MS3X VVT - no crank and cam signal issue
 

Hi there,

Making progress with our MS3X VVT setup - have all basic sensors working as well as coils and injectors, but facing problem now with seeing no crank and cam sensor signals at all. Searched forums last night but still unclear as to what the correct MS3 hardware setup is for the Miata NB8B (2005 VVT engine) crank and cam sensors ... VR, Hall, or something else. Mazda is running a 12V supply to the crank and cam sensors which suggests that they are the hall-type, but the DIYAutoTune instructions for Miata suggest to use a VR input and that's how our MS3X hardware is configured now (jumpers set and pull ups installed).

The sensors are currently wired with a 12V supply, ground and the signal wires going to the MS3 (mainboard crank input / MS3X cam input).

The crank sensor is configured in TS as Miata 99-05, but we are not seeing any kind of signal in the composite logger.

Any guidance would be highly appreciated.

Thanks much in advance.

did you build it yourself?

Post pictures of your board.

They use hall sensors, but the VR input is like a universal input and can take in hall signals.

What documentation did you use to build it (if you built it yourself)? I used Westfields guide for the crank input with success: 99 ? 05 MS3 | Frank's Westfield MX5 99 ? 05 MS3 |

Go to Part 5, Step 2 in the Westfield guide and make sure your voltages check out.

adjust pots

Composite log and pot adjustment

Thanks for all replies.

Purchased the MS3X second hand from a friend who crashed his car (not a Miata). The crank input was originally configured for a hall sensor - we changed it to VR as this seemed what everyone is using for a Miata (higher noise suppression).
Used the DIYAutoTune v3.0 hardware manual as well as Frank's guide for the input modifications. The pots are all turned counter-clockwise as far as possible. Verified that the crank and cam sensors are getting 12V via fuel pump relay.
Sensors are grounded at our main ground location for everything MS3 at the back of the engine (intake side).

Hope to be able to pull a composite log and take the ecu apart for some pictures of the boards later this evening when home from work.

What's the correct setup for these sensors in TS?

Thanks much for all the help in advance :-)

MS3X board pictures
 

Attached are some pictures of my MS3X boards. Also tried to pull a crank log file from the composite logger, but all log files I recorded are empty (zero bytes), so there seems to be no data at all coming from the ecu, which is weird (they also don't upload as attachment here for some reason).

I will try to set the pots and check for 2.5V at the right places tomorrow.

Thanks much for your assistance in advance.

fwiw, you need a pullup on the adapter board too if you want alternator control to work.

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.

Thanks, Braineack. I will adjust the pots tonite and see if that fixes the problem.

Any recommendation on what the best setting for Ignition Options in TS is? "Miata 99-05" or is it better to chose "Toothed Wheel" and configure it for the 4-1 Mazda trigger wheel?

Cheers

Thanks also for the pointer regarding at the need for a pull up for alternator control. We are running a 94-97 alternator so are not going to use the alternator control feature in the MS3X.

99-05 obviously.

Some progress
 

Progress!!! Thanks for suggesting to adjust the input pots. We are getting signals now. The cam signal looks like it should be, but we are getting only a single bar from crank at the very end of the crank cycle. Please see attached composite logs.

Tried various different settings in TS (Ignition Options), but no change. Also adjusted the sensor / tooth wheel gap, but no difference either. Also played around with the R56 setting, again same result.

Any ideas, why the crank signals are not coming in as they should?

Thanks much in advance.
C.

Composite logger screen shot
 

Forgot to include the screen shot from the composite logger ...

Anyone willing to share a good base map for the VVT engine to get us started and the engine running?

Stock?

Sharing maps is like sharing condoms. Too many configurations: ribbed for her pleasure, fruity, studded, extra thin. Not everyone uses a magnum.

did you add a pull-up to the VR input circuit?

Yes, pull-up is installed with a 1k Ohm resistor - please see attached picture.

Could it be a defective crank sensor (how do you test it?) or a wrong setting in TS?

Thx.

What's the gap to the crank sensor? I spaced mine with a Safeway club card. CVS might work too.

I used my VISA Black Card

Adjusted the gap visually as best as possible yesterday, but will adjust it again today using the suggested plastic card and report back. Regarding the pull-up ... I used a 1k resistor - some people say the resistor should be 470k. Does this make a big difference in your experience?

Is there a good way to test the crank sensor? It's the one that came with our junk yard engine, so we have no way of knowing if it actually works.

Thanks.