tuning assitance, 15gs, 550s, chrome ecu

so im just not getting it...

i have boost set to 14psi max, via truboost. i ahve all support mods for 15gs, 550c inj, a1000 fpr @ 42psi, downpipe, precat eliminators, wideband.

car runs pig rich 10.2 or less during WOT after 4k rpms. before 4k tho, it sounds like a monster accelerates hard as well with nice afr ranging 11.0-12.5

i put in both o2 sensors, at a horrible attempt to get fuel trims working. they are pinned at 0 across all 4 lo and mid.

i tried to modify some tables following the ecuflash tune guide (was like 16 videos on youtube) but the car would stumble and sound like crap, i reflashed the oem map again. the only mods i have edited now are injector, injector volt latencies, and disabled a bunch of peripheries to eliminate CEL. i also have launch control enabled at 4k rpms, and it sounds OK, but doesnt bounce off the limiter quick enough? (compared to an old MSD setup i had on a dsm)


id really appreciate if soemone can send me a map of a car with similar mods, so I can see what exactly is different between the maps...or if someone can help me via remote tune, to get me in the general vicinity of where i need to be. as of right now, the car WOT feels slower than 9bs at bpu

You need to figure out why your fuel trims are not cycling. They shouldn't be zero. You may have a wiring issue. Do you have Brett's or Adam's ecu?

^++ I concur.

Get your fuel trims to cycle and stablize, short terms should ALWAYS be moving, long terms can be at zero if you have it perfect, but that is rarely the case. Then adjust your VE at higher load cells to get it back in-line/within your target AFR.

Post up your global fuel settings and injector ms to ensure it is correct.

I am assuming; no vacuum leaks or maf issues; that your VE table needs to be adjusted at 1400 and 1600hz values.

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Originally Posted by niterydr

^++ I concur.

Get your fuel trims to cycle and stablize, short terms should ALWAYS be moving, long terms can be at zero if you have it perfect, but that is rarely the case. Then adjust your VE at higher load cells to get it back in-line/within your target AFR.

Post up your global fuel settings and injector ms to ensure it is correct.

I am assuming; no vacuum leaks or maf issues; that your VE table needs to be adjusted at 1400 and 1600hz values.

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i dont know whom i got the ecu from, its been at least 8 months. i think it was adam though.. is there a difference?

my narrowband o2s are cycling at idle...the LTFT is not changing. I let the car idle for about an hour with short drives inbetween (less than a mile) just to get the fluids flowing. i then took her on a highway drive for ~35 miles each way, crusing in 4th and 5th between 2-4k rpms, this should have allowed the trims to reset twice at least..


i am going to try to adjust the high end of the VE table tonight....that sounds most reasonable why its too rich...



what wiring issue would cause LTFT not to adjust? only things i have wired in are the flash adapter...im assuming my harness is good since i am getting reading and voltage from both o2 sensors.. i was thinking it may be evoscan, but i looked around and the request codes match other peoples...

done some more reading, heres a short excerpt from Greg E's tuning post:

"It's just like an SAFC only instead of adding or taking away fuel based on RPM, you're going right off the MAF signals itself. If you're feeling crafty, you can even disable closed loop entirely and tune strictly off your wideband and this table alone. Log your wideband and 2 byte airflow and add or take away fuel from this table in the HZ range till you get your desired AFR. The next version of chrome will have this table extended AND allow for finer correction values (.1% instead of 1%) so you can really get particular with fine tuning your car. Use the fuel table itself as a target AFR table."

So theoretically, I can disable closed loop, tune for open loop and make drag passes safely? The biggest negative being I will have some horrible gas mileage? Enlighten me if I am missing something.

This sounds suspiciously similar to mine. I can't get my trims out of 0 but my afrs cycle around 14.7 and my NB o2s cycle nicely. Almost as if, it's working but not reading correctly. I flashed some older roms I had and I could get it to work but couldn't pin point it even moving things to stock one by one.

