mxteryman

I've got a Megasquirt 3 on my 2005 NB turbo. The car is a little 'weird', and when I get this sorted I'll divulge more details on why in another thread. The tuner warned me it wasn't ready and is busy with their own project(s) - trying to not bother them.

For now, relevant information is:
2005 NB - it used to be an Automatic. Now has a 5MT. Like I said, the car is 'weird'

When it starts, cold or not, it'll idle 'ok'. Until I blip the throttle, RPMs climb then fall and it stalls. It also stalls when RPMs fall while driving it.

What other info can I provide?

curly

iTrader: (25)

You're idling very briefly at 900 rpm before you blip it, at 38.8% idle duty cycle. But your initial value for that coolant/rpm range is 26.6, which it immediately goes to when you let off the throttle, and is way too low. I'd start by taking your entire initial value table and adding 10%. Your idle timing correction isn't doing much either, and has some strict activation requirements. Try increasing it's timing range to 10/-10, and just use PID idle activation for it.


Edit: your tune may be fine, and if you fixed any vacuum leaks recently, you may just need more throttle bypass. You may think about doing that first instead of adjusting the initial value table.

mxteryman

First of all, thank you for the assistance.

I was 'cheating' before by setting the idle valve settings to an initial value of 32%ish. I see where to adjust that, I think, in 'closed loop initial values', and just +10% across the board?

I see where to adjust Idle timing correction. 10/-10, do I need to worry about the RPM range and how smooth that graph is or do I just 'go for it' and change it to 10/-10 on the timing input? Follwo up, how do I use "PID idle activation" for it?

curly

iTrader: (25)

Yeah, start with 10% across the board. I'd rather have an idle settle high and be drawn down then the opposite, which can result in stalling.

under "idle advance settings", where it says "use normal activation", switch that to "use PID idle activation", then it'll turn on with your CL idle.

I use +10 at -100 rpm from target, and -10 at +100 rpm from target, seems to work well. I don't change them for the other 5 cells.

So sorta like this:

deg: 10 10 10 0 -10 -10 -10 -10
rpm d: -300 -200 -100 0 100 200 300 400

Hopefully that makes sense to you.

mxteryman

deg: 10 10 10 0 -10 -10 -10 -10
rpm d: -300 -200 -100 0 100 200 300 400

^^That's in the idle RPM timing correction curve, I think, right?

Thanks again!

curly

iTrader: (25)

Yeah. So at target it runs off your ignition tables, and adds timing to increase RPM, decreases to reduce it, CL reacts too slow otherwise.

Zero this out, and once idling, tune your ignition table for whatever timing creates the highest vacuum, then enter these settings and enjoy a rock steady idle.

mxteryman

Wanted to post back up and say THANK YOU

@vteckiller2000 did my work (build thread coming soon ). and he warned me it wasn't done. But because I'm a child I had to have it immediately. He even walked me through what you did - between the two of you I got my head around the fact that when I set my idle valve minimum duty to 31-ish it wouldn't die and that Mr. VtecKiller2000 told me that was a 'band-aid'...DUH! For the table you (and he) pointed me to it just overrides that so it never gets to the table.

Now I can get the idle valve all dialed in and understand what it's doing.

curly

iTrader: (25)

You don want your car to be able to idle with your IAC at 0%, that's usually where I start. Really hot engine, great afrs, open the bypass open a bunch, test mode IAC to 0%, the bring it down to 100-200 under target. Then you're not asking your IAC/MS's firmware to handle as much. Set your minimum to the lowest number it seems to effect idle, usually closer to 20-25%, and start tuning your initial duty for different RPMs/temps. I will say, TS's default temp table is 20-30-50-110-140. Even in frigid temperatures, you'll fly by the 20-30-50 range quickly, leaving you with effectively a 2x5 table instead of a 5x5. I find a lot of cars need one setting for the coldest local temps, one for a little under thermo temp, one at thermo temp, and one after excessive heat soaking. Something to play with.

mxteryman

The idle is working much better. Idle timing correction is done as recommended at -10/10 (I don't follow the rest, but that's OK for now). That plus a decent bump in the initial target values made a big difference. Also using PID activation.

It's getting dialed in, and at this point, under engine braking, 2k-4k and I clutch in (to brake and corner on the street) and I've had it drop to 500rpm and most of the time it goes up to 1300rpm and oscillates to ~600 and back and forth before returning to normal state. It is idling high, too, seems to be around 1050 rather than target of ~900-ish.

mxteryman

Edit: I will start a new thread, makes more sense. This isn't about idle - I don't think?