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Baseline MSQ for '99-00, including Abe's Board

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Old 10-14-2009, 01:37 AM
  #141  
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Yea, according to your parts list, you have 10nf that was added onto the board, C1 and C2

https://www.miataturbo.net/forum/t36300-5/#post444051
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Old 10-14-2009, 02:36 AM
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There's so no WAY I kept that in there!

Well, all the more reason to pull it out. 10 nf would run the risk of swallowing signals (though, honestly, at higher RPMs. I worked it out once, and then tested it with a scope)....

1 nf is what you want to have what Mazda uses. ~1/2 that would work. You can put 2 220's in series to hit 110 which is close enough. But first, just try taking them out, and trust in the magic of the op-amp to give you all you need (though details which would only interest an EE, an op-amp as I have will ignore any state change shorter than a particular length, and the specific op-amp chosen was so chosen because it is particularly selective.)

And if not, start at 1nf and go down. 10 should work, but only barely.

If it's just the time to start, even so, a factor of 10 will help.
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Old 10-14-2009, 03:53 AM
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lame, so i bought the wrong capacitors. Set me back like 5 bucks. oh well.

Jameco is local here, and they got a bunch of capacitor sizes available. That small of a size of caps cant be found in frys unfortunately.

Does this mean all people's boards should be fixed since a 10pf cap was placed in there?


Abe, would a 470pf cap work as well?


Well, in any case, I will remove the caps and see how the circuit works without them. If I get some of those hick ups again, ill see into getting those caps ordered.

Last edited by Marc D; 10-14-2009 at 04:41 AM.
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Old 10-14-2009, 12:55 PM
  #144  
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Yeah, if people aren't having issues then I wouldn't worry about it - the two (caps and op-amps) are pretty complimentary and relatively independent.

1000 pf should work, it's actually what's designed in by Mazda. 470 would be really good, probably what I would use if I were to put some in. Just run without them for a while, like you said, let us know if you get a difference.
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Old 10-14-2009, 01:35 PM
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Originally Posted by AbeFM
Yeah, if people aren't having issues then I wouldn't worry about it - the two (caps and op-amps) are pretty complimentary and relatively independent.

1000 pf should work, it's actually what's designed in by Mazda. 470 would be really good, probably what I would use if I were to put some in. Just run without them for a while, like you said, let us know if you get a difference.
Got it.

thirdgen did say he had some "hick ups" too if you remember, Although he has issues with his alternator ATM.

I'm going to order some 470pf capacitors to try out.
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Old 10-14-2009, 01:42 PM
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I pulled my alternator this morning and I ordered a new one, will have it tomorrow. I will do a few logs and clean up my fuel table, and then I'll report back with issues if any.
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Old 10-14-2009, 01:49 PM
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If it's apart anyway, you might as well pull those caps.
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Old 10-14-2009, 02:07 PM
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They are 470pf caps. 50V rating, and they are temperature rated at NP0. Jason recommended using either X7R or NP0 rated temperature coefficients in the cam and crank input circuit thread IIRC.

I ordered about 12 of them, two of them will be for my use.

Last edited by Marc D; 10-14-2009 at 03:14 PM.
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Old 10-14-2009, 02:31 PM
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Heh. Big Money.

I work in a place where many of the products end up in satellites. I am used to seeing capacitors with a $300 price tag, and minimum buys on top of that. We were just roughing out a system with 3 $75,000 FPGAs. Good lord. Anyway, sorry, just on my mind. :-P

At minimum, this should help, the "pause" you need before starting will be roughly a factor of ten better - and hopefully less skipping now, too!
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Old 10-14-2009, 03:04 PM
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Wowzers.

Haha yea, this should definately help. Gonna be a busy weekend. Gotta take apart the megasquirt again. Hopefully for the last time. I will make sure its running fair and square before i get started on the bluetooth thing though. I've been building a BS harness for a friend though, thats been taking a huge amount of time.
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Old 10-14-2009, 03:09 PM
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BS?

The bluetooth thing is clever. Wish it were a lot cheaper. :-) I keep ALMOST soldering my serial adapter into my case, and then not doing it, and then regretting it. :-) I will soon, a USB plug is a nice thing to just have on there.
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Old 10-14-2009, 03:24 PM
  #152  
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very true.

BS = "boomslang" style patch harness.

