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-   -   Crankcrankcrankcrank... '99 n/a MS3 - No Start (https://www.miataturbo.net/megasquirt-18/crankcrankcrankcrank-99-n-ms3-no-start-92636/)

nick470 03-27-2017 06:19 PM

Crankcrankcrankcrank... '99 n/a MS3 - No Start
 
2 Attachment(s)
Trying to get my car fired up on a Brain-built MS3. No RPM signal, it just cranks and cranks and nothing happens. I've screwed with a few things (injector size in the pre-loaded tune was set to 420cc or something like that), but still not getting anywhere. What glaringly obvious thing am I missing? The car is a '99, 84mm/8.6:1, stock fuel and spark. Crank sensor is where it needs to be, and this ECU has been back to Brain for some tweaks to correct stuff the PO messed with. I *think* the board and harness are good. I did add a knock module, following DIYAutotune's instructions.

MSQ and startup log are attached.

Use lube please.

stefanst 03-27-2017 07:22 PM

You ain't got no synch!
Next step is to take a composite log and post it here.
Set Spark Mode to "Log crank&cam", make sure to power-cycle the MS, then record a composite log under the "diagnostics and high speed loggers" tab.

nick470 03-27-2017 07:30 PM


Originally Posted by stefanst (Post 1401691)
You ain't got no synch!
Next step is to take a composite log and post it here.
Set Spark Mode to "Log crank&cam", make sure to power-cycle the MS, then record a composite log under the "diagnostics and high speed loggers" tab.

Here ya go!

Hang on... it's uploading weird

nick470 03-27-2017 07:40 PM

1 Attachment(s)
this should work

stefanst 03-27-2017 08:01 PM

Your MS doesn't see the crank trigger. Did you set up R56 as per Braineacks instructions?

nick470 03-27-2017 08:12 PM

1 Attachment(s)

Originally Posted by stefanst (Post 1401702)
Your MS doesn't see the crank trigger. Did you set up R56 as per Braineacks instructions?

The documentation I have for my MS doesn't mention R56. I bought it secondhand, and the instructions forwarded to me are from 2012... This is what I've got

stefanst 03-27-2017 08:26 PM

Try this (not 100% sure if this is correct, but give it a go): Turn R56 about 12 turns to the fully anticlockwise position (you may or may not feel a “click”) and then turn R56 back about 6 turns clockwise.
Then take another composite log and see if it shows your crank signal.

nick470 03-27-2017 09:05 PM

Silly question, how will I know when it's at the fully ccw position? Does the pot just stop moving once you've spun the adjustment screw past a certain point?

nick470 03-27-2017 09:24 PM

1 Attachment(s)
Adjusted r56.... spun the screw ccw 12+ turns, didn't hear/feel a click. Then went back cw 6 turns. Attached is resulting log, still no start

stefanst 03-27-2017 09:34 PM

There is no endstop on the pot. So you did that right.
Still no crank signal. I suggest you check the wiring. Again, I'm not 100% that my setup instructions for R56 are correct for a brain-built unit. But if they are you probably have a problem with wiring.

stefanst 03-27-2017 09:34 PM

If it's easy enough, you could swap the crank and the cam signal wires- that would tell us if the problem is in the MS or in the wiring.

slowcarfast 03-27-2017 11:44 PM


Originally Posted by nick470 (Post 1401719)
Adjusted r56.... spun the screw ccw 12+ turns, didn't hear/feel a click. Then went back cw 6 turns. Attached is resulting log, still no start

*Nevermind, you already said crank sensor is in the right place.

Braineack 03-28-2017 10:08 AM

I have more luck turning the pot more like 7.5-8 turns try another (2) CW turns on it. Make sure R52 is spun at least (12) CCW.

double check the sensor is definitely positioned correctly.

nick470 03-28-2017 11:09 AM


Originally Posted by Braineack (Post 1401795)
I have more luck turning the pot more like 7.5-8 turns try another (2) CW turns on it. Make sure R52 is spun at least (12) CCW.

double check the sensor is definitely positioned correctly.

Thanks for the reply. I'll give the pot another 2 turns this evening. Crank sensor is tightened up snug to 1mm of feeler gauge shims off the tooth.

nick470 03-28-2017 06:18 PM

2 Attachment(s)
No dice. Turned R56 two more turns CW and backed R52 off 12+ turns CCW. Most recent composite log and tune attached.

nick470 03-28-2017 06:36 PM

1 Attachment(s)
Ignore that last log, my dumbass left the O2 output unplugged.

stefanst 03-28-2017 08:25 PM

Still no crank signal indeed.
Can you switch cam and crank signal? That would give us a pointer where the problem is.

nick470 03-28-2017 09:40 PM


Originally Posted by stefanst (Post 1401971)
Still no crank signal indeed.
Can you switch cam and crank signal? That would give us a pointer where the problem is.


Yep... getting to it. Opened up the MS and looking through everything to see if anything stands out to me. It all appears as it should to my novice eyes, and I have continuity across the harness for both crank and cam. I'll crimp on some connectors to the cam and crank wires in a moment here so I can flip em.

stefanst 03-28-2017 10:22 PM

Just one thing that may have slipped through the cracks- what is your spark mode in TS set to currently?

nick470 03-28-2017 10:43 PM

1 Attachment(s)
As requested, cranking with cam and crank wires flipped


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