THE Most Powerful and Neglected Tables in the LNF E69...

[silverbullet08]

Well it didnt have anything to do with the tune. It was a combo of two things. My factory boost control solenoid took a dump for starters which made the problem worse, not sure if that was related to anything. The other issue was man made. I ordered a new filter for my big turbo set up and it hadnt made it here yet so I clamped a microfiber cloth to the intake tube and put a squirt of k&n filter oil on it "yea pretty ghetto I know" but i figured it would just make due for the time being. Well evidently it was too much restriction. I took the cloth off and boost went straight to my spring pressure in my wg. Well guess I can get back to this idle tuning mess lol.

[articzap]

Just started working on my friends car last night and things are going very smoothly.

But a question, should the 4 optimum spark tables be the same or just making similar changes to all 4 tables? My guy tells me all the same, but I don't know for sure.

[stromboli86]

you can make the 4 Main spark tables the same but i havent heard of anyone making the optimum spark tables the same, just make similar changes.

[Freakotec]

Definitely do not make all of the optimum spark tables the same.... There are areas that can be close in areas across all of the tables, but do not just copy and paste the tables across the board.

[stromboli86]

So far this is where i am at after 3 flashes... spark averages about 12*, steering wheel is noticably smoother at idle(makes A/C on at idle feel like a brute!) altho my timing isnt a flat line quite yet im pleased, and my commanded throttle angle is 1%! Something else i noticed is my MAF lb/min has gone from .42 down to .35. Good stuff!

[projectlnf]

i tried this the other day and the closest i got was 17* and it surged like hell when i had ac on but it idled ok it had a low spike of around 12 and it would get rough then smooth back out i have everything back to normal now i was planning of fooling around with it over the weekend. ill post a log if i have problems

[Dayhoff35]

mess with your airload a little bit

[Freakotec]

^^ How do you have yours looking at idle man? The best luck I've had with mine thus far is actually setting them a decent amount lower than stock.

[silverbullet08]

almost there... I also made a pretty cool discovery last night.

[gmtech16450yz]

Looking good!

I was talking to my son about this stuff yesterday and trying to explain to him how some of the tables interact. It's pretty crazy. Did you guys know that if you raise your ign timing in a certain cell in the main timing tables that it can lower your throttle opening at that same situation? Totally true and repeatable. The reason is that these Optimum Spark tables are comparing that requested ign timing to what value those numbers should give as far as torque output. Higher ign timing tells the Opt Spk table that it's making more torque than it needs, so Opt Spark lowers ign timing back down. When it can't lower it anymore, it lowers throttle opening. That's part of why the idle tuning is difficult, give it too much ign timing in the main tables and the throttle won't be able to give it enough airflow. Opposite is also true, crank up the Opt Spk numbers and it will end up opening the throttle too much at that point. Opt Spark tables have a HUGE effect on throttle plate vs. pedal position. That little tidbit is VERY important when it comes to guys trying to tune by their butt dyno or even by logging. You absolutely have to be logging pedal position vs. throttle position to see stuff like that. You can give it a ton of ign timing and the engine might feel slower actually, even though it's not. It's because the torque based ECM is trying to keep the power at a certain level, no matter what you do that might be raising power or efficiency. Tricky huh?!

Those that are trying to figure out this stuff should probably read what I just wrote above a few more times! That and what I've said a few times about idle being a balance between ign timing, throttle opening and fuel mixtures. They ALL have to be within their range of authority so that they all can work together. Get one too far any direction and they'll just fight each other, which most of the time ends up as surging.

Sorry it's been a little frustrating for you guys, I tried to warn you all! This stuff is not easy and the table interactions are very difficult to figure out. The good thing is that if you do figure it out, you'll have WAAAAAYYYYY more control over your tune than anyone tuning these LNF's has EVER had. These E69's that GM and Bosch gave us are extremely powerful ECM's, they're just very, very different than any other ECM.

Keep at it guys! And SB08- Discoveries are what makes me enjoy doing this stuff so much! You can beat your head against the wall for hours or days and then all the sudden you figure something out and it's like Christmas! Sure makes me feel good when I make a new discovery, and I'm still making them constantly on this tuning stuff.

[Freakotec]

almost there... I also made a pretty cool discovery last night.

Wow man. What is going on with your maf in that log if you don't mind me asking? It's showing that you're flowing a TON of air at idle and at a crazy high frequency. Something going on there that I'm missing?

Looking good!