Yea, the project turned out to be a little more expensive than I predicted. that "semiconductor store" raped me on shipping charges. 10 bucks for something that weighs a few ounces? I guess they used very expensive packing peanuts.

Anyway, it should be up and running soon. It's very awesome, it allows you to bypass the module completely for serial cable use by giving a simple command. Hell, I could even solder on the serial-USB converter as well! haha
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Old 10-14-2009, 04:39 PM
  #153  
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Ah, that IS very nice. Unreliable is ok if you're just going to switch back and forth.

Someday soon, my dashboard will likely have two USB ports, one for the MS, one for a pendrive filled with music. :-)
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Old 10-14-2009, 04:45 PM
  #154  
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Are you guys using "Falling Edge" for ignition capture? I don't think it should be that. The signal from the crank is active low, and my circuit inverts this. I remember one edge was unreliable, and I was pretty sure it was the trailing edge (makes sense, anyway).

Given all that, rising edge capture should be what you want. I remember getting that, skipping especially at low speeds, because the mazda sensor basically sucks at low speed.

It'd also explain a small timing difference if you're seeing one.
edit:
Huh. Looks like you're using falling edge too. And given the funky issues my friend was having when starting... I must have it backwards. Plus, my own MSQ uses falling. Of course, there was only issues on startup when using the wrong one.


What's got me is the sensor is open collector, and, you have a pullup to +5, a cap to ground (still mislabeled 10nf!), and it goes into the INVERTING input. So, high all the time, leading tooth edge will be pulling down. The op-amp inverts this, giving you a rising edge on the leading tooth.

Well, you'll have to retweak your timing (by the width of a tooth, 4 degrees, I think)...

Anyway, I guess I'll try it first on my car. :-) But I remember when it's wrong, it's bad-wrong, so I bet its right. The issue is all mazda's hokey sensor.

Last edited by AbeFM; 10-14-2009 at 05:20 PM.
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Old 10-14-2009, 05:27 PM
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Ok, that settles it. Just went and tried it both ways. It's definitely falling edge that you want.

If you look enough, you'll find threads where this information is shown, that the sensors suck on one edge. I thought it was the trailing edge, but it must be the leading.

At minimum, it restores my faith in my abilities to write an MSQ. :-) For a while I couldn't figure out the magic in yours Marc, now I know. You followed my write up. :-P

Sorry for the false alarm everyone.
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Old 10-14-2009, 09:50 PM
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You found out my secret! Damn!


Ha.

Well you had a good scare on me with that setting for a second, good thing you tested it out before I **** with something again
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Old 10-31-2009, 11:32 AM
  #157  
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Installed my MSII / Adapterboard this morning. Sensors seem to work fine, RPM runs correctly. Started first try no issues. Don't be alarmed if your RPM's don't work with your stim, mine did not even with the correct chip.

Waiting for battery to charge as car has been sitting, then will move on to tuning, currently so rich that it will not idle correctly.

I have 270CC high ohm injectors, betting it's just a pulse width adjustment.

Last edited by MWMIata; 10-31-2009 at 01:22 PM.
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Old 10-31-2009, 05:09 PM
  #158  
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Yeah, opening time can be a bare, then it's actual tuning. Again, check MAP, MAT, AIT before you start, make sure they are all sensible, then it's just tuning the injectors and laying down skidmarks. :-P Well, at least getting running.
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Old 11-07-2009, 10:00 AM
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Default Issues with my MSQ

I did get my car to start won't idle, smells rich. I assume problem with my MSQ. Car cough's on startup if I give it some gas I can get it to run above 1500rpm's AFR is rich at 10-11 on startup.



MSII / Abe's adapterboard. 1999 miata Stock coil setup, 270cc high ohm injectors. Innovate LM1

Thank You

MSQ
Attached Files
File Type: msq
megasquirt2.1.1b99miata.msq (51.7 KB, 92 views)

Last edited by MWMIata; 11-07-2009 at 04:28 PM.
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Old 11-08-2009, 01:02 PM
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Interesting. Your msq is nearly empty, with a short short section that just talks about MS-DOS5.0 and disc write errors. Your earlier MSQ's look ok, but come up as 2.1.1a instead of 2.1.1b - of course, there's not enough information in there to REALLY know what it is, the guys at MSx don't think a version of code needs a single unique and unambiguous identifier.
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