duffbuster243

iTrader: (1)

Even after upgrading to MS2 I am still getting a loss of sync or random dropouts, not as often as with MS1 but still enough to annoy me. While looking around I have found what seems to be the end all solution to the problem, which is making a second optoisolator circuit. I have found a diagram posted by Brain floating which I posted along with a picture of it on a board. Please verify that it in fact looks correct.

Braineack

iTrader: (62)

is the above yours?


do you have a composite log of your current sync loss?

duffbuster243

iTrader: (1)

The above is not mine, just one I found and scribbled out what I believe does not pertain to the circuit and changed pin 2 from spr1 to IAC1A. I don't have a current log with it happening as my old tuning laptop's motherboard fried. I can probably get one next time I have the car out but the way the weather has been lately that may be a week or two.

duffbuster243

iTrader: (1)

I did purchase 15ft of shielded wire which I am going to use to rewire both CAS signals directly to the Megasquirt box to see if it makes a difference.

Braineack

iTrader: (62)

I'd like to see a composite log of your inputs from the CAS.

Circuit above seems correct, Been a while, just follow the diagram, did you need it again?

Joe Perez

iTrader: (8)

A second opto is a second band-aid.

If you want a proven reliable input circuit, build this:

Braineack

iTrader: (62)

even better and still incredibly easy.

duffbuster243

iTrader: (1)

I'm not quite good with circuits, and that appears simple, almost looks like it would be easier to do on a separate wafer. Does anyone have a picture of this done?

Joe Perez

iTrader: (8)

You could easily build it in the proto area, assuming it's not already filled with a bunch of other stuff. But yeah, a separate board would be ideal. If I weren't so lazy, I'd design a little JB-style daughterboard and offer them for sale.

I don't have any pictures of the actual circuit built, apart from this one, which is worthless for your purposes:


(It's the circuit that the red/wht and blk/wht wires go into.)


In all seriousness, would you guys actually buy a little board containing this dual-input conditioning circuit?

emilio700

iTrader: (3)

It won't. (sorry)

Reverant

iTrader: (10)

And your evidence for this?

Joe Perez

iTrader: (8)

Dictum meum pactum.

Reverant

iTrader: (10)

Sorry, you need to try harder.

Joe Perez

iTrader: (8)

I tried really hard several years ago when I was doing the initial install on my '92. Wound up saying "**** it" and building a 36-1 crankwheel setup. (This was, admittedly, a rather disproportionate response to the situation.)

The 40106 solution has excellent filtering and hysteresis, and doesn't rely upon current-mode devices which offend my sensibilities.

duffbuster243

iTrader: (1)

I'm willing to try this. I added my inputs/outputs on. Is this correct?

Ben

iTrader: (33)

Do you have a composite log showing loss of sync?

Joe Perez

iTrader: (8)

That's correct. Depending on how you have your cam input wired now, you may need to flip the polarity setting (in software) for that input after you build this circuit. I can't remember what it's called on the MS2. Also, you'll need to re-calibrate the hardware latency. This circuit has a very long time-constant by design.

The value and stability of C120 and C125 are highly critical. Use low-tolerance parts here (eg: 5%, C0G).

duffbuster243

iTrader: (1)

I do not, How do I do a composite log in Tunerstudio?

Ben

iTrader: (33)

Under the diagnostics tab.
You're chasing your tail if you haven't taken a composite log first. It will show you (if) you have a sync problem, and if so, which sensor is not coming through.

I am generally amazed at when I see a report of a sync problem on a Miata. I personally have numerous Miata installs under my belt, as in I can't count/remember them all, and have never had a sync problem. As a company, Miata is one of our top selling applications, and I don't recall any sync problems with any of our prebuilt units if correctly installed.

Full_Tilt_Boogie

iTrader: (1)

What makes the CD40106 trigger superior to an opto-isolator?