First start up, New build 355

[steveo]

i should note you dont want to get into closed loop too early, as the readings from a recently cold started engine will be wrong and just end up messing your BLMs up (which isn't a really bad thing, but they'll take some time to correct themselves)

[terpngator]

coolant temperature (also influenced by intake temperature), time, and o2 preparedness (via voltage) thresholds all have to be met. since you're running this thing idling, warmup takes a long time. the knock test should be turned on. im not sure what the thresholds for it are, and i've never had a car fail it... but screw that, just test the knock sensor with a hammer, whack your motor with the logger running and see if it registers knock counts. the knock sensor wont actually retard timing under certain MAP values, or under a certain coolant temperature value, but the counts will still increase. those tables are fairly clear in the xdf, im sure you can figure 'em out.will look at the log when i get home, glad it's going better for you

Yeah, I reved it up a bit to get the 02's heated up, seemed to work. Still feels like it needs something, not sure what right now. When I rev it up, it jumps off of idle quick, like right now, no hesitation, or lag, at all. I'll try the hammer method for the knock test. I'm pretty good with hammer diags and repair.

I'm interested is your assessment of how the fueling/timing is doing at idle.

i should note you dont want to get into closed loop too early, as the readings from a recently cold started engine will be wrong and just end up messing your BLMs up (which isn't a really bad thing, but they'll take some time to correct themselves)

Got it!

[steveo]

at idle, timing is a 'by feel' thing. you want to advance it until you get a smooth idle (with minimum of unburned fuel) and no more. bigger cams seem to like quite a bit of idle timing. push it too far and it'll get misfires, and smell weird.

there's actually a way using mode 6 comms to jack up timing and test various idle speeds in tunerpro without flashing a new bin (then just make those changes in the bin so they stick). unfortunately it's not in the ADX yet.

i think ku4ro is workin' on it, i've never cared about fixing the tunerpro adx for this car.

[steveo]

finally saw your log;

now it's more typical of a build like yours. it still starts out running fairly rich and has to trim back, and does eventually hit a limit. there isn't much of a split between banks.

now you need to get it on the road and stop trying to tune this thing in your garage..

[terpngator]

finally saw your log;

now it's more typical of a build like yours. it still starts out running fairly rich and has to trim back, and does eventually hit a limit. there isn't much of a split between banks.

now you need to get it on the road and stop trying to tune this thing in your garage..

Thanks Steve, for all your help. I greatly appreciate it. The body is still at the paint shop, but should be back to me by end of month. Still have to assemble and get the bugs worked out. Glad to get a running engine before the body goes on the chassis.

[terpngator]

finally saw your log;

now it's more typical of a build like yours. it still starts out running fairly rich and has to trim back, and does eventually hit a limit. there isn't much of a split between banks.

now you need to get it on the road and stop trying to tune this thing in your garage..

STEVE, In an effort to better understand the tuning process, what items in my tune can I play with (safely) while it's sitting here? Also, can you explain the theory, and your thought process, when setting these tables in my tune? RE: 1.063 on cyl 1 means a richer mixture? 0.933?? is that richer by that multiple, or does that lean the mixture? Thanks

[steveo]

im going to pull an RTFM on you.

this is from my XDF notes explaining the parameter, which you'd see if you hover your mouse over the item in the list:

This table allows trimming of individual cylinder AFR calculations. It is a multiplier, increasing it richens the mixture. Obviously 1 means trim is disabled for that cyl.

Some people have had success using infared measurements to tune these values.

also from my writeup on fbodytech.com:

http://fbodytech.com/tuning.html#idle

and solomon's website:

This table alters how each cylinder is fine-tuned based off the calculated fueling needs for each bank. A number below one leans out the cylinder, and a number higher than 1 richens it up.

The ideal way to tune this table is to use an IR thermometer to measure temperature at each cylinder exit and to use the results to tune each cylinder's trim until the temp readings all closely match. It is best to start with all cylinders at 1.00, and first have the BLMs close to 128 from VE/MAF sensor table tuning.

Generally, the middle cylinders (3-6, especially 3-4) will require the least tuning, so use their temperatures as the baseline.

It has been shown through practice that a leaner fuel mixture increases combustion temperature, and therefore a richer mixture decreases temperature. You can use this logic in reverse: cylinders reading hotter than the middle ones should have their trims increased (ex. 1.01), and cooler cylinders should be lessened (ex. 0.99). Start with 0.01 increments until you see how much the temperature is affected.

However, if a cylinder is severely starved of fuel, the temperature can actually read much lower from lack of combustion. This can happen with the two front cylinders, so if there is a major difference between some, with one or more reading much lower (over a couple hundred degrees Fahrenheit), then you should consider adding fuel to those first.

Obviously, this method is best done at idle. But, there are two tables, one for idle and one for off-idle.

For off-idle, without a dyno, with the car in park you could set the throttle to about 20% (with a stick on the pedal, or someone else holding it down), and then measure; or, for tuning while the car is moving, install EGT sensors into each cylinder exit point on aftermarket headers, and either be able to log their readings or have someone in the car with you doing it.

Tuning this table can also solve BLM splits, where one side of the engine is either richer or leaner than the other side (i.e., 126 for the left, 110 for the right). Having such a condition will reduce power and MPG and could cause a dangerous lean condition for one side or cylinder depending on how bad the split is.

anyway that project is looking really slick so far!

i wouldn't actually play with your tune much more without some driving datalogs, with one exception, how much is it going to weigh? i may have gone a bit far in your timing advance for something heavier like that.

[terpngator]

Yeah, I have read most, if not all, of the parameter notes. Most make perfect sense, or I can piece it together looking at items that are referenced, but sometimes there are things that are confusing for me. What is Solomon's web site? I've read through fbodytech several times, but I never think about going back when I have questions, so thanks for that.

New, this car weighed right around 3,000 lbs. Not sure now, probably a little less due to updated (lighter) suspension components, and body mods.

EDIT: I FOUND SOLOMON'S SITE.

[steveo]

it's gonna fly.

solomon's tuning tips: http://www.lt1pcmtuning.com/tips/

[steveo]

i think just take it for a good driving datalog the first time its together, avoid full throttle. it'll run better than you think. then we'll have a chat and figure out how to tune the rest of it based on the log AND by how it feels to you.

i looked at your log again, your BLMS at idle are actually good enough as far as the split goes; it's just that your maf table is probably a bit off due to cam reversion at low rpm. i would leave the cyl. trims alone till the rest of the thing is tuned... might just get better on its own once the maf table is in better shape.

[terpngator]

Yea, I hadn't planned on messing with any of the tune till I'm more familiar with everything. I really can not wait till the knuckleheads in this club I belong to see, hear and feel this thing run. I'm catching major shit about using this engine. My last build (57 Chevy) I used a carbureted BBC 572. I want this build, particularly the engine, to be a jaw dropper. Having a problem right now finding an accessory drive setup for the LT.

Some pics of my 57: Everything, except paint and interior upholstery, done by me. Hand built DOM chrome moly tube chassis, full, padded and leather covered roll bar, hand formed aluminum dash. 3 year build.

[steveo]

wow that's beautiful!