nAst1: Progress and Concepts Thread

[pocket-rocket]

Thats pretty sweet. I like the price point of it, but with being new to tuning the hit tracing helps me see where the ECM is reading and makes the ostrich worth it for me.

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[robertisaar]

not much of an "update", but i have been eyeing this....

http://www.moates.net/nvsram-module-kit-p-130.html

from what i understand and have read so far, the normal mode 4 command response was modified so that now mode 4 commands basically are bytes that are written to the NVRAM module. the module is mapped from $2000-$2FFF, which is convenient considering that the 9396 SRAM area ends at $1FFF. probably not a coincidence either.

with the patching MCS did to his BINs, he came out with this:

1 byte write $FF starting at $2000: F4-5A-04-01-20-00-FF-8E
2 byte write $BE $EF starting at $2000: F4-5B-04-02-20-00-BE-EF-DE

up to 8 bytes can be written at one time. seems simple enough. and from a quote:

I have working DOS utilities that can be used to upload and download bins to and from the ECM via ALDL. An upload takes about 25 seconds, and a complete download of the bin takes about 50.

so from the sounds of it, it ALMOST allows emulation...... just not emulation of the entire PROM, just 4KB of it. for $45, it probably isn't a bad option, and from what i understand a windows GUI was released as well, but........

is it worth the time to understand and support it? the patch he made for $8D seems REALLY, REALLY simple and would probably take no time at all to impliment and probably still retain normal mode 4 commands, but 4KB.... that's 14 17X17 tables.... or any random combination of stuff so long as it takes up 4096 bytes or less.



and here's the biggest thing: IF they were to be used, 7730 and 7727 could be used as well instead of only the 9396, BUT it would absolutely require everyone running nAst1 versions that use the extra RAM to use one of these modules, whether they're "emulating" or not... and the NVSRAM module seems to have it's own battery in it, which is supposed to last 10 years.... i have to wonder what would happen after the 10 years are up. would it still work like normal RAM and just lose it's battery-backed capability? will it outright fail? will there still be replacement NVSRAM modules that can be plugged in 10 years from now? 20 years? and does it interfere with the 9396's existing 2KB added RAM?

all of these are questions that make me want to stay away from it. of course, i could probably ask MCS and get most of these answers, but i'd rather not bother him if i don't need to.

do i need to?

[robertisaar]

revving up and down is the ECM trying to control idle speed. your IAC counts and spark advance are probably swinging at the same rate if i had to guess, since both spark and IAC are modified to control idle speed. there is too much correction happening too fast, so the engine speed is overshooting the target. to tone this down, you would need to change the idle spark correction to be less aggressive, change the IAC PID tables to be less agressive, or make it harder to get into the conditions that will allow engine speed to attempt to match target idle speed when moving.

quite a few options there. and hard to tell which will work best for your application too. even GM seemed to have issues with this.

i really don't know why BLM isn't updating then... as long as INT is far enough away from 128 for a sufficient amount of time, then BLM is supposed to move. for some reason, it's getting reset to 128 constantly, and only at idle from the sounds of it... i wonder if it's BLM cell 0 related then.

[caffeine]

Ok I gave that a shot, it didn't change the BLM not updating and once in a while I also now stall while idling. I also have this issue where when I'm coasting in neutral down a hill the engine will rev itself up and down constantly until I either put it in gear or come to a stop (only does this sometimes, happens more often at higher speeds). I'm assuming this is IAC related?

[caffeine]

Thanks I'll try that tonight

[robertisaar]

interesting.

i notice when you're at an idle, you're REALLY close to being at the BPW limit to allow BLM updates at idle, and a lot of the times, you go under it.

do a search for these and cut them in half(EDIT: maybe even a little more than half, since you idle near .6mSec when fully warmed):

Low BPW Threshold Required to BLM Learn in Idle Cell (KLCBPWIL)
High BPW Threshold Required to BLM Learn in Idle Cell (KLCBPWIH)
Low BPW Threshold Required to BLM Learn in non-Idle Cell (KLCBPWL)
High BPW Threshold Required to BLM Learn in non-Idle Cell (KLCBPWH)

otherwise, when you're in the correct conditions to allow BLM updates, it looks like they happen, when necessary.

[caffeine]

post/send an XDL and current BIN, i want to see what's causing issues here.

LX9 highway cruise enabled.bin LX9 logs.zip
Here is my latest .bin and a couple logs. I think the one labelled "crap idle" is the one where I temporarily enabled the idle VE table.

[robertisaar]

post/send an XDL and current BIN, i want to see what's causing issues here.

[caffeine]

cell 0 is idle cell, what kind of thermostat are you running, since there is a BLM enable coolant temp qualifier.

the 1.05 bins (they are the latest i've released, BTW) should have single-fire disable completely already, so i'm not sure what you did to "disable" it other than possibly making the qualifications to get into it even more difficult/impossible to get into.

there is a flag for TCC lock to enable highway spark called "TCC Lock Required for Highway Spark Advance" disable that, if it isn't already.

the temporary lack of rev-down in DFCO is usually caused by IAC logic. next time you look at a log that has it happening, you'll likely see that the IAC quits moving downward for a short amount of time before continuing to drop. there are settings to mess with this to match it to your liking, but i can't remember what they are off-hand.

Ok I'll check the iac stuff next. I did manage to get highway cruising working. Turns out I had converter over temp spark disabled by maxing out the min coolant temp to enable.

As for the idle BLM being locked at 128, I am running the stock 195* thermostat and a heated O2 sensor. I tried enabling the idle VE tables and found I could no longer rev up my engine after idling when warm so I disabled it again. Enabling the idle VE table made no difference as to the 128 BLM.

