No crank signal

[KAT PWR]

Hello, I'm currently in the process of setting up MS3X (pcb V3.0) full sequential with LS truck coils, on 91 Nissan 240sx with a turbo KA24DE. The other day I was going through the startup checks, to find that I wasn't getting a cam or crank signal from the distributor. probed my distributor with a multimeter looking for a 5v and 0v alternating signal on cam and crank. Cam gave me a good readout while crank gave me a straight 0.01V. looking things over the I found that I messed up the distributor wiring mixing Gnd and crank signal. Retested after swapping the 2 pins, the crank signal still only getting a .01v output, with no voltage fluctuation when rotating the distributor. I checked the render non-interrupt data box in the composite logger and found that I'm only getting a cam signal. Opened up my ecu and verified that I followed the instructions on DIYauto https://www.diyautotune.com/support/tec ... gger-disc/ for my trigger wheel install.

Using the MS-III V3.0 or V3.57 ECU with MS3X for full sequential

The MS3 manual generally favors the VR input, so we’ll be using that.
Place the JP1 jumper in the 1-2 position for a V3.57. For a V3.0, jumper TachSelect to VRIN.
Place the J1 jumper in the 3-4 position for a V3.57. For a V3.0, jumper TSEL to VROUT.
Put a 1K resistor in the R57 slot on a V3.57. For a V3.0, run a 1K resistor from S12 to TachSelect. (Or you can use a 1K pull up in the wiring from a 12 volt source to pin 24 of the main board.)
The second trigger input also needs a pull-up. Install JP7.
TunerStudio settings (Sequential coil on plug and / or sequential fuel): All are under Ignition Settings -> Ignition Options / Wheel Decoder.

Spark mode: Toothed Wheel
Ignition input capture: Rising Edge
Spark output will depend on what output setup you’re using. QuadSparks use Going High / Inverted; so do OEM SR20DET ignition modules. Getting this setting wrong can damage the ignition module and/or coils. If the ignition module or coils get hot with the key on and the engine off, turn the key off immediately and select the opposite output setting.
Trigger wheel arrangement: Dual wheel with missing tooth
Trigger wheel teeth: 12
Missing Teeth: 1
Tooth #1 angle: 345 (This varies slightly between individual engines. Check with a timing light and adjust as needed.)
Wheel speed: Crank wheel
Second trigger active on: Poll Level

Afterward I verified that the distributor was outputting a valid crank signal by swapping the cam and crank pin at the distributor. I got a healthy crank signal through the cam input. Which narrows it down to either a build error or something got fried when I had my distributor wired wrong.

I'm currently waiting on a jimstim v1.5 and spare components coming in on Thursday. I ordered all of the components for the Vr circuit per page 199 of the MS3X hardware manual, although DIYauto does not sell D24. So I can bench test the ecu and diagnose the circuit. I have chipped ecus and built simple circuit boards in the past. But this would be my first time diagnosing a circuit on a pcb, yet alone this complex, and I would like some insight on how to test it.

[elutionsdesign]

It sounds to me like your pull up on the main board (crank signal) isn't pulling up. Check the added resistor to be sure it was installed correctly.

Put a 1K resistor in the R57 slot on a V3.57. For a V3.0, run a 1K resistor from S12 to TachSelect. (Or you can use a 1K pull up in the wiring from a 12 volt source to pin 24 of the main board.)

[KAT PWR]

You are correct. Tried the Jimstim with the stim pull up non jumpered no crank signal. But if I cut my pull up from s12 to tachselect and use the Jimstim pull up to 12v, I get a valid crank signal and tunerstudio now shows rpms. I tried removing the jumper and going back to s12 with a 1k 1/6watt resistor connected to tachselect, then I get no crank again. S12 shows 12v and it operates fine with the jimstim pull up to 12v. At this point I'm quite connfused.

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[elutionsdesign]

I'll offer this in the hope I don't confuse you more. I've done a bunch of these and I've always used the opto circuit on the V3.0 main board, there are two ways given in the old MS1 documentation, http://www.msextra.com/doc/ms1extra/MS_ ... l.htm#hall and I follow the 2nd one where it says low with no tooth in front of the sensor and high with tooth in front, low to high. Works every time.

I'm sure the VR way works, not saying it doesn't, its just that when I started doing this stuff it wasn't an option for the CAS.

[KAT PWR]

i got the VRin circuit to work last nite, by cutting my internal 1k pull up from s12 to tach select and using the 12v pullup jumper on the jimstim. i forgot to record but i do have a picture.

but if i remove the jimstim jumper and put the internal pull up back in place i get no crank signal.

if I use both pull ups the crank signal copies the cam signal.

[KAT PWR]

I'll offer this in the hope I don't confuse you more. I've done a bunch of these and I've always used the opto circuit on the V3.0 main board, there are two ways given in the old MS1 documentation, http://www.msextra.com/doc/ms1extra/MS_ ... l.htm#hall and I follow the 2nd one where it says low with no tooth in front of the sensor and high with tooth in front, low to high. Works every time.

I'm sure the VR way works, not saying it doesn't, its just that when I started doing this stuff it wasn't an option for the CAS.

thank you for your help elutionsdesign. i got my 240sx to start yesterday after doing 2 things.
1 Added a 12v 1k pull up in the engine harness.
2 Then realized I had the pinout on the dizzy correct from the start but I had the shielding connected at black (crank signal) thinking it was ground. moved it to white (vr crank ground) fixing my issuse.