Idle tuning - Megasquirt 2 + TSP 228R + Milled 862 - LS1TECH - Camaro and Firebird Forum Discussion

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Idle tuning - Megasquirt 2 + TSP 228R + Milled 862

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Old 06-01-2018, 09:20 PM
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Default Idle tuning - Megasquirt 2 + TSP 228R + Milled 862

Hey guys,
I'm new to learning tuning, but am feeling overwhelmed with the information. Right now I'm trying to get the idle tuned on my LS.

Engine is a 5.3L fresh rebuild, dished pistons with -8cc dish.
Removed swirl ramp from heads, and removed rocker bump. That's all the porting.
Had heads milled .030".
New push rods 7.375" with LS7 lifters.
Cam is TSP 228R 112 LSA.
Injectors are 450cc injectors @ 3 BAR, [email protected] (~52 lb/hr @ 58 psi?)
GTO T-56.

Alright, so, i'm having issues getting it to idle with my megasquirt 2 board. I can technically get it to idle around 1.1k-1.2k RPM, but i've been trying to bring it down into the 750-850 range.

Is there anything special I should know about getting this cam to idle well? I've read some saying 20-22 degrees of timing to get it to idle well, and a 13.0-13.5 AFR. I don't have knock sensing capabilities with my MS2.... so, I worry about messing with timing too much. I'm hoping to have a solution to the knock sensing later on, or some method to listen for it. I've heard it's not as bad at low RPM, it's high RPM, high load that can destroy the engine?

I am tuning with IAC closed and plug removed, and system set to open-loop mode.

Is there a general region that the base timing should be at for this setup? My kpa load when trying to idle, appears to be sitting 60-70 kpa. If I have the throttle held slightly, to hold the car at 1k RPM, it sits at about 50 kpa.
I'll attach my newest tune attempt and log. I added a ton of timing (right terminology?) to 50-80 kpa @ 700-1k RPM zone. due to someone mentioning 20-22 degrees at idle. But... it was previously ~16 degress.

Tune:
https://drive.google.com/open?id=1mQ...BSGnNl2LU044Pk

Log:
https://drive.google.com/open?id=1em...6nMs3CbwPRAmaJ

Still reading as much as I can. Just wanting to try and get a relatively consistent idle @ 750-850 RPM.

So much to learn, thanks!
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Old 06-02-2018, 07:59 AM
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Alright, so disregard that tune and log. I spent a while digging and found a few errors in the tune.

I've adjusted, and will hopefully be able to provide a new log and tune.

Still looking for general tuning advice on the setups idle. I'll eventually get dyno time and tune that way.
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Old 06-02-2018, 11:19 AM
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You need to try and lean out the AFR to high 14s and try timing around 25 degrees. I would also unplug the IAC and adjust the throttle set screw until the car barely idles/stalls.
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Old 06-02-2018, 04:32 PM
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Thanks!

So much information out there. Somewhere i read 13s for AFR.... ugh.

I'll try and get it closer to high 14s and timing in the 25 area.
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Old 06-02-2018, 06:41 PM
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It's sitting around 800 or so idle now. It does sometimes seem to jump up to around 1.2k and back down, and sits for a little.
Not sure what would cause it to hunt like that?

I'll get log and tune posted up. AFR still not where I want it. I did notice, as I go leaner in some areas, it causes it to idle up higher.

I don't have the right tool to adjust the throttle screw while the throttle body is on... trying to get under the throttle body with all my current tools isn't happening. Too big.

I'll try and get a video tomorrow as well as some log data. Current exhaust isn't good enough to keep running constantly. Getting smoked out.... and, trying not to die. HAHA.

I did check temperatures on long tube headers, each one showing mostly the same. Hotter towards the back of the engine. But, the front 2 are showing almost 20 degrees cooler than the back ones. Is that normal?
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Old 06-02-2018, 06:45 PM
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You'll have to play with the idle learning tables as it may swing too much when making changes. Surging is typically from a combination of too rich AFR, too little timing, not enough idle airflow.
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Old 06-02-2018, 09:46 PM
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Thanks! I'll keep at it. Sounds pretty nice as it's getting to idle. hahah.

adjusting the throttle screw is the most annoying. I really need to get an angled t10
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Old 06-03-2018, 07:47 AM
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Originally Posted by Rx7TyreBurna View Post
Thanks! I'll keep at it. Sounds pretty nice as it's getting to idle. hahah.

adjusting the throttle screw is the most annoying. I really need to get an angled t10
The other option is take the throttle body off the car and take the screw completely out and thread it in from the other direction. Now to adjust it you just shut the car off and turn the throttle blade to access it.
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Old 06-03-2018, 09:02 AM
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After looking at your tune you posted there is a lot of things wrong in there. I see that you found some errors in there but not sure what all you found. Hopefully under general settings you changed your stoich to 14.7 and you just use tps based ae. EGO is set above your idle also if you are planning to use it down low at idle I dont
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Old 06-03-2018, 10:24 PM
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Grabbed an angled T10 at the store today (actually a nice set for cheap). Funny, i'd thought of yanking it out and putting it in the top previously, but wasn't completely sure if that'd cause issues. Plus, I see where being able to adjust it while car is on, is nice.

