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-   -   Open loop or closed loop but not both, a Valve Mode Mystery.... (https://www.miataturbo.net/megasquirt-18/open-loop-closed-loop-but-not-both-valve-mode-mystery-103545/)

Matthew Roberts 08-05-2020 08:14 PM

Open loop or closed loop but not both, a Valve Mode Mystery....
 
3 Attachment(s)
Okay, this is weird, and I'm sure its because I'm an idiot.
Car: 1990 Miata, 1.6L, MSDIY2, w vTPS, AEM UEGO, all works.
I can set up open-loop to work fine, as long as Valve Mode is 'inverted' idles around 900rpm, starts fine, runs fine, but when closed loop tries to activate, the IACV goes full open and the revs jump to 1700 and then the closed loop light goes out. (presumably because VPSdot is too high w/ the revs? but increasing it doesn't seem to change the behavior)
If I set Valve Mode to 'Normal' then open loop idle is really high (~2000) and I can't do anything to get it down (including cutting spark to 8* and fuel way back) but when closed loop kicks in, it takes right over and runs just fine (okay, a little high--1000rpm instead of the 850 target, but I can live with that)

I've attached my tune and two logs I took this afternoon. One with Valve Mode in each position.

Any thoughts?

ace-dragoon 08-12-2020 12:08 AM

engine size at 1606 and injectors at 275?

4strings 08-12-2020 09:42 AM

Have you tried out Idle Valve Output Test Mode? If bigger Duty% = higher RPM you'll know you have the Normal vs Inverted right.

Matthew Roberts 08-25-2020 09:56 AM

Okay...I'm an idiot. I figured that it would be something simple, and it was. I ended up hiring a remote tuner (Charlie) from the company that built my MS2 (Ohio ECU Solutions) and he pretty quickly found the problem: my Idle Valve Closed Duty and Idle Valve Open Duty values were reversed. I'm an idiot. Don't be like me.


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