lost sync reason 38 (4g63)
 

hi how do you fix lost sync reason 38?
car is 1990 miata running a 1.8 with 1.6 harness and tps. no a/c
thank you

this is how its wired up

Please post a composite log of the problem too.

thank you for your reply
when i did a trigger log nothing came up

ok after many more hours of research i found out what the problem is.
apparently i need the 2nd opto circuit for the cam signal for people after me
Second Opto circuit in VR space on 3.0 PCB - Miata Turbo Forum - It's the Cat's Meow
how the hard part how the #### am i gonna build that

I've never needed that circuit. And I've probably built 20-25 MS2 units without that circuit and none had issues. Although Reverant WILL beg to differ.

yea i dont know, ive check everything else and it seems ok so only thing ive found is this.
did you follow this for your tach select etc..
Megasquirt 2 Assembly - Miata Turbo FAQ

I wrote that. :)

wow!
well ive followed every step from that guide, when i 1st had the ms2 r39 was jumped, ive now replaced with the resistor. ive checked over so many times and still no luck.
you reckon you can send me a picture of a finished board upper side so i can compare with mine??
thank you.

Can you post a screenshot of the capture of your composite log? I want to see if it's the CMP or CMK signal that's dropping.


From what I see your board looks built correctly.

jimstim out of battery and its 12am here so ill get back to you on thanks for your help!

you should be able to open the one you uploaded in TS and review it :) if you have it handy, or if anyone else can. I can't view it here.

okay I opened it in word. It appears the cam singal is not coming across properly.

so that would be the input on JS11 with the pull up to 5v. You have a 470ohm resistor on there?

my js11 has nothing on it

Sorry meant JS10

You absolutely need the second opto circuit for the 90-97 with the MS2.

so ive got iac1a to js10(ign) then a resistor to +5v.
the resistor is wraped in heat shrink so i cut both end out and unwrap it
and it is the 470ohm ffs
just to make sure is it
yellow violet brownish gold?

also Reverant have you got a picture of the circuit done on the daughter card??
if its not too much can you post it up
thank you.

I guess you're probably going to need to do the opto circuit.

I still think it's odd as I've never run into the issue, but others have. I myself ran without, and I have at least 3 other locals still running ms2 without it here, as well as a handful of others.

I believe the issue you're having is that the input isn't pulsing. The CAS is not dropping the input to JS10 back low to ground. So on your composite log, I'd expect too see a sold green line, a constantly pulsing blue line (up down up down up down), and a red line that pulses every few moments; all in a pattern.


the circuit is pretty easy:

https://www.miataturbo.net/attachmen...ine=1352818226

you'd build it in the proto area, not on the daughterboard.

thanks for your help braineack