Thanks rt338b! Yeah, that tune had a few things off. my current tune is attached to this post.... What do you mean EGO? For AE.... I believe my current tune will show 50/50 MAP / TPS.

Right now, When i start it cold, there it isn't smooth at all. Very rough, and I had a loud pop from the exhaust. But, as it warms up, it starts to idle smoother. I think I have the throttle plate screw set correctly now. Also when it's warm now, if I blip the throttle, it'll rev a little and come back down and settle in the 800-900 range. But, it's still hunting some. I'll see it jump 850, then 700, then 900, then 800... so, I know i've still got a bit of tuning to figure out.

I also realized, I never hooked a timing light up, to verify (offset?). So, I need to get a piston stop, and do the TDC thing, then grab a light and do the offset timing. I was watching a video of Matt (Can't think of last name.... sloppymechanics), and in his video showing how to do it, he had a 6 degree offset. That seems pretty significant. And, I wonder how far mine is off.

Appreciate all the knowledge guys! Learning as quick as I can, with the time I can get.
Attached Files
File Type: msq
2018-06-03_20.16.39.msq (116.1 KB, 2 views)
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Old 06-04-2018, 10:28 PM
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Alright. Ran car for a bit. I think my tune got way too far out. I had more than a couple loud bangs from the exhaust.
I also heard two big loud bangs from what sounded like the intake manifold. I don't see any damage on the manifold, but I think timing was all messed up.
I think i'm going to wait until I get the timing light, and get the offset setup. I suspect maybe the timing isn't completely right.

I set my timing table back to what it initial was, back before i messed with everything. And, set the fuel back. It was way too rich, so I leaned it out.

The attached tune... i found that I had required fuel at 10.8, but the calculator originally put 9 there. I changed it to 10.8 some time ago. I put it back to 9, and added 10% to the idle area. That won't show in the attached tune, but I did change it. I'm attaching tune and log from when it was idling for a while without issue. Still in the 900-1k range, but I'm going to try and reduce the throttle opening a little bit to see if it will drop.

I haven't looked through the log file yet, but i did notice the PW mentioned earlier not being very constant.
Attached Files
File Type: msq
2018-06-04_20.19.04.msq (116.0 KB, 2 views)
File Type: msl
2018-06-04_18.52.16.msl (142.0 KB, 3 views)
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Old 06-04-2018, 10:50 PM
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I suggest messing around with adaptive idle if you want it a little more consistent.
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Old 06-05-2018, 09:24 AM
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Thanks JoeNova. Where is adaptive idle in TunerStudio?
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Old 06-06-2018, 09:21 PM
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Ran some idle tonight. I'm occasionally hearing a loud pop from what sounds like the intake manifold..... it happened twice when it was really cold, then once when it was warmed up. Being in the car, I'm not sure if it's the intake, or what.... sounds like backfire on the intake side though. I am running wasted spark... so I'm curious if there is unburnt fuel that is firing on the second spark ? .... or if there is maybe a hot spot and when the intake valve opens and fuel comes in, it's causing ignition inside the intake? I'm not seeing any damage or anything around the intake, and... an ignition event inside the intake would show on the MAP sensor, right?

Log and tune for that log are attached. I haven't fully analyzed yet, but AFR seems better, and I have idle timing ~20 degrees. I was changing it and making it higher, in hopes to stop it hunting up and down. It's hunting less, but it's still there. I don't want to mess with timing too much until I get a timing light out, and verify timing.
Attached Files
File Type: msl
2018-06-06_19.03.07.msl (206.7 KB, 5 views)
File Type: msq
2018-06-06_19.03.12.msq (116.0 KB, 4 views)
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Old 06-06-2018, 10:53 PM
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I just downloaded MS to view that. that is proper old school.

youre targeting a 15.2 AFR at idle by your target AFR table? I would target a 13.5-14.0 idle AFR with a decent camshaft. all the other values above 14.5 change to 14.5 and leave the rest as it. this should make it easier when it comes time for closed loop fuel learning.

intake pops are usually an indication its lean, or the dizzy is 180 out lol.