Another question: I can't seem to get my low MAP VE cells to get any leaner than 122 or so. Is it possible that my injectors are already squirting as little fuel as possible since I'm running the stock 24# injectors at a constant 55 psi (vette fuel filter/regulator)?

[robertisaar]

You should add a permanent link in your signature for the latest file downloads..

I may actually make the switch this year since I'm not entirely happy with the Holley 950.

EXCELLENT idea. i'll just link to the post that i have release notes/ZIP in. i have a hard time finding the files myself and i upload the damn things

EDIT: done. now i'll just have to remember to update the link when i post updates.

speaking of: working out a few bugs on my bench, when i have that done, the first revision of the 3BAR code will be posted assuming it is 100% functional. for this version, boost fueling will be done only through the above 100kPa fuel multiplier table and boost spark will be done only through the boost spark retard table. this is only due to me trying to get this out as soon as possible, since my last release was in october. i don't think it will take long to get the next version out, the one that will convert the 3 total VE and 3 total main spark tables into 4 total VE and 4 total main spark tables, 2 each for N/A and 2 each for boost. at that time the boost BPW multiplier will still be present and adjustable for rough fueling correction, but the boost spark retard table will be removed since it will be unnecessary.

[Superdave]

You should add a permanent link in your signature for the latest file downloads..

I may actually make the switch this year since I'm not entirely happy with the Holley 950.

[robertisaar]

cell 0 is idle cell, what kind of thermostat are you running, since there is a BLM enable coolant temp qualifier.

the 1.05 bins (they are the latest i've released, BTW) should have single-fire disable completely already, so i'm not sure what you did to "disable" it other than possibly making the qualifications to get into it even more difficult/impossible to get into.

there is a flag for TCC lock to enable highway spark called "TCC Lock Required for Highway Spark Advance" disable that, if it isn't already.

the temporary lack of rev-down in DFCO is usually caused by IAC logic. next time you look at a log that has it happening, you'll likely see that the IAC quits moving downward for a short amount of time before continuing to drop. there are settings to mess with this to match it to your liking, but i can't remember what they are off-hand.

[caffeine]

for idle, make sure that the idle VE table is enabled, by default i have it disabled in all factory BINs, but one flag change and it will be used when in the conditions that are adjustable for you to consider "idle".

BLM at 128 is either the BLM being purposely locked to 128 in the tune or you haven't gotten warm enough to allow the BLM to start moving.

Ok I didn't know that the idle VE needed to be enabled. It actually idles fine since I disabled single-fire altogether; with single-fire enabled it would randomly stall while idling. BLM always is at 128 when idling regardless of whether closed-loop is enabled or not. It is in cell 0 also if this matters. I don't know how it would be locked to 128 allways in the tune as to my knowlege I haven't changed anything that would cause that.

lean cruise REQUIRES highway spark to be active, so if you've zero'd out that table or don't allow it to be activated, lean cruise is disabled as well. initially highway spark was called "cat overtemp spark" since that's what GM referred to it as, but sometimes they mislead like that. also, you would obviously need an accurate VSS signal as well and be above the MPH thresholds. and since you're a manual, make sure the requirement for TCC lock is disabled for highway spark.

Ok I had no idea about highway spark tables, I simply enabled the lean cruising flag and adjusted the scalars for speed. Where will I find the requirement for TCC lock?

when switching between tables, no fuel or spark changes beyond the normal main spark and VE calc are effected. when in DFCO, VE and spark changes will not be felt, since the engine is not in any way producing power.

also, be sure you are indeed running off the newest base BINs, since there were a few bugs i fixed that it seems you might be encountering.

Ok I just thought it was weird that while decelerating it will stop revving down for a half a second or so before continuing on. I thought that switching tables would be the most logical explanation but I must be wrong. It's also difficult to tell exactly what RPMs it happens at since my tach is way off in my dash (was with the stock engine as well).

Oh and I'm running version 1.05. Is that the latest version?

Thanks for your hard work producing this code BTW. Tuning has so far been going quite well I think.

[robertisaar]

for idle, make sure that the idle VE table is enabled, by default i have it disabled in all factory BINs, but one flag change and it will be used when in the conditions that are adjustable for you to consider "idle".

BLM at 128 is either the BLM being purposely locked to 128 in the tune or you haven't gotten warm enough to allow the BLM to start moving.

lean cruise REQUIRES highway spark to be active, so if you've zero'd out that table or don't allow it to be activated, lean cruise is disabled as well. initially highway spark was called "cat overtemp spark" since that's what GM referred to it as, but sometimes they mislead like that. also, you would obviously need an accurate VSS signal as well and be above the MPH thresholds. and since you're a manual, make sure the requirement for TCC lock is disabled for highway spark.

when switching between tables, no fuel or spark changes beyond the normal main spark and VE calc are effected. when in DFCO, VE and spark changes will not be felt, since the engine is not in any way producing power.

also, be sure you are indeed running off the newest base BINs, since there were a few bugs i fixed that it seems you might be encountering.

[caffeine]

Don't know if this is where I should post this but I'm currently running a 3500 swap in a 4 speed manual Fiero on nAst1, and I'm just having a few issues. First, how do I tune the idle table? I seem to be running rich no matter how much I decrease the values in the idle table but when I'm logging the BLM is constantly at 128 but the INT stays around 95-105. Another thing I can't seem to figure out is lean cruising. When I'm cruising on the highway it still always says 14.7:1 is the target AFR. Not sure if it matters but at highway speed I'm revving at between 2400 and 2600 rpm. I have the lean cruise set to be enabled around 80 km/h at IIRC 15.6:1. Oh and one more thing. When in DFCO, I can seem to feel it when the computer switches tables; like it leaves DFCO for a second and re-enters it as it moves from the 5200 table to below (and also when it moves from the 2000>5200 to < 2000).