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-   -   No RPM signal (https://www.miataturbo.net/megasquirt-18/no-rpm-signal-49303/)

Splitime 07-05-2010 08:33 PM

No RPM signal
 
So the car died out on track. Literally died, and tach dropped out. No restarts. I have spark, the initial one you see upon ignition startup (due to me never updating my ignition circuit).

I can see 0 rpm signal during startup within TunerStudio.

Just tried another CAS that should have been working fine, also nothing. It came off a car that short nose crank failed... just in case... should i test with one off a running car? Or can i test these off the car?

I am using OEM wiring harness with my own standalone adapter harness. I checked all the wires and nothing is loose. Opened top of MS and nothing looks or smells fried.

Any thoughts?

Marc D 07-05-2010 09:52 PM


Originally Posted by Splitime (Post 597609)
So the car died out on track. Literally died, and tach dropped out. No restarts. I have spark, the initial one you see upon ignition startup (due to me never updating my ignition circuit).

I can see 0 rpm signal during startup within TunerStudio.

Just tried another CAS that should have been working fine, also nothing. It came off a car that short nose crank failed... just in case... should i test with one off a running car? Or can i test these off the car?

I am using OEM wiring harness with my own standalone adapter harness. I checked all the wires and nothing is loose. Opened top of MS and nothing looks or smells fried.

Any thoughts?

could be that that CAS is also dead. But what are the odds?

Those optical CAS sensors are horrible.

Splitime 07-05-2010 10:10 PM


Originally Posted by Marc D (Post 597640)
could be that that CAS is also dead. But what are the odds?

Those optical CAS sensors are horrible.

Yah... but they at least work.

It is possible I guess... I'll see about luring a buddy over and seeing if we can use an absolutely working one to test.

Is there any simple way to test these off car?

Splitime 07-05-2010 10:48 PM

So it looks like I'll be borrowing a locals Jim Stim, allowing me rule the MS out.

Next will be a known 100% good CAS.

I'll update as I go. Anyone with ideas, please feel free to chime in though.

Reverant 07-06-2010 04:00 AM

Snapped timing belt?

Splitime 07-06-2010 07:26 AM


Originally Posted by Reverant (Post 597707)
Snapped timing belt?

Nah, belt is only a few thousand miles old... not to mention its completely visible and exposed ;)

neogenesis2004 07-06-2010 07:44 AM

My guess is still wiring harness or MS.


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