MS3X-1.6 Sync loss @ 4K, high idle
 

Hello guys, I've been having some trouble with the MS. It has a high idle, starts around 1500 and works it's way up to ~2200 as the car warms up (16-17 AFR), which I have no idea why. And recently, on startup, it will start then a few seconds later die down unless I turn autotune on, which then it will idle. Also, the idle with jump up and down if I don't have overrun fuel cut off.

Lastly, it is experiencing sync loss at ~4K rpm, I'm pretty sure my pots are set up right. You can see my build thread here https://www.miataturbo.net/megasquir...y-build-62983/

Thanks for your time. I have attached my current tune and a couple datalogs. Please let me know if you need anything else that I can help with. I will not be able to work on the car until this weekend so I am trying to set up a game plan for when I go home for the weekend.

Is your idle control on the MS3X?

you're not using the correct output; you have "FIDLE" selected, not "Idle".

Fidle is the the output on the Mainboard... I dont suspect you built the pwm idle control circuit on the mainboard when the same is built intpo the expander card.

Switch that.

Otherwise the settings look okay...but the PID probably needs a little help.

Never autotune idle. I say that, but you can't anyways--it's filtered out when CL idle is active--PLUS you're using the VE idle table in which the autotune won't tune. If you need to fix your AFRs at idle, tune your Idle VE Table by hand.




For the sync loss issue: Composite log the event, find out what sensor is dropping out, then readjust the pot a bit (going more clockwise) until it doesn't drop out.

Thank you sir! I switched it from FIDLE to Idle, also I'm not sure what PID is. As far as the sync loss, I turn R56 more clockwise, correct? and leave the other one be.
Referring to this

So I went home today, switched the fidle to idle, and it literally took a half our to get the car to start. It would crank and crank and crank and shutter and puff. It started a few times but then died after a few seconds. But eventually it did start and idle normally, still high at 2k and I have not the first clue on how to adjust it down other than the screw on the TB.

I did a composite log of the sync loss but I have no idea what i'm looking at so I'll attach it for anyone to look at. I'll also attach my crank data log to see if there is anything funky.

Welp, I figured out a couple problems. The high Idle was due to it constantly pulling air through the IACV. Which I block both ends and the idle dropped down to normal. Thumbsup.

I also figured out why it was having such trouble in cold starts. My temp gauge in tunerstudio is stuck at like 180 iirc. The dash gauge is working. This makes me believe when I did my headgasket, the plug didn't seat right. Though, i can't get my hand behind to the plug to check it. Is there an easier way?

Now on the sync loss, this is probably completely wrong, but, can I literally turn the pot while the car is on and revving until it quit losing sync? Or what is the better way to do it?

Fixed the temperature problem. But I still need help with the sync loss. It is code 38 (4g63) and I found this thread https://www.miataturbo.net/megasquir...38-4g63-69396/
so do I need the opto circuit?

vr crank and expander cam right?

most likely pot adjustment issue.

I'm not sure how to tell to be honest. I attached a screenshot of the log. Let me know if I need to upload anything else.

Can you tell anything? I would loooove to get this fixed. And my cold idle.

Did you set the pots with a multimeter?

Yes sir

I would verify your grounds. This sounds similar to a problem I had where I hadn't paid attention to the grounds on my ms3x. Car ran fine but would lose sync at higher rpm.

composite log the events and see what signal is dropping out.

I have two separate ground wires going out to the fuel rail. What did you have to do?

That might not be the problem, but it's certainly a problem. The fuel rail isn't exactly a great ground. In fact, how exactly did you attach a ring terminal to the rail?
Anyway, you want to go to the head or block. Possibly the intake manifold. The key is very solid contact and clean surfaces.

Further, the MS3 + MS3X harness contains 10 ground wires. Not all are necessary, but why connect only 2 of 10?

Fix your grounds. ;)

I mean inside the case. You may have a loose ground or you are missing one on the ms3x.

With a ground problem you wil have errors build up so it will work at low rpm.

Whaaa I coulda swore I read somewhere that that is the place to ground it! :vash: My wideband is grounded there as well. On which part of the head/block exactly do you recommend grounding then? I grounded the wires already in the stock miata harness, and threw two extra ones out there, if that's what you mean. I can't remember how many are in the stock harness right now. If this is the actual problem, I will be so happy. :rofl:

do you have any grounds coming out of the expander board itself?

Yes. This be my harness for the expander. Only pic I could find
https://www.miataturbo.net/attachmen...ine=1358220508

that's the mainboard harness. what about the expander?

Whoop wrong pic. Fixed

okay and you said you ran them back to the fuel rail? or do they all just go back to the oem wiring harness?

All but two run through the oem harness. I have the two extra going out to the fuel rail by them selves.

You can kind've see them coming out of the single middle connector
https://www.miataturbo.net/attachmen...ine=1358311344

That should be sufficient, I dont even run extra grounds more than to the OEM ones myself.

Can you get a datalog and composite log of the loss of sync? that would really help to figure out the cause.

we can see if it's the cam signal, crank signal, or anything else...



edit: Oh I see you have already, I'll have to look when home.

The composite log in post #4 doesn't show any sync problems.

If it is intermittent, then it is most likely a loose ground or poor solder. I have seen a loose wire in the harness cause this.

probably because I uploaded the wrong log haha. Let's try this one.

