ms2 cas pull in
 

I built the cam circuit based off the miataturbo wiki for my MS2, who else did and has anyone also have loss of sync?

Currently I bought the parts to build the circuit with the optoisolator in it, hopefully once built and installed I will get rid of my issues with sync loss.

(Posting from my phone.)

Never has sync loss issue with that circuit.

Me neither. No sync loss with that circuit. I did have a no sync, no start issue before but it was due to a bad battery .

I've always had sync loss on the 4G63 without the optoisolator on the cam input (on the MS2). The optoisolator fixed the problem every single time.

Only other thing I can think of is bad harness wiring. I'm gonna implement the circuit and see if my sync loss goes away.

Tried implementing the circuit, no responce back, hopefully I didn't kill it but will see.

For the ones running the 5v pull up only do you also have a cap mod on the ms2 board?

no. the cap is a MSI_hires thing

just the crank input through the opto circuit and the cam straight to JS10 with a 470ohm pullup to 5v.


built at least 20 that way, never a sync issue. Including two MS3x's I did in the last two weeks.

Built at least 10 that way, all had syncing issues (4-5 within a 30 minute drive).

I blame the lack of The Force.


This also includes my own personal MS2 and MS3x

this, every drive few minutes in the car will lose connection to the ecu~
I don't allways log code 38 sometimes its a drop out of all stuff on my logs, buts it noteicable and annoying. At higher power levels its getting annoying as now it started showing up as error 38.

brain can I see a pic of how your ms2 pcb v3 board mods are laid out for cas pull in and spark out?

That is racist.

CRAP I think I killed the ms2 chip, pissed. Testing to figure out.

Looks like I fried my 5 volt voltage regulator.

(Posting from my phone.)

You're doing it wrongg

my 5volt voltage regulator was bad, also my cap at F1 is bad as well, have to wait to replace it as well, just glad I may have a chance of getting back up and running.

F1 is not a cap, it is a polyfuse - a fuse that stops any more flow over 0.55A.

Yeah, I got a two of those poly fuses from diyautotune, installed a new one, seems same thing

There must be a short somewhere, maybe one of the diodes got killed, but they all check out on the power circuit.
I purchased the LM7805c and put it in place of the one sent with the kit by diyautotune. that worked to get 5v going, but still polyfuse is hot and doing its job by breaking the circuit.

I checked all the diodes on the power circuit, all check fine. Anyone have another idea of which part maybe causing a short? Maybe a transistor got fried internally and is stuck with pins connected?

Someone measure resistantce at U4 between 3 to 5, 3 to 6, 3 to 7 and let me know what numbers you get?
no power of course.

Back to what this thread is about, after getting my MS working it riding around last night I think I noticed same issue. I am gonna add the cap to the ms2 cpu, hopefully that will clear stuff up.

it wont -- dont cap on the ms2.

Besides, you have to do it after the 1K inline resistor before the CPU which is on the daughterboard itself.

Yes thats were it would go iirc.

http://www.dsmtuners.com/forums/tuni...t-2-setup.html
http://msextra.com/forums/viewtopic....r=asc&start=20

ask me how i know....

https://www.miataturbo.net/attachmen...ine=1317138037


doing this made it unusable on any of the newer 94-97 CASes -- couldn't go above 2500RPM


It was completely unnessecary on my 93 and it was removed and never done again.

what size cap, and what do you mean completely unnessecary on your 93?

hmmm
here is his mod
https://www.miataturbo.net/attachmen...ine=1317138965

may end up trying to reimplment the 2nd optoisolator again.

The .1uF cap on my board is on the cam in (after the 1K) and ground (pin 2).

Looks like he went to ground through that wire back to the mainboard?

It was unnessecary because it didn't do anything. I put it on because I knew no better, I was one of the first here that went to MSII, I brought that over form my MSI which I needed on the high-res code, just like everyone else.

I ultimately removed the cap after I built a MSII for a local on his 97 and we couldn't get it above 2500RPM due to that cap.

says he wired it to pin 2 of the cpu, gnd pin

that's exactly what I did. Dunno why it's going out to that wire. You can see the other end of the cap is going to the same spot mine is on (follow the via back to the resistor).

Yeah well I'm having drop out issues thats annoying me, so I will try this and see what happens.

Dude, I don't understand why you don't try the optoisolator circuit, which I can almost guarantee will fix the issue.

I used to get an occasional loss of sync with MS2, like once every 60-90 minutes of driving. It was annoying but not nearly as bad as some people have it. I was gonna install the optoiso but wound up implementing a far more expensive solution: upgrading to MS3. Works like a champ, never a single hiccup. :bigtu:

I have that loss of sync on my 94 cas with MS2 built as per wiki. I was wondering what was going on... happens about once every 1-2 hours.

If I were to run a trigger wheel setup using Trackspeed trigger wheel, would that fix it? (In addition to more accurate timing)

No it won't, because the problem is with the cam sensor, the crank sensor already has the optoisolator circuit.

see attached pic.

So far so good, I did the cap mod a month back and it didn't seem to fix it but after reopening the ms2 I found the wire broke. I reattached and did several back to back pulls, no break up so far. Feels good not to have it messing up.