Min spark is stock. What I don't understand is how the PCM is arriving at a desired torque value.Originally Posted by 06300CSRT8
The log and tune of the car without any idle spark correction is attached. Thanks!
Min spark is stock. What I don't understand is how the PCM is arriving at a desired torque value.
The log and tune of the car without any idle spark correction is attached. Thanks!
Can you take another log with aircharge and total airflow logged?
Not that it should do anything to your timing, but I would marry up the top few rows of your WOT table to match your PT base table. Add a few rows or change the first few to be 34.7 and 44.7 kpa and copy and paste those two rows' values from your PT Base table. You're final timing is eerily close to your WOT table.
I have never tried to tune out the idle with the spark PID controller disabled as you have done.
Your Idle Torque throttle values are also a bit too high, your throttle body is jumping around from 16.9 to 17.3-17.5 on occasion, more than enough to cause a couple hundred rpm rise as it sits there. Try cutting your Idle Torque Proportional P/N in half, and cut the -516rpm column in half in the Idle Derivative P/N.
Will do.
I'm not really trying to tune the idle like this, I just disabled it to try and figure out what was causing the idle timing to be so low. I don't drive around like this. I can't really tune the idle until I figure out why the timing is so far below PT Base anyway.
When the car is warm it doesn't hunt nearly as much with the spark PID controller disabled. The RPM and consequently throttle voltage are steady.
Even after downloading the latest VCM suite I don't have any PID called "aircharge", so I just logged total airflow. The attached log is the car warming up with spark PID disabled, until it stalls. I'll post a log with my normal tune tomorrow (I actually meant to do that here, but I guess I still had the old tune on it).
Anyway, I'm assuming my VE or TB tables must be off, causing the car to get more air than its expecting?
Last edited by Grant; 11-02-2016 at 09:44 PM.
Here's a normal idle with the car warmed up and spark correction enabled (stock table).
Quick question with respect to the -1000 to +1000 scale on which side of zero is it adding rpm? Additionally if changes are made to that scale, for example reducing the ends from -+1000 to say -+500 would it only add or remove that amount to the idle swings.
Thanks.
-1000 means you are 1000 rpms below your desired idle rpm.
Adjustments will only max out at your min and max settings for each PID. Ending your table at a smaller rpm doesn't mean it will max out at that value, ex say if you are 750rpms below desired and stopped your table at 500, it will interpolate out to whatever error rpm you are at. Same idea with most tables in the tune, example timing and PE fueling, even without a rescale you can rev out past what you have defined in the table and itll still calculate what it SHOULD be.
So that I might have a better understanding of how this control works. If a vehicle is over the desired speed, you would increase the negative side of the scale to increase the torque to close the throttle. Which for a negative number would mean bringing closer to zero or even positive. Am I correct? Thank you.
First off unless you feel very confident that your over or under idling error is NOT caused by any airflow, spark, or fueling basic tuning, then this is not the place to tune out an over or under idle condition.
The tables are expressed in the direction of the change needed to arrive at your desired idle. The math is (Idle Desired minus Actual RPM). So a car idling at 1200rpms with a desired of 800rpms will be in the -400 section of the table.
Now the value to the right of that -400 is an amount of torque to subtract in order to arrive back at your desired. The PCM will convert these either to airflow or to spark, reducing either will reduce torque. Finally, for the torque throttle adapts, it will take the converted airflow and figure out where the throttle blade should be to arrive at that airflow.
If you are over your idle desired, but STEADILY over, then you have an underlying airflow problem. Adjust your throttle body airflow, large/small commanded airflow tables.
If you are swinging wildly above and below your idle desired rpm, THEN you may want to DECREASE the torque amount on either side of zero to make it stop OVER compensating.
Thank you for the information and instruction. Very helpful!
I don't know what you meant by the -516 rpm column, but cutting Idle Torque Proportional P/N in half didn't change the timing situation. It did smooth out throttle position.
I've tried messing with the Desired Throttle tables, with no luck. Increasing VE a lot seems to move timing advance closer to PT Base slightly, but it starts to run really rich (with > stock VEs, ridiculous for a cammed car) before there's any significant improvement. Changing the Engine Torque Model also didn't seem to do much, if anything.
I confirmed the problem is torque management related by zeroing out the Torque Management Spark Retard table. This makes Timing Advance = PT Base.
Last edited by Grant; 11-19-2016 at 10:58 AM.
The idle torque proportional P/N is a throttle body table, not timing related, sounds like you looked and changed the timing related one, which has only one column, the throttle body one has multiple columns. Part of your issue is you have both an airflow and fueling problem going on at the same time, so your timing is responding to those issues. Smoothing out the throttle body fluctuations will also help calm down timing.
Knowing if your engine is running rich is a total crap shoot, my car LOVES to idle at 13.5:1 on gasoline, but I know that is just the gauge reading rich from the overlap of my cam, inside the engine I bet its closer to 14:1, but impossible to know so I go by how it runs.
I don't get your last statement, the torque management spark table is your "floor" for timing, itll never go below that table, stock tune allows timing to go negative. I suggest to not allow that to happen, set it to somewhere around 5-6* in the idle area. Zeroing it out will allow timing to go close to zero degrees if your are idling too high, but that's it, should not have any further effect.
Oh wait a minute, you mentioned a different table.
You zero'd out the Torque Management Retard Table under the Torque Management tab?
Yes. This is the only way for me to get idle timing at or near PT Base; zeroing out the Idle Torque tables alone does not accomplish this. There seems to be something causing torque management to actively pull timing which is unrelated to any of the idle tables. It seems to me this isn't normal, and is a symptom of some other problem. I understand how PID controllers work, but I don't want to try and really dial in the idle until I figure out what is going on here.
I guess I'll try decreasing throttle angle at idle by altering the Desired Throttle tables beyond what I'd consider normal values. It could be my Arrington TB doesn't mimic the stock angles for a given voltage as many suspect.
If cam overlap caused unburnt fuel/air to enter the exhaust which was not hot enough to ignite it, wouldn't this cause a lean reading? Similar to how WBs read lean during misfires?
Unfortunately my motor shipped with what I can only describe as the wrong cam; a 224/232 on a 449 cid motor. I plan to replace it this winter.
Last edited by Grant; 11-22-2016 at 11:43 AM.
Yea sorry I didnt describe that right at all, I command 13.5:1 so that the o2s see around 14:1 AFR. If I didnt do that they would be reading much leaner and reading false lean, add fuel, and make it run like poo.
And yea that cam is way way too small for that motor. My 426 has a 235/251, loves it, winds up to 7k still making power.
idle is good but it dies after reving in park. it idles at commanded idle speed fine but after a rev, it slowly comes down to idle speed and continues on down till it dies
Post tune and log for HELP. Then able to see whats happening and maybe Why
I know this is an old thread. I have been making my eyes bleed reading and learning. Trying to play catch up. But in my understanding of this could this be used within reason to control the aggression of a cam at park an neutral? For example make a cam idle more or less choppy ( within reason of course ) I have seen the LS guys use similar settings to achieve this.
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