mxteryman

I've been tinkering with my NB2 MS3 tune, it starts the way I want it to after a lot of messing with it. What it still does from time to time (and it's hard to get it to do it) is dies if I blip the throttle to 2-3k rpm and have lights on, or turn the steering wheel. RPMs seem to drop occasionally (to 5-600 - idle currently set at 1000) when I'm driving and coming up to a turn, clutch in, turn, and it seems close to dying.

Cameron took care of 95% of this by adding more fuel to the lower end of the map, I'm trying to do the cleanup work myself and would appreciate any input the Megasquirt Gods of Miata Turbo have!

Attaching the tune, log

LeoNA

Try raising your initial values. It seems odd that your idle valve min duty is 25.1. Seems a bit high. Could add a bit more air with the bypass screw and reset your idle duties. I set my non-iac controlled idle at 200rpm below my controlled idle. Also 20 deg of advance at idle is bit high, about 2x, 10-12 is plenty.

mxteryman

Appreciate the input.

I messed with the initial values yesterday and raised them, that does seem to work but the idle settles in first around 1500rpm and then comes down but that takes a bit. The car has very few miles on it (21k - original everything except transmission) and I know the previous owner, the IAC valve set screw is exactly how the car was put together, so I'm not inclined to fiddle with it yet. BUT I was setting the minimum duty at 25.1 as a 'backstop' thinking it would prevent stalling by keeping the IAC open. I have a handy dandy table I that i'm using to track my IAC valve percentages - though I only went down to 900RPM which is 24. I'll go and test it out

The car is turbo'd with larger injectors and upgraded fuel pump. Not sure if any of that matters for idle.

As far as the timing recommendation - timing in the closed loop table is way higher than that, 40 at 75% load and 10 at 18.5%.
I was thinking that the ignition table for Spark Advance would not apply since the presumably the car is in closed loop idle by that point.
Thoughts on this?

Going out to adjust a few things related to the initial values.

Thanks!

mxteryman

Well, I update the initial values to a smidge lower and reduced the dashpot adder to .8.

I ALSO lowered the values for timing advance to 10 to 15 in the timing in the closed loop table and in the 'regular' one.

It is spot on. Take your cat, sir,

LeoNA

There is nothing wrong with running the duty higher (30-40) for a normal idle and having the min at 25. It is just not common from what I have seen. I adjust my non-iac controlled idle to 200rpm below the controlled idle speed. Most likely your idle without the iac would be very low. Good luck

mxteryman

More tinkering and to me it seems like CL idle doesn't engage that quickly, not sure that's normal?

mxteryman

Is it equivalent to setting the IAC to a very low value, like 10? Thinking that setting below the minimum IAC (on the test mode) the idle is quite low, 700 or under. Maybe it's not the same thing?

LeoNA

In test mode you can go very low to check what the idle speed is with no addition air from the IAC. You can also set the target idle to 0. Either way you want the base idle to be lower then the controlled idle target with the IAC, but not so low that the engine will stall. If your idle is 900rpm then 700rpm without the IAC is good. My idle is set at 1krpm which is bit higher then normal because I'm running stiffer urethane motor mounts and my based idle is 700rpn and seems to work good.

Jamikins

iTrader: (1)

If you are running EGO, add some delay to the Ego Delay Table in the problem areas. My EGO was reacting to the blip (rich b/c of acceleration enrichment), pulling fuel on decel and leaning out the mixture as the IAC was opening to catch the dip, which was stalling the engine in certain circumstances (hope this makes sense).

LeoNA

Then you lose some of the benefits of having EGO correction react quickly on hot starts. Fuel cut is much more reactive then EGO anyway.

mxteryman

Hmmm - this EGO/Fuel Cut is a bit of a mystery to me. Anything you might suggest I read?

LeoNA

Ego correction and over-run fuel cut are two entirely different adjustment's. Fuel cut is for when the throttle is rapidly closed it will cut the fuel when the manifold pressure is low to prevent an over rich condition

rwyatt365

(Just to complete the thought)...and EGO is "real time" adjustment of the fueling to achieve targets that you've set in a MAP vs RPM vs AFR table.