Do you have two widebands or just one? If two(or one on one bank), do they cycle around 14.7? What do your narrow bands cycle between?

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Originally Posted by napkinthief

car runs pig rich 10.2 or less during WOT after 4k rpms. before 4k tho, it sounds like a monster accelerates hard as well with nice afr ranging 11.0-12.5

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Is your fuel table still stock?

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Originally Posted by Greg E

Is your fuel table still stock?

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as of right now it is, i reflashed back to the 238xxxxx.bin file i got with the chrome ecu

only modified areas are injector size (525) and latency table (got it off another user on this forum)

also disabled some periphery to turn off CEL. everything else is stock.

let me add i tried to shift a section the fuel map to the right, but the car stumbled under boost pretty bad, and unsure what i did wrong i just reflashed back to stock to avoid messing anything up.

I'm confused... You're running 525 cc injectors?

In that same post you quoted about tuning with the VE tables, I talked about using the fuel map as a target AFR map and then using the VE table fine tune the AFRs to that target. If you left the map at 10.2, 10.1 like stock, what's why you're seeing those fat AFRs under boost.

If you get too far into the 9s for AFRs you'll foul the plugs and that will cause stumbling.

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Originally Posted by Greg E

I'm confused... You're running 525 cc injectors?

In that same post you quoted about tuning with the VE tables, I talked about using the fuel map as a target AFR map and then using the VE table fine tune the AFRs to that target. If you left the map at 10.2, 10.1 like stock, what's why you're seeing those fat AFRs under boost.

If you get too far into the 9s for AFRs you'll foul the plugs and that will cause stumbling.

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they are PTE 550 injectors, they came with a flow card showing 440cc @ 36psi and 528cc @ 42psi. my regulator is a touch over 42 at idle, so i set it close as possible.

i am going to give it another shot tonight, its pretty humid/foggy out, but what the hey.

ill post results here...

Fuel pressure is relative to manifold pressure. From a code stand point using 525 for the injector scaling will make your motor run richer than using the 550 number. This is completely separate from fuel pressure. Your sensors are telling you that you have too much fuel so you should stick with the 550 number, lean out the rich areas of the fuel table and go from there.

Ok ill bump it back up to 550 and see the changes...

as for latency, im using

4.69 = 3.825
10.99 = 0.810
12.01 = 0.675
12.96 = 0.585
13.99 = 0.510
15.01 = 0.405
18.68 = 0.300

the first and last voltages are stock, and the latency value is stock...the inbetween is adjusted.

also looking at timing, is there a reason its @ 10 across the board at 4k rpms above 140 load?, am i safe to slowly bring it up until i see knock or is it a wasted effort?

still not getting LTFT to log...not sure if its just not logging or its not working.

1. Low and Mid trims should be tuned at idle using the VE tables. Probably need to pull 10% below 100 Hz
2. Closed loop is not in effect at WOT. It's only used at idle and cruise.
3. 10.2 AFR at WOT is the stock target. You can change it via the big fuel map
4. If you want to lean out WOT you can pull fuel at 1600 Hz in the VE table (coarse adjustment) or increase the AFR targets in the big fuel map at the higher loads and rpms
5. Make sure you log 2 byte load and 2 byte air flow. The single byte readings cap out too low for upgraded turbos

If you are not running stock injectors then tune the injector maps to dial in the trims. The only way is tune ve for that is if I was on 360s and the trims were off, otherwise you are chasing the wrong thing and if you change injectors later you have to start all over.

Sent from my RM-845_nam_vzw_100 using Tapatalk

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Originally Posted by Forest Gump

If you are not running stock injectors then tune the injector maps to dial in the trims. The only way is tune ve for that is if I was on 360s and the trims were off, otherwise you are chasing the wrong thing and if you change injectors later you have to start all over.

Sent from my RM-845_nam_vzw_100 using Tapatalk

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Huh???

Chris, JFast hacked your account and is making off the wall posts with it. :p

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Originally Posted by Greg E

Huh???

