine wave, then when the signal gets through the circuit, you should see a +5v square wave. I don't have the schematic in front of me, but your prof should be able to help you figure out based on the schematic (freely available on megamanual.com) where the signal should go and what it should look like at each point.

You should definitely have the MS on when doing this testing, the components require power.

Ken

lukec53

I'm testing with the oscilloscope right now... I tried testing the input and output on two separate channels, and am not getting an output whatsoever. My input looks like sharp positive and negative curves, appropriately 3v, as I would expect to see.
I started following my circuit down, and could get that same waveform through VrIn, R45,R46, R47. I got the signal on ONE side of R51, D24, and on the centre pin of Q22.

Anywhere after that I get nothing. Even after I set the scope down to its minimum voltage (2mV), if I spin the CAS fast you can see some type of distorted signal meaning that if there is anything, it is a voltage too small for the scope to read.

I tested my other VR circuit in the "Proto area" on the input and output, and I see a sharp spiked line coming in, and a square-ish wave coming out.

What should I see on the other side of R51? Should I be getting a signal or is it SUPPOSED to die when it gets to "VCC"?

muythaibxr

After the transistors, you should be getting a square wave I believe. I think this means you either installed the transistors wrong, or they were damaged when they were installed.

That sounds correct.

Ken

lukec53

Thanks man, I actually do vaguely remember bridging two of the leads together when I first put it on, which means I had to hold the soldering iron on it a lot longer than usual in order to un-bridge them. I probably wrecked it then.
I ordered a couple extras yesterday from a local shop and they should be here in the next couple days. I'll let you know if this fixes it!

lukec53

THANK YOU muythaibxr! That was indeed my problem. Got my new Q22, soldered it in, and got rpm right away!