I would target 10-12 degrees at idle. with no IAC you're probably going to have to have a higher idle RPM to prevent stalling on return to idle. just set your idle timing to 10-12 deg when its warm and 13.5-14 AFR and adjust the throttle blade until you are at about 900rpm. you'll likely have to hold the throttle to allow it to run while its cold but just get to operating temp and then do the above,

because you have no IAC the only way you can correct idle RPM drift is with timing. with a big cam its going to drift no matter how good you are.

to do this enable idle RPM advance timing. then populate the table as follows or close too. 600rpm 20* 800rpm 17* 925rpm 12* 1000rpm 10* 1100rpm 9*
this will add timing to increase rpm when it falls away and remove timing to reduce rpm if it climbs.

that will take a while to get right and will likely take some adjustments. with no IAC you need to be sure the TB can flow enough air past the closed blade to stop the engine from stalling when you free rev or slam the throttle shut using only additional timing advance to stop RPM dipping below idle.
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Old 06-07-2018, 06:55 AM
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EFI source sells an IAC controller for micro.
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Old 06-07-2018, 07:22 AM
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Originally Posted by Luke19901 View Post
I just downloaded MS to view that. that is proper old school.

youre targeting a 15.2 AFR at idle by your target AFR table? I would target a 13.5-14.0 idle AFR with a decent camshaft. all the other values above 14.5 change to 14.5 and leave the rest as it. this should make it easier when it comes time for closed loop fuel learning.

intake pops are usually an indication its lean, or the dizzy is 180 out lol.

I would target 10-12 degrees at idle. with no IAC you're probably going to have to have a higher idle RPM to prevent stalling on return to idle. just set your idle timing to 10-12 deg when its warm and 13.5-14 AFR and adjust the throttle blade until you are at about 900rpm. you'll likely have to hold the throttle to allow it to run while its cold but just get to operating temp and then do the above,

because you have no IAC the only way you can correct idle RPM drift is with timing. with a big cam its going to drift no matter how good you are.

to do this enable idle RPM advance timing. then populate the table as follows or close too. 600rpm 20* 800rpm 17* 925rpm 12* 1000rpm 10* 1100rpm 9*
this will add timing to increase rpm when it falls away and remove timing to reduce rpm if it climbs.

that will take a while to get right and will likely take some adjustments. with no IAC you need to be sure the TB can flow enough air past the closed blade to stop the engine from stalling when you free rev or slam the throttle shut using only additional timing advance to stop RPM dipping below idle.
The bigger cam will have more natural EGR, aka less torque at idle. It needs more torque to stay idling so 10-12 degrees at idle on a cammed setup will not run well at all.
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Old 06-07-2018, 07:48 AM
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The cam in my 4.8 only has 9 degrees of overlap, and it won't even stay running below 900 RPM with only 10 degrees.
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Old 06-07-2018, 09:00 AM
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Wow, thanks for the information Luke. And I appreciate the input from ddnspider and JoeNova as well.

I'll keep playing with ignition timing, but I think i'll wait until I make sure it's actually correct in the PCM. Due to there being a setting for ignition offset, and I haven't calibrated that yet. But, once it's going, I'll try both 12 degrees, and higher timing as well.

It does have an IAC. I just have it disconnected for now, to get the base idle setup, and then will utilize the IAC to help with idle when it's cold, or if there is different loads on the system during idle.

I'm curious about the intake pops, due to timing, and wonder how far out my timing is. Being that it does wasted spark... I'm curious if the firing is maybe firing a little incorrectly.... When i get a timing light, and force timing to hold at 10 degrees, I'll verify timing and adjust.

I'll be on vacation for a week coming up and won't have access to car or computer.... so, it'll be a little until i can check and reply. But, I appreciate all the information and attempts to teach.
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Old 06-13-2018, 10:28 PM
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Tune + log attached.

Finally got timing light, and TDC figured out. System was off by 6 degrees. So, I got offset at 6 degrees now. Not hearing popping intake anymore, or anything like that. I did have to reduce my warm-up enrichment, as I was getting to 11-12 AFR on warm-up. I'm guessing I should be shooting for ~13 or so on warm-up? Or, leaner on warm up?

What's the best method for determining max advance at idle? I've been tuning fuel, then adding a little timing. Leaning it out... add timing.... adjust throttle plate screw, repeat. I'm adjusting throttle plate screw to try and get the idle a little lower. Right now, I'm sitting mid to high 14 AFR, and timing at 28 degrees. This seems like a lot to me at idle. In the tune, I'm blasting the area I am seeing the car idle around, until I can get a more consistent 4 block or so idle zone, and then I'll interpolate from there.
What I've seen, is that as I close the idle plate a little, maybe 1/4 turn each start.... the AFR goes down, so I lower the fuel, get it back into the 14s and then add a little timing to try and stop it from hunting around. Is adding timing a degree or so at a time a good way to get it to stop trying to hunt? Once AFRs are in the 14s.... do I just slowly add a degree at a time? And... without a knock sensor, are there signs at idle that there is knock, or that I've put too much timing in?
It'll sit and idle 850 or so for a little bit, then jump to 1k or so, then back down.
Starting on some advanced tuning books, and I'm trying to get it all figured out.

Appreciate with everyone that keeps following this and trying to help out. Slowly but surely I'll get there. hahahah!
Attached Files
File Type: msq
2018-06-13_18.05.38.msq (116.0 KB, 1 views)
File Type: msl
2018-06-13_18.05.32.msl (276.2 KB, 1 views)
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