ms3x 5800rpm sync loss
 

Hey guys. Just finished building and loading firmware to my MS3x. I have been looking but cannot seem to find the base maps for the ms3? I am probably looking right over the damn things, but could yall possibly tell me where to find them and then ridicule me for not knowing??

93 miata all stock

Probably best off grabbing one from the mspnppro.

MegaSquirtPNP by DIYAutoTune.com

thanks aidandj, i was able to get the car started on that map. It currently acts like it has the 2 step active at 2500rpm, so i need to go through and check over things. hopefully have it sorted out tomorrow.

I believe that map has coolant rev limiter turned on by default maybe?

That was one of the things I checked but it was set to normal and not coolant based. I will check more things today.

fixed the limiter. i had left the 1k ohm resistor out that was supposed to go between 5v and tachselect. put that in and it seems to rev fine now.

I started screwing with idle. idle test works but it doesnt seem to accept it in closed loop. not sure whats up there.

i easily got the AC functioning however as above, it doesnt bump the idle like it should. more dicking around to do but very happy so far. Build start to running took about 8 hours total.

so i finally got a chance to drive and tune the car. Spent last week for 4th of july vacation and work travel to Trinidad.

Seems to drive great under normal conditions and idles ok. However it now cuts out at around 5800rpm or so and i can see the rpm sync flashing to red when it happens. I didnt a composite log but my fucking computer died in the middle of it. i will try to take another on my way to work tomorrow. I imagine its something in the cam sensor reading or something.

I will update with a composite log and msq tomorrow. if anyone has a thought on it, let me know.

RPM flashing red is a gauge setting. Not a tune.

rpm sync is going red

Ah. Yeah thats it loosing sync.

Get a composite log of it happening.

thats the plan tomorrow.

is the knock module required for the ms3x or is there somewhere it can easily be wired in?

Module is required.

https://www.diyautotune.com/product/...ck-module-kit/

uploaded some attachments. let me know what the thoughts are guys!

https://cimg1.ibsrv.net/gimg/www.mia...c16acb4215.png

See the gaps in the green lines? Your cam signal is cutting out.

No idea why. Bad connection, incorrectly adjusted pots. Noise. Etc.

for the dash pots i adjusted them per Franks writeup. I also added the 1k resistor the way frank does.

"– pullup for the VR circuit: Install a 1k resistor in the left hole of R13 (= 5V). Connect the other end to the right side of R45 just below it (= VRIN)"

"Fine adjustment of the VR circuits:
– For the main board, measure the voltage on the upper leg of R54 while turning R56.
– For the MS3X board, measure the voltage on the lower leg of R17 (close to U7) while turning R11.
In both cases, you want to see about 2.5 to 3 volts at that point, which puts you right in the middle of the actual output range of the sensors."

i am honestly not surprised if i have excessive noise. This is just at the initial install stage. i have the 10ft harness uncut running to a diybob i had laying around. The plan is that i use this temporarily while i am prepping my vvt swap. then once that goes in i will build a custom engine harness for the VVT engine that is completely made up of the MS wiring.

I'm still surprised its just cutting out like that. Do you have access to an oscilloscope?

Happen to have a second CAS that you can try?

i do have a second cas.

I should note that this car was running perfectly on a diypnp before i changed to the ms3x.

i have the shielded white wire from the ms3 db37(pin 24) going to 4e on the bob

unshielded green wire from ms3x db37(pin 32) to 4g

a question of curiosity. Does the black wire in the shielded loom need to be used? the bare wire is going to ground as it should.

I've been curious how DIY grounds their shield. You can probe around to see if the shield has continuity to the DB37 back shell or to any grounds. The shield must only be grounded on one side, so if DIY already grounded it at the ECU connector, than it should be ungrounded at the sensor side. Having both sides grounded would cause a current loop and can magnify noise.

interesting, i did not know that. i think i can go in and remove it from the MS side since i already have it grounded to the chassis.

i went ahead and disconnected one end of the shield wire. no change.

still having some difficulty with this and idle control.

the 1K resistor is a pull-up required to get the signal to show up at all.

when i do the pots, i dont measure voltage. Reset your R11 and turn in 3.5 turns back CW or in the least, turn yours another half turn CW.

ok, so i gave that a try.

i started turning the pot CCW until it stopped or clicked. It never did after at least 10 revolutions.

So i decided to hook up the jimstim and check the voltage at the lower leg of R17. It was at 1.57 now and i KNOW it was at 2.75 before. It will also not go up any higher unless i mess with the Hysteresis adjustment.

R11 busted?
JimStim not applying voltage to that circuit correctly? when i adjusted originally, i was using a spare battery and inline fuse wired to the ms3 db37.
im an idiot?

put it back in the car and retested the voltage at the bottom of R17, still only 1.5v

Ok, so its working right now. revving like it should. Here is what i did.

After the previous testing, i decided i would turn the hysteresis full CCW until it reached the max voltage reading i could get. 2.3 or so. I was going to try that because of the Brain quote below.

"im with everyone else on the adjusting pots now.

I dont even check voltages:
spin R52 & R56 CCW at least 12 times. Spin R56 CW 8.5 turns.
on the adpater board, spin the two back at least 6 times. Spin R11 CW 3.5 turns."

I put my voltmeter on it after turning it CCW and it was now reading 4.5v. WTF?? Ok, no clue what was going on before, possible multimeter being shitty. so i keep the hysteresis full CCW and adjust R11 to 2.95v(2.75v originally). Now the car is back to the super high revving stock 1.6 it should be.

thanks for all the support you bunch of flaming hairdressers.

Now on to make the idle right so i can run my AC!