There are no sync problems in this log.

Interesting. It shows a sync spike in megalog viewer HD for me. I'll try and make another log tomorrow if I get the chance.

Here is where I grounded it
https://www.miataturbo.net/attachmen...ine=1358610646

yeah there's no sync loss on that composite loss, only at the very last data point when the log was stopped, but that's only because it didn't read the signals further.

Next time it happens and you are logging hit <spacebar>, because that will put a mark in the log so we know specifically where to look.

I wish I read that before I did my logs like an hour ago :(

But here are some logs for you fine gents :party: hope these are better

I also have a few new questions.
1. What do you all use for idle control? And, could you screenshot your settings? I am currently using PWM closed-loop, and it would idle way high because it was constantly pulling air through the IACV, so I capped both end and it idles normal, except really low during warm up. Low enough that it will die if I try to drive before it warms up some.

2. With my idle VE on, it idles around 10AFR, and with it off, it wants to idle over 18AFR. I'd like to know you all's settings with this as well. Is it just as simple as taking away fuel from the idle VE map?

3. More settings I would be ecstatic for you all to help me with: Acceleration enrichment. Also, it goes extremely lean when trying to cruise with little gas or just giving it little gas in general. It also bucks when I give it a little amount of gas. I will also attach a log of this.

I would love to supply any settings of mine that would help. I appreciate all of the help :bigtu: :brain: I pulled my ECU and brought it to school with me to check over the innards and fix my LEDs, which I somehow put in backwards :facepalm:

Has anyone had a chance to look at these? I'm about to open up the squirt this weekend and look around

Took my MS apart today and hooked it up to the stim. Having weird problems with the tach input. Turning R56 until i get something and the tach signal go absolutely nuts. Data log says constant sync loss reason 38 (4g63). I also can't get any voltage above .17v on R54, turning R56. I am measuring voltage across the resistor right? Pos. probe on top leg and neg. probe on other leg of resistor?

Ignition settings:
Attachment 185634

maybe the pot resistor is bad?

you should be watching the composite logger while doing this too. to see what signal is kicking out.

I'm looking at the composite logger but again, idk what the heck I'm looking for. Just a bunch of lines going crazy. I don't have the stim for the expander card, could that be a problem possibility since the expander controls the cam input and such?

you just need to send the second trigger into pin 32 of the db37 of ms3x.

then when you sync and turn the rpms up, you can see if the top green line drops off or the bottom blue line, then you know what resistor is causing the issue.

I hope you are saying I can direct that in tuner studio and don't mean I have to mess with the harness :(

when you plug in the jimsitm to the MS. run a wire from the second trigger position to pin 32 of the ms3x.

it's pretty simple, want me to take a pic and show you?

OHH OK! Haha sure a picture would certainly help, if you wouldn't mind. I'm not exactly sure where the 'second trigger position' is that you are referring to.

here, i have my 2nd trigger jumper going to iac1a for all my non-expansion installs. so i use a jumper from iac1a to pin32 (cam in) of the expander to bring the cam signal in when using the stim.

https://www.miataturbo.net/attachmen...ine=1359918223

Should I have all of those jumpers installed? Cause I don't have a single one.

you just need the one.

those were useful back in to day for ms1 and ms2 installs where I could test outputs, I've just never removed them; I suppose I should.

Since everything is running off the ms3x card they are useless, and I need this: JimStimX Expansion Board - Assembled DIYAutoTune.com

Oh ok then hah. I haven't had a chance to test it yet due to school. But I ordered another pot from diy. Hopefully I can get around to messing with it tomorrow and have it going by weekend.

Added the jumper for the 3x cam in, but it's still going crazy. About to replace R56 in a couple minutes.

New pot R56 installed and it's still doing the same. Full counter clockwise, I'm geting .04v across the resistor. and 6-7 turns, I'm getting .09v What is going on here? Am I'm measuring the right place?
https://www.miataturbo.net/attachmen...ine=1360302139

I'm assuming you'd want the black lead on a ground and the red lead on the spot where you have the black above.

Yep, that's what I needed to hear. Got that set to about 2.8V and the max I can get out of R11 is 2.25V at R17 on the expander

Didn't have a lot of time today, but it seemed to have fixed the sync loss issue. Which I'm super pumped about. I still cant get the idle sorted out without it hunting, and it still has fluttery RPM deceleration.

are you on the latest firmware? if not what are you on? my idle is flawless.

1.1 Beta 21. It's probably because my idle settings aren't right. Do you use PWM closed-loop?

My IACV is also capped because it's constantly open

aaaand it looks like I'm not on the latest firmware. 1.2.0a is the latest correct?

yes closed loop and ve idle table and all the jazz.

Flashed the firmware this morning, fixed the WUE, and now the thing is running amazing! I been driving and tuning all day and I'm so excited that it is running so well now. It is getting poopy gas mileage though

Is the middle red LED supposed to stay on? Mine is on sometimes, sometimes never lights up, and sometimes flashes

Middle LED (assuming you've not re-purposed it for something else), is a WUE indicator.

I.e. when it's on you're in WUE

Ok that would make sense. And I'm assuming the right one is accel enrichment. Tried to do a couple mid range pulls and it feels kinda sluggish after 3k

Well now my tunerstudio hangs up on start up. It checks for updates, then says loading fonts or something and then it just hangs up. Tried reinstalling and updating java.