I was talking to my son about this stuff yesterday and trying to explain to him how some of the tables interact. It's pretty crazy. Did you guys know that if you raise your ign timing in a certain cell in the main timing tables that it can lower your throttle opening at that same situation? Totally true and repeatable. The reason is that these Optimum Spark tables are comparing that requested ign timing to what value those numbers should give as far as torque output. Higher ign timing tells the Opt Spk table that it's making more torque than it needs, so Opt Spark lowers ign timing back down. When it can't lower it anymore, it lowers throttle opening. That's part of why the idle tuning is difficult, give it too much ign timing in the main tables and the throttle won't be able to give it enough airflow. Opposite is also true, crank up the Opt Spk numbers and it will end up opening the throttle too much at that point. Opt Spark tables have a HUGE effect on throttle plate vs. pedal position. That little tidbit is VERY important when it comes to guys trying to tune by their butt dyno or even by logging. You absolutely have to be logging pedal position vs. throttle position to see stuff like that. You can give it a ton of ign timing and the engine might feel slower actually, even though it's not. It's because the torque based ECM is trying to keep the power at a certain level, no matter what you do that might be raising power or efficiency. Tricky huh?!

Those that are trying to figure out this stuff should probably read what I just wrote above a few more times! That and what I've said a few times about idle being a balance between ign timing, throttle opening and fuel mixtures. They ALL have to be within their range of authority so that they all can work together. Get one too far any direction and they'll just fight each other, which most of the time ends up as surging.

Ok maybe I'm doing something completely wrong here then. I've tried 1.573 MILLION different combinations (lol) and so far the thing that seems to work the best for me so far (although not perfect yet) is alot of commanded idle timing in my main tables (32*), lower than stock dals, and obviously increased idle timing in the optimum spark tables. I found the further I lowered my commanded timing, the worse she wants to idle. I tested as low as 15* (main timing) and attempted to adjust everything else work around that with absolutely no luck. So what exactly are you commanding at idle in your main spark tables if you don't mind sharing? I've got things relatively smooth, but not quite as well as I'd like them to be really.

My timing is definitely still bouncing around on me but at least my trims have settled down a bit (although they do still wander around a little more than I'd like). I know my idle is a little higher than you recommended, but this is honestly been the sweet spot for me so far. Again, I'm sure there's something I'm missing but I still can't seem to put my finger on it at this point.

The first screen shot is in open loop on a cold start, and the second screen shot is from the same log just after about 25 minutes of log time.

[Dayhoff35]

i have mine sitting at a smooth 10 i switchd back to 93 though so i have to redo my file

[silverbullet08]

[QUOTE=Freakotec;299415]Wow man. What is going on with your maf in that log if you don't mind me asking? It's showing that you're flowing a TON of air at idle and at a crazy high frequency. Something going on there that I'm missing?[QUOTE]

That would bepart of my discovery..

[Dayhoff35]

i see what you did there lol, gonna mess with that tomorrow.

Started from scratch on my 93 tune since i had to switch back . This is what i got.

[projectlnf]

allright so i have noticed alot while fooling around with these tables.. i have noticed if i left my main spark alone and kept my DAL at where they have always been.. BUT i try and take my optimum spark tables UP it actually reduced my over all timing.. i went from 16 and 17 up at the top to 12 and 13 and i only took my optimum up 1 number at a time and it was only in a very few cels..

so therefore i have seen if you take DAL UP and optimum UP it will reduce your over all timing.. if im wrong please correct me because maybe im doing something wrong?

[cobaltssoverbooster]

ive seen both ways with mine: too much opt tq and it lowers and too little and it lowers but when i found the happier spots it follows as commanded.

just a thought but what if the opt tq refrence values are off too much, then it might reduce timing to be safe.
say its too low compared to commanded it will think it needs to be lower to make opt power so it reduces it to try and make it match more.
if its too high then it doesnt agree and compensates by adding boost and retarding ign as if it were entering a safe mode.
just a thought....

[projectlnf]

ive seen both ways with mine: too much opt tq and it lowers and too little and it lowers but when i found the happier spots it follows as commanded.

just a thought but what if the opt tq refrence values are off too much, then it might reduce timing to be safe.
say its too low compared to commanded it will think it needs to be lower to make opt power so it reduces it to try and make it match more.
if its too high then it doesnt agree and compensates by adding boost and retarding ign as if it were entering a safe mode.
just a thought....

only way to find this out is test it. ill do a comparison to the tune i have now and datalog and a major change on the opt torque and data log and post it up maybe tomm.

[projectlnf]

ok as the logs say one is raised one is lowered i saw a big difference when it was raised.. and i didnt raise them that much at all but it knocked like crazy! it even knocked when it was lowered.. not as bad.. one thing i see with all my logs is that if my wot timing goes below 16* or 17* it will knock.. but i have tried raising my main spark in those areas and it doenst seem to help me at all until i raise optimum spark... then it goes haywire it lowered it down to almost 9* and it knocked even more...

[LNFnewb]

Wow! That is A LOT of knock!

[projectlnf]

Wow! That is A LOT of knock!

yeah before i started adjusting i had very very very little i changed to those and bam KNOCK!!