kero

I am trying to switch over my MS-I Miata to a 36-1 setup.

I installed the OEM Protege wheel that everyone has been using. Since my oil pump does not have the hole for the stock NB Crankshaft Position Sensor, I made a bracket to hold it in place.

I wired the sensor up using the instructions found for FM's wheel that uses the same sensor:
http://www.flyinmiata.com/support/in...ng%20wheel.pdf

Setup Tunerstudio as 36-1
Using Configuring Megasquirt for a DIYAutotune.com trigger wheel
Which had me set
Trig A: 3
Trig A return: 8
Trig B: 21
Trig B return: 26

Went to start it, cranks but nothing happens, no fuel no spark.

Tunerstudio reads no rpm.

Checked my wiring for the sensor, turns out I had power and ground switched. Switched them around and tried it again. Still does not fire but now I saw PW but still no rpm. Did I fry the sensor?

Do I need to modify my MSI? (running standard miata mods)

I did try to run tooth logger and cranked it. Nothing showed up, then I had a few teeth randomly show up (still didn't fire) and then back to no teeth.

Matt Cramer

Can you check the sensor's output with a volt meter while turning the engine with a breaker bar with the key on? It should go from 0 to 12 volts and back again as the teeth pass under it.

Also, can you post a tooth log of an attempted start?

kero

It is alternating between 2.5v (no tooth) and 5v (tooth).

Megasquirt wont see any tooth in the log, so the log is literally empty.

Is this signal usable for MS?

kero

This is the circuit that I'm using
( disregard the original pull up, that is removed)

kero

ok so from doing some extra reading it should be switched to 0v whenever a tooth passes by.

Do I need to use a different size pullup resistor? (using 470ohm currently)

Matt Cramer

Can you check the current when there is a tooth in front of it? When using the opto circuit, you need at least 10 mA to trigger.

kero

I switched to a different sensor (2007 Dodge Caliber, $12 at Advance Auto Parts) made a mount and now the car runs. Either the 2 NB sensors I bought/tried are defective or I'm crazy. Anyway, looks I'll be running the Dodge sensor with a custom mount