Chris, JFast hacked your account and is making off the wall posts with it. :p

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no, I just think you shouldn't tune the airflow maps if your injector latencies and scaling are wrong.

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Originally Posted by Forest Gump

no, I just think you shouldn't tune the airflow maps if your injector latencies and scaling are wrong.

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Oh I see now. Yes, true. :)

Order of operations:
*Set injector scaling and latencies
*Set fuel table
*Fine tune with VE table

sorry, when I post from phone it doesn't always make sense, lol. I'm kinda on the edge of the texting generation :)

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Originally Posted by Greg E

Oh I see now. Yes, true. :)

Order of operations:
*Set injector scaling and latencies
*Set fuel table
*Fine tune with VE table

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I got it, but have experienced it very personally! :p

so just my update

fuel trims are not logging, no way, no how, tried differnt o2 sensors, maybe something is hard wired incorrectly...

at idle, the nbo2s are cycling, the wideband is showing 14.5-14.8 afrs at idle/cruise


i tried playing with the values at 1600mhz lowering the ve, i went down 1 point at a time until reaching 101, (started at 106). at 101, the afrs stopped dropping at 11.0. i also had to smooth the effect from the previous 3 cells to keep it from dipping below 11 before staying there. the car was still flooding as it bogged heavy and misfired a bit after shifting.


ive reset everything again, bumped the boost back down to WG pressure. it runs great, at 7psi...

i think i need to get my fuel trims working...before i start boosting more.

in in nj, a few minutes out of NYC....any recommendations id like to go somewhere to get tuned.

As said before the fuel trims aren't used at WOT. That is the open loop region. If you want to lean it at WOT then you lower the VE at 1600 Hz like you're doing. You probably shouldn't go much above 11 AFR though if you're on gas.

As far as closed loop goes, just run the car in your driveway and log the O2 sensors and the low trims. The low trims should adjust once every 4 minutes. Check that your O2 sensors are cycling.

If the low trims peg at +12.5 then you need to lower VE below 100 Hz. If they peg at -12.5 then you need to raise VE below 100 Hz. Don't bother looking at the trims at WOT.

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Originally Posted by Jimvr4

As said before the fuel trims aren't used at WOT. That is the open loop region. If you want to lean it at WOT then you lower the VE at 1600 Hz like you're doing. You probably shouldn't go much above 11 AFR though if you're on gas.

As far as closed loop goes, just run the car in your driveway and log the O2 sensors and the low trims. The low trims should adjust once every 4 minutes. Check that your O2 sensors are cycling.

If the low trims peg at +12.5 then you need to lower VE below 100 Hz. If they peg at -12.5 then you need to raise VE below 100 Hz. Don't bother looking at the trims at WOT.

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the trims are 0, they dont update.

i was able to adjust afr by lowering the ve at 1600. sweet spot was at 101, do you smooth out the slightly lower points? at 1400 and 1200?

Are you using the 3000GT EFI XML that was provided with the Chrome V2 software? Screen shot of Evoscan logging your car?

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Originally Posted by Jimvr4

Are you using the 3000GT EFI XML that was provided with the Chrome V2 software? Screen shot of Evoscan logging your car?

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Yes i am, i can get a ss later. everything else is logging, 2 byte load and airflow...the request values are correct...

How long have you let it idle, or drove below 30% throttle?

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Originally Posted by CoopKill

How long have you let it idle, or drove below 30% throttle?

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In an attempt to let it start trimming, I let it idle for about an hour. I moved it around the parking lot maybe 3 times in that hour, definetly under 50% throttle. Afterwards I took a 35 mile cruise in 5th @ about 2-2.5k rpms aswell.

I am going to go in on the wiring with my multimeter this weekend. Theres gotta be something up. Also going to format a miniSD and try to log from the tactrix directly. Hope for some results.


