Update 4/20/17:

UPDATE:
The crank sensor was loose enough to walk under vibration. I got stranded again and the sensor was too close too the trigger wheel. I increased the gap and it fired right up. Snuggled it down at about two card thicknesses and haven't had a problem since. Will update if it continues.


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Drove home yesterday, everything was peachy. Finished watching "You are wanted" on amazon prime, highly recommended. Woke up, hit snooze for an hour, then decided I should just go to work. Crank crank crank....

Things I've confirmed:
-Fuel Pump primes
-Fuel pressure exists
-Spark works in spark test mode
-Composite log does not see crank/cam triggers
-There is 12V to the crank/cam sensors
-Voltage is good on the battery
-Crank sensor distance is credit card length


I'm going to search concurrent to this post, but I put this out here for faster answers because a day of annual leave is at stake. Could both pickups have gone bad at the same time? I beg your forgiveness.

 

Main relay ?

 

My bad , you have fuel pump prime so it's not the relay .

 

im scratching my head trying to figure out why the MS wouldnt see both sensors all of a sudden...

 

Do you own a scope or one of those $10 Ebay Logic testers? If so, you can check the output from the signal detection circuit. The signal for the crank should be available at the Tsel jumper. (Not the TachSelect) If you don't have one of those, you could try a 1k resistor and an LED to see if you get signal out of the circuit. The Scope and/or the LED/resistor should also work on the input from the sensor directly.

 

https://www.miataturbo.net/megasquir...-signal-78225/

This thread sounds similar to my problem. Crank but nothing plots, and it doesn't catch. Sadly, it wasn't updated with a resolution. Digging through his later posts... @6strngs?

 

I don't have a scope :(

::searching now what Tsel jumper is::

 

Confirm both crank and cam still have ground. Maybe you got a loose ground on the back of the intake manifold.

Otherwise you need some way to scope the crank/cam signal. If they are there then you know its the megasquirt. But for them both to just suddenly stop working has to be some sort of blown hardware.

 

its two different circuits too: one on the mainboard and one on the expander.

he COULD use a DMM in diode mode and listen for pulses to ground...

 

If his DMM reacts that fast. Mine sure as hell doesn't.

Does the cam/crank pull to ground? Or output 5v?

 

Oh my god guys/gals.

I successfully checked continuity on both crank and cam sensors on the ecu plug and the respective sensor plug as well as ground. Plugged everything back in.

It.Starts.

FML i just called out of work for this. I appreciate everyone's brain power on this. I'm sorry.

 

Loose connector?

 

Missing 12V or ground to CAS, if using the CAS. If you are using the 99-95 crank/cam sensors, you have probably used the 12V/ground coming from the CAS for both sensors, in which case, test both sensors for 12V and ground.

 

The ECU connector is tight, I had to use my girly fingernails to pry it. I don't know if it was the crank and cam sensor plugs simultaneously loosening.

 

You are right, I shared 12V from CAS, and the voltage checked out on both sensor ends as did ground. I fail at the basics and it may have ended up being the ECU connector. I'll never know for sure.

 

Usually if you can get the ecu connector out with your fingernails its loose. I have to use a screw driver.

 

Is there a way to tighten things back up, or do ECU pins/connector ever need cleaning?

I love your new sig pic btw. I would have posted a log but it was uneventful. I was surprised that so many other ancillary things functioned with one ECU connector being loose. I'm going to go read up some wiring diagrams now. I'm glad I didn't have to open up the megasquirt because adding wires to the db37 is terrifying enough.

Again, you guys rock, I'd buy you beers.

 

They make connector cleaning spray. I've never used it.

You would be surprised how many things work with sketchy connections, but usually engine sensors are not one of those lol.

 

Since you are off of work and have resolved your issue that means we can meet up for a lunch/ bier?

 

Sure, I was going to try to get a head start at changing my fuel pump, but it's cold out, I'll wait to tomorrow for all that.