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New FMII hydra 2.5 user - some questions

Old 02-22-2018, 10:56 AM
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Default New FMII hydra 2.5 user - some questions

I recently bought a '98 miata NB with an FMII kit including a hydra 2.5 ECU which was installed in '11. It had the FM injectors, exhaust and GT2560 turbocharger. So far I am enjoying it immensely, but as you might have guessed there are a few minor issues .

When I got it the idle speed dipped quite far below setpoint, to the point it would almost stall every time idle control kicked in. Using information from this forum I managed to get rid of the dips, but now my idle speed is a bit high (~1500rpm). I've been tinkering with the PID settings but have not yet managed to get it to play nice.

What isc PID settings are you using?

Check Engine light
Also, my check engine light does not light up on key on. Should it? I'm a bit worried the check engine light does not work at all..

Basic ECU settings
The previous owner said he had tinkered with various settings in the ECU, and I am not convinced that the changes he made are for the better. If anyone had a template.s20 file as it came from Flying Miata back in the day I would really appreciate it if you could send me this file!
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Old 02-22-2018, 02:01 PM
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Not too many people here use Hydra ECUs, so you aren't likely to get a whole lot of help. Doesn't FM provide support for their kits even after change of ownership?
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Old 02-22-2018, 02:04 PM
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I believe FM will provide support to a second owner of a Hydra for a one-time fee. That's probably your best choice.

I had a 2.5 Hydra, and idle control was never very good even at its best. I don't remember whether or not it lit the CEL at key on.

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Old 02-22-2018, 03:14 PM
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Thanks for the replies guys. I already got the idea that the hydra is kind of a niche product, as little information is availible on the internet. For now it does the job, so I don't plan on replacing it anytime soon. As I view it as a project car and it's not my daily driver I can live with some imperfections. As long as it puts a smile on my face when I apply the throttle it's fine .

If I run into more serious issues going the FM support route is a nice option, thanks for the suggestion. I might send an email to FM support to ask about the fee.

Out of curiosity, what do people run these days? From my limited, mostly googled together knowledge I would suspect Megasquirt? (I briefly looked in to MS2 on custom boards while I was looking to buy a miata).
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Old 02-22-2018, 03:18 PM
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Hydra is trash. Most of us use megasquirt. MS3
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