Correct me if I am wrong tho, but if I want to make some 1/4 mile passes, I only really need to tune for WOT? since open loop the trims wouldnt be used anyway. Getting the trims logging and set correctly is just going to improve gas mileage and drivability? Car drives great in closed loop at the moment, no knock up to 14psi (havent has the urge to go further yet lol), feels and sounds amazing...

I wanna add, the more I am driving it slowly, and letting it just idle, the better the gas mileage I am getting. First tank yielded about 120 miles, running rich. 2nd tank is about 150. now third im at 150 miles and still a 1/4 left. maybe its just since im staying out of high boost tho

Yes, It runs in closed loop at idle and cruising at vacuum. When you go into boost it goes into open loop pretty quickly. Good fuel economy depends on keeping out of boost.

If you want to make some 1/4 mile passes just make sure you tune well for WOT.

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Originally Posted by Jimvr4

Yes, It runs in closed loop at idle and cruising at vacuum. When you go into boost it goes into open loop pretty quickly. Good fuel economy depends on keeping out of boost.

If you want to make some 1/4 mile passes just make sure you tune well for WOT.

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ok thats my goal, going to island raceway sunday i believe.

i should be able to really open her up there and get some nice logs.

ill post results ...

am i safe to say with my build i should hit 13.5? without 1.6s 60fts.. lol

I wouldn't be doing WOT pulls if my logs weren't showing proper data...IMO...especially if your car is stuttering, bogging, backfiring, etc...

When I initially got my adapter harness...the o2 wires were switched...that was the reason why my trims were stuck...

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Originally Posted by napkinthief

ok thats my goal, going to island raceway sunday i believe.

i should be able to really open her up there and get some nice logs.

ill post results ...

am i safe to say with my build i should hit 13.5? without 1.6s 60fts.. lol

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thats tec 15gs, 550cc inj, some weight reduced, 515ft/lb clutch, embc (truboost), downpipe, no cats

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Originally Posted by NOMIEZVR4

I wouldn't be doing WOT pulls if my logs weren't showing proper data...IMO...especially if your car is stuttering, bogging, backfiring, etc...

When I initially got my adapter harness...the o2 wires were switched...that was the reason why my trims were stuck...

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ya thats my point, im going to try to get rid of the sputter/bog at high rpm, anything closed loop the car sounds and feels great.. in closed loop, ive already roasted srt4 from a roll, but when i hit on WOT its flooding im pretty sure. trying to tune taht part down.

If you are doing any kind of racing, esp roasting someone you are not in closed loop, at least you shouldn't be :)

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Originally Posted by Toni

If you are doing any kind of racing, esp roasting someone you are not in closed loop, at least you shouldn't be :)

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are you insisting its possible im never getting to closed loop?

He's saying our cars don't make power while in vacuum (closed loop). All the power is made in boost. If you have problems in WOT then you need to look for boost leaks. These cars run rich in boost by design. If they didn't then everyone would be blowing up motors due to detonation.

So i pressure tested, had a leak at the iac motor. the rear bolt that holds it in was missing.

i also regapped all the plugs to .042, checked the PTU, coils, wires.

it stopped bogging and flooding at high rpm...

i kind of want to re-flash the previous tune to see if it was just the iac leak, or the combination of both..

car is pulling very hard at 12 psi, but its very non-linear. feels like idle-2500 is a normal v6 (expected), 2500-4000 is almost like clutch is starting to slip, but at around 4200 it grabs hard all the way to redline. arent 15g supposed to spool faster? with the minor changes in the ve table (i think i took 2 away in 1400-1600 and 1 in 1200), im seeing afrs no lower than 10.9 and no higher than 11.5 in WOT. no knocks on 93 octane.

.42!!!

What plugs? Mine ngk r56-11a coppers are gapped at .25

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Originally Posted by NOMIEZVR4

.42!!!

What plugs? Mine ngk r56-11a coppers are gapped at .25

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autolite copper from local autozone. was cheapest copper plugs like 2.30 ea

i change them often tho