Hi

I seem to be having some difficulty setting up how CL idle control comes on. I'm watching my PWM idle settings and it sits at about 35 initially, then after a few seconds for a reason I can't fathom, it will drop to 27 (which is where I have my target lookup table). I don't think Closed loop idle is activating, or it only activates for a short period and then turns off.

Thanks in advance for any help.

 

Most likely you are seeing that 27.x at 1400rpm (from the base table) , plus the 7.x in the dashpot adder (27.x+7.x=35.x, followed by a rapid decrease to the correct value of 27, which is done by closed loop. It is rapid because the closed loop function is set very very aggressive. Your slider is 80% along the high end of the scale, I run them at around 10%.

The ecu also has a setting seen below called 'PID ramp to target time". This is how slowly the ecu tries to make engine speed go from liftoff to your commanded rpm as seen in the "closed loop idle target" table. So the ecu will actually use the values for 1600, 1400, 1200 1000 etc over the course of 2 seconds. You are seeing it use the 1400rpm cell on the initial value table and then before it can ramp down further using the 'ramp to target feature' immediately go into aggressive closed loop and drop to the correct 27% because this process takes over 2 seconds on your setup.. This is higher than your 18% values because by now the ecu has taken over using closed loop and it doing it on its own. Remove the dashpot adder, reset these values to the correct ones, and lower your closed loop slider down to 20% of the bar or less.

 

Thanks, I finally got a chance to try out these setting - HUGE improvement, thanks very much. Dropped Dashpot adder down to 1.2, Dropped slider bar to 10%ish, Dropped PID delay and PID ramp to target down to 1 sec each. I'll probably need to keep tweaking but this has put me on the right track, Thanks again

 

 

Idle seems to be fine now, thanks, but I'm having problems with it cutting out when I come to a stop - sometimes. looking at my data log I have two time I pulled over - 1st one it all works fine (@20secs), PWM idle come in and car idles fine, 2nd one (@ 38 secs) the PWM idle does not start until too late and the car dies....I also see PWM idle doing things during driving - is this right - should it being doing this ?

Thanks !

 

8% dashpot adder is insane.

using MAT for lookup table is insane.

 

your max decel load is 20%.

coincidentally your idle valve doesn't open until you hit 20% load and increases again...


and your intial values table are all over the place.

youre using timing advance (static)...


and youre not using idle ve table.



youre setup to fail...

 

Er thanks. I recognize I'm not sure what I'm doing, thats why I posted, care to help me out with some suggestions for how to fix this mess ?

 

well, I kinda gave you a freebie with that first one.

you will never get into CL idle if you never hit the max decal load % number. 20% load is VERY aggressive. You want to set that value just under where you normally idle at, so you go into CL idle without having to pull so much vacuum. if you normally idle at 32kPa, I'd set it around ~28kPa. Currently, if you don't actually hit 20%, CL might not activate, and the valve might not open to your intial value, and just stay at 18% -- which is not high enough to maintain idle, and stall.

Related: Aggressive overrun values are a similar concept. If you don't return fuel until the last possible second, there could be a dead spot where no fuel is being injected as the ecu is trying to open the valve and increase the load to maintain idle. the car will simply stall in that case.

also related: you should mechanically tune your idle speed valve so the car doesn't stall with the idle valve completely shut -- but maybe sits around 600rpm or so. this is a two-fold thing. 1. it will prevent stalls in the cases above. 2. it will give the valve enough working range for both summer and winter air densities.

your initial values table is the %PWM the idle value opens to when it goes into CL idle. Your values don't seem to make sense and jump all over, that table should look very smooth and predictive. The table should basically be an Open Loop Table that could perfectly drive the valve at the given conditions in the table. You should use test valve mode, or even warm-up only mode to figure out good pwm% values to fill the table up with. CL will use that value as a jumping off point to open the valve up to initially and then go from there.

you have both timing advance (static table) and adaptive timing control on. I'd have to look at the logs again to see if that matters, but IMHO both shouldn't be able to be active at the same time. turn of timing advance and only use adaptive timing control -- your table for that looks fine. This feature watches if your rpm drifts from the rpm target and advances/retards timing in order to keep it in line; this works much better than trying to open/close the idle valve to compensate -- where the CL idle code will just keep it in the relative position it needs to stay at.

VE idle table is simply a much better fuel map to use at idle IMHO -- the more stable your AFRs are at idle, the easier your idle will be to control. You tune idle control if your AFRs are a mess at idle.

 

Why is your Stoich AFR at 14.1?

 

Thanks for all the help, very much appreciated. So I tried all you suggested, so far it seems to be ok, i need to drive it a bit more now, but my idle is around 25-6 ish kpa which seems a long way from your 32kpa and I need a ton of fuel to keep idle stable. I bumped up the load to 23...still seems like that might be aggressive - but based on my idle load maybe OK ?