pulling timing not in program

[496chevy]

Hi guys i'm knew to efi live forum. i've got a 2001 4x4 p/u truck with a custom operating sys. 2 bar in it and have been working with it for a couple
of month now when i'm not at work. It's been alot of work starting from scratch. the truck was a 496 allison to begin with and has evolved into a twin turbo 604 cu truck. my problem is that something in the programming is pulling 4-6 deg of timing that is not on any of the timing maps that i can tell.
right now i have zeroed out all the timing maps for everything, the only timing maps i'm using are the high and low octain maps (which are the same) and the optomal timing map and the boost retard map. i log the truck and it seams that at wot it is pulling 4-6 degrees from somewhere. it's a drive by wire throttle and i'v increased the maps for them to not set a 1514 code. All the torque management is zeroed out and it has no traction control. i'm wondering if increasing the expected torque maps has some effect on the end timing tables? any input would be appreciated. thanks

[joeygc5]

Is it pulling the timing once you go WOT and maintaining through the pull? Or does it start later on, maybe during a shift region/time?

[joecar]

Can you post log and tune files.

[496chevy]

it pulls timing after the shift.i will attach the program and log file.

[nevinsb]

It looked like the torque reduction was properly disabled, but watching the log, I am seeing values for KR (Knock retard). Is this where you are seeing the timing lost?

[496chevy]

looks like you're right. is it just me or does it not look like i should be running alot more timing? i mean with the older engines i've worked on at 2.5 psi of boost i should be at about 28 degrees not 15. my afr are about 10.8 to 1 at wot. any thoughts?

[nevinsb]

There's a lot of things that could cause it like distributor incorrectly set, noisy valvetrain, exhaust hitting the frame. I'll try to take a look at it when I get home, but it will be very tough to troubleshoot without wideband in the log files.

Do you have any information like whether it is intercooled, compression ratio, or other engine modifications?

[496chevy]

some more info on my truck. the engine is a 572 cu bored .030" and stroked to 604 cu. it has raylar alumium heads cnc ported and polished. the engine was built for me by Raylar engines and i had them lower the compression ratio to 9.0 to 1. they custom ground the cam the same as their na racing engine but added more exhaust duration for the turbos. i have an intercooler and water/methanol injection. 72lbs/hr injectors at 62psi
(about 82lbs/hr). the turbos are sx400 each will move enough air to suport about 700 hp. i do have an LM-01 but it won't recognize the serial port in it so i can't log with it until i get it fixed but the display on it says the afr is about 11.0 to 10.6 at wot. i also have a pyro on each bank which has helped with the tuning and i have an autometre narrow band o2 sensor for tuning cruse areas of the VE table. i can't find much info on tuning with egt's but i try to keep them under 1350 deg f at low load. wot the egt's will go to 1600 deg. on the exhaust side i have headers going into 3" than both 3" into 4" to the remote mounted turbos. duel 4" leaves the turbos. intake is duel 5" to the turbos and than into 3.5" to the 3" intercooler and into 3" to the 3" throttle body. i have built all of the truck myself and can't remember all the mods along the way but still plan to upgrade the intercooler to 3.5" and put a larger throttle body onto it. the fuel system is a 3/4" from the fuel tank to a weldon fuel pump to 1/2" to a custom fuel rail with weldon regulator. i'm shooting for a 1000hp on premium with good driveablity. i have only run 3 psi of boost and am taking the tuning slow. i've got a reasonable idle at 750 rpm and tuned to 3psi but still working on the ve table and timing maps to get them better but just haven't had enough time to work on it lately. the ignition is msd coils one per cylinder the same as the ls-1. the engine is brand new and just broken in and put synthetic oil in it for the first time. i relocated the intake air temp sensor to the 3" down stream of the intercooler. i've been working on this truck for 7 years but have had efi live for only a couple of months. the ability of the programming is great but a little overwelming at times with so many variables and it's hard not to make more than 1 change at a time. thanks for any help.

[Dynotuner]

Hey 496, I'm not an EFI expert either, but am working on a similar setup (HP numbers) for a friend. It looks like the PCM has used the 'engine protection mode' timing {B5921} and then reduced it by the KR number and finally reduced it further by the boost reduction table. Just a quick glance - I'll look further. In my case, I'm learning the software on a cammed LS1 engine with a supercharger that is intended for the 7 liter, fully built engine that will replace it so even though I'm flirting with disaster and over 20deg of timing at 5psi, I still have not triggered knock. I'm wondering if you're getting false knock too. The last thing to consider is the 'burst knock' parameters {B6212} - despite it's name, it just pulls timing based on airflow change programmed in {B6210}. That one has gotten me before.

Again, I'm learning too and had a minute to look over your logs with my Sunday morning coffee. Hope some of this leads to solution for you.

[496chevy]

i looked at b6210 and it could be pulling the timing. do i need burst knock or should i zero the burst knock retard table? or maybe increase the burst knock delta air mass table? as for the b5921 my operating sys doesn't seem to have it. i used the stock 496 truck tables as a starting point so i haven't changed these tables yet. thanks for the info.

[Dynotuner]

Again, no expert here, but I would expect your engine to have some serious dynamic airflow changes when the throttle goes wide - and maybe on shift too. I was dyslexic when I typed {B5921} - that should have read {B5912} ;-)

If it were mine, I'd increase the burst knock delta or even disable temporarily and then find a way to determine if the PCM is trying to use the {B5912} to see if you can get to commanded timing.

You may want to smooth out the high oct. spark table too - I imagine it's that way because you're trying to solve this issue, but you may probably want to fit a spark curve to that to inversely follow the torque peak. If you're revving past 5600 rpm, your EGTs will likely go up quickly as the timing heads toward 10deg minus the boost table timing.

Hope this helps. I'm right behind you in getting to that problem. I hope to be finished wrestling with large injectors, idle quality, and low speed driveability on the dyno tomorrow. If I have time, I'll do some timing changes and give you real world feedback.

[496chevy]

i zeroed out the burst knock and pulled 3 degrees form the high and low oct. maps. the power is much better and the timing is less erratick. i will post my newer logs and program. i did log the lm-01 but afr aren't the actual # but still help to smooth the ve table. it looks like i could use some more timing. thanks for the good info.

[nevinsb]

Oh, no problem. I actually haven't even gotten a chance to look at the tune yet since I destroyed one of the rear rotors on Friday and have been running around on the motorcycle in the snow trying to find parts to repair it.

The reason I was asking about the mods is because some of the cams with the long duration at high lift are very noisy and can actually give you false readings on the knock sensors at high RPMs.

[Dynotuner]

That looks better - at least the logged timing = high octane spark + KR. I agree that you probably need more timing - the boost retard table {A0010} will pull timing as needed for boost.

Closer look at cal and logs makes it really look like false knock triggering. Look at {B6244} (looks like weird random artifact in the table - unless there is something I have to learn about engines knocking arouns 800RPM under very light load) and {B6250} although based on the parameter description, {B6255} will win out since it has a higher value everywhere. {B6245} appears to be adding sensitivity at 4k also.