Idle spark is causing the spark to move. Try this in the under under idle spark control. OR just zero them out completely to rule them out. I guess 30* is coming because you have high 30's values in the 1200RPM column of the two idle spark tables, and thats where it falls when interpolated. We know it wants 24-26*@900RPM, so that may be sending your idle high. Adaptive and IAC are fighting it, causing the back and forth.
Got those numbers into the new Tune and wrote it to the car, it's seemingly better although still surging as it warms up. I'm attaching the Tune and the Log.
MixTune with your suggested changes
Start up to Operating Temp
1:22 Warm up ended, RPM to 1500/2000, then Switched into Gear
In between this post and my last one I pulled all the vacuum hoses out and made sure there were no holes. You can see the MAP moving but I'm thinking that's attributes to the airflow, with my foot on the brake it would push it back every time it idled up.
I still see the spark jumping, but setting those tables should have corrected for that, shouldn't it? You were saying earlier that if I zero it out then I might get a better result, what would be the suggested action?
Also it seems like when the engines off you are at 0% throttle, once it starts it goes to 0.4%, probably doesnt make that much of a difference, but if you can adjust the set screw while the engines running to get it to 0% throttle with the engine running that would be best.
Got the throttle to show 0.0 after adjusting the idle screw while it was running and copied over all your values, it seems to be running a little worse now after zeroing out those over/under tables.
Attached we have the tune, start up log and idle - 3000 rev logs as per your last few requests. I can't make heads or tails of this now, It seems like the spark is exactly where we want it, but it's still surging like crazy trying to stay alive.
Tune and your recommended changes
Start up cold -> Operating temp
Idle - 1500 - 2000 - 2500 - 3000
Still the IAC is moving too much. Lets try making the RPM error window for airflow PID bigger. Cams will naturally surge a little, but not like what you are seeing. Once we find what makes the IAC stable, the over under tables can go back to the first way I suggested.
Still seeing the same thing with those changes, I just had it cold and up to operating temp, and here are the results. The idle seems to be great while getting up to temp, but as soon it crosses that threshold then it just starts to go crazy again, with the RPM surge. I will say it doesn't sound like a cammed car and feels more like it's just trying to get enough air to stay alive. Would upping the Base running airflow make any difference?
Here is the Tune and the Log, let me know what you think.
MixTune, per your suggestions modifying the RPM Error
Startup cold to Operating Temp log
Your effective area table isn't calibrated for the new tb, its throwing off your base airflow. Your idle spark looks high and it humps over from 25-28-22 where its trying to settle.
Murfie, I added 2g/s and it's still doing the same thing. Something else has to be up with the spark tables, we've eliminated anything else adding spark, do you think it's caused by the HO / LO Tables now? I'm attaching the standard logs, and tune with the Running Base Airflow. What would you say is the next step, the spark is essentially dialed in at the place we want it and it still is having problems staying alive.
curiousg7, this is actually the stock LM7 throttle body, and this tune started out with a 2000 Chevy Silverado 1500 tune, do you think it's off?
Attached:
MixTune - Added 2g/s Base Running Airflow
Log from Cold to Operating Temperature.
Ok, so I modified a few things that were pointed out. I went back and referenced the IAC Steps vs Effective Area and they were off from the stock LM7 engine, so I put those new numbers into that table, then I set the base running airflow a little higher .50 only. Logging Desired Air vs Dynamic air it seems the Base Running Airflow is still a little high, but I'm not sure if I should drop it. The car is still surging pretty badly which I'm not 100% sure what's causing it. As I said before this only happens when it hits 55ect, not sure WHAT exactly that means as I'm a complete beginner to this.
Overspeed and underspeed are still zero'd out, should I go ahead and adjust those back to previous values now that we can confirm that we're pulling the right amount of spark?
I'm going to attach the tune and a log as per usual, please check them out and let me know where I'm going wrong here.
