DIYPNP NA Idle setup
 

I installed my DIYPNP this last weekend and got it to start up with a 1994-1997 1.8 base map from here: MegaSquirtPNP by DIYAutoTune.com

I haven't driven the car yet, I've just set base timing and tinkered with idle and AE a bit. I've got my idle algorithm set to open-loop warmup right now and it seems to be fine... until it warms up at which point is settles to ~740rpm and idles rough. I'm trying to figure out how to get it to idle around 850ish as it should. Options I've read about are adjusting the idle stop screw and going to closed-loop control. The latter seems to be the right route in my opinion, but people keep saying to spend the time to tune open-loop first.

So I have to ask, do the two algorithms; open-loop and closed-loop work together at all? Does MS know to run open-loop until its warmed up and switch to closed-loop? Why else would I waste my time with open-loop settings?

No you can't switch from open-loop to closed-loop when it is warm.

You need to raise you idle duty value a bit when warm to get it to idle higher the 740rpm. Also what afr are you at when it idles rough?

when warm set your idle with with the idle screw. in closed loop the valve will take care of changes in load/atmospheric conditions

omfg. USE CLOSED LOOP IDLE.

im a little shocked they setup their basemap that way. I would also do myself the favor up upgrade to the 3.4.2 release.


regardless, you didn't tune the warmup idle duty table well, because the idle valve basically stays locked at the last value on that chart -- if youre dropping to 750rpm, it's cause you've tuned it to do that. Even the warmup table in that basemap isn't great.


you should have followed my DIYPNP installation guide and used my basemap that should have you idling perfectly on first crank without any tuning necessary...

I would have but your avatar gave me a seizure and I suffered memory loss and disorientation... Thanks for the tips, I'll swap the tune tonight and see.

:rofl:

Just reiterating that you should update the firmware (idle code is much better) and then read a few guides on tuning closed loop. It's not too complex and it really is the best option.

I just did my first DIYPNP and had similar problems. Went into CANbus/testmodes to get closed loop idle valve closed/open valves. base map values were way off. CL idle is smooth now

Thanks for the input, guys. My firmware is up to date, it's just that I couldn't find a more recent base to start from until Brain mentioned he had a 3.4.2 map available at trubokitty. Brain's map was set up for 550cc injectors so I had to update that for my setup, then set base timing, and up the fueling VE table around the idle region because it was idling around 14.5 (his may have been set up for sequential fuel).

so now it idles at just over 800rpm, ~30kPa, and ~12.7 AFR. It probably still needs tweaks for my specific setup but overall it's much better. All hail the Braineack.

but why did you tune it to idle at 12.7 and not 14.5? 14.5 is like SPOT on...

also becareful all your inputs and outputs match how my tune is setup -- like the fan control for one.

Yeah.... So I did a few things: first I fixed the fan output, which I had missed. So fan turns on now. Then I saw I hadn't switch to Untimed Injection, so I changed that. I haven't driven it except for around the neighborhood but it seems to run the same whether set to untimed or semi-sequential... I'll have to learn about that.

I also switched the Fuel VE values back to what Brain's basemap were (I had only adjusted 4 idle region boxes), then I calibrated my IAC duty cycle steps. My lower and upper limits turned out to be 24 and 60, respectively.

at this point it was idling pretty good, around 13.8 afr and 820rpm. I bumped up the close-loop target RPM curve so now when the engine temp is at operating temp (~90C) the car idles at ~950rpm, same as before.

semi-seq. and timed injection is techincally better if you setup the table. I dont think my 90-93 map has it setup, which is should...i can update it one of these days.

I would give the idle a B grade right now. I'm limping it around town to burn out the 87 ACN gas to fill it with 91. Brain, is there a reason your basemap timing table kpa range is 19-225kPa, and your fuel VE table is 20-101kPa?

i uploaded the wrong basemap? :P