Attached:
MixTune with the modifications listed above
Startup Log from Cold -> Operating temp
One additional thing not to take away from this tuning process, but if I wanted to take another tune (From the repo) and start from scratch, how do I go about doing that. If I flash another tune over it would it cost me another two credits, or does the License stay with this specific ecu? I've just been modifying the tune I pulled from before but I think that might be half the cause.
Alright so your fairly close i think. In your base airflow copy and paste the average dynamic airflow value for each temperature break point you have logged. Then make desired airflow match dynamic airflow in the log. You can do this by lowering your effective area to make desired go up or raising it to make desired go down. Yours seems too high. maybe from adjusting tb set screw.
The spark is close id try like 17-20 and see where it likes to settle
curiousg7
We did of tuning for this spark and from the data gathered previously it seems like it wants 26-28, so that's what it's at right now with overspeed and underspeed zero'd out, and as far as the airflow I've run Russk's config for airflow, although it's been modified a bit since then it hasn't changes drastically. I have messed with the set screw alot during my 'reset' procedures, I should lower it down completely again and let it relearn from a base setpoint instead of something as high as it is right now. I'll try the tune with the different airflow values shown in the log and see what I can come up with. Will update as soon as I can get some of those numbers.
murfie
I'll get on that when it's nice and cool again, most likely in the morning or wee hours of the morning as it stands. Any thing I'm looking for when it comes to the logs to make sure everything is still good?
Procedure: Start car, unplug IAC, wait until operating temp is what I'm going to do, let me know if that's not proper.
Ok, got a run from cold to operating temp, with the IAC unplugged and here are the results. The IAC Seems to be working as expected, but please correct me if I'm wrong here. I pulled a fresh tune from the car just to make sure we're capturing everything and here is the latest tune and log for the start up.
Let me know what you think.
Tune - Fresh pull with murfie suggestions
Log - Cold to Operating temp with IAC unplugged.
What you see in the log is the IAC command, not the actual position as the IAC isn't moving when unplugged. With spark set steady, and IAC unplugged that just leaves fuel rail pressure or injectors causing this surge. Spark, air, and fuel. Which makes since when the surge starts is when it goes from OL to CL and starts using the O2 sensors as feed back. We were having to lower the MAF curve to meet the ratio, the actual injector flow rates were lower than what was in the calibration. This is caused by Low fuel rail pressure, put a gauge on it and check to make sure you are at 58PSI. A wideband in this situation would be very telling.
If you want to try making it so the idle fuel CL just doesnt overreact you can try lowering the prop. and int. error adders, at idle your airflow is in mode 3-4 from cold to warm. These PID/ adaptive tables are things you shouldn't have to change.
Ok, those changes made it worse, the surging is louder and it's dropping lower in the RPM range during each surge. I have a fuel pressure gauge on the rail and it's showing 60-62 psi, not dropping below 60 at all. So fuel pressure seems good for what I'm looking for. Here is the tune and logs that are showing the changes, and outcomes.
Attached:
MixTune - With your suggested changes
Log from Cool -> Operating temp, it shows open loop and then getting into closed loop as you were saying.
I have the wideband, but need to get the bung welded on, with it surging like this I can't get it to a shop to see where the fuel pressure is. I could go back to my old tune and then pick up where I left off, but I think that would be really counter productive. But I'm really open to suggestions, what do you think would be next?
It wasn't surging on the first tune you posted, so go back to that and if it was a change we made is should be better, I'm not sure what change would cause that.
Surging at idle at temp? I didn't see it in the first drive/ second drive logs, not until the first spark step log. At least nothing as obvious as it is now. Spark not being smooth and jumping too high too fast is usually what people experience as surging. I think the only changes were your power enrichment and base correction fuel spark correction table, both which shouldn't even be used at idle.
With the airflow steady, the spark steady, the RPM should be steady or as steady as it can be. The only thing left moving is the fuel, and it would have to be moving a lot. Forcing open loop and tuning to what a WB says would be the next step.
You can try going back to stock on the integral delay airflow mode. Then instead of reducing the Idle proportional, increase it to 64 from 0-4.
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