tuning assitance, 15gs, 550s, chrome ecu

[napkinthief]

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

[TurboSinceBirth]

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?

[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.

[napkinthief]

^++ 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.

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...

[napkinthief]

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.

[Toni]

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?

[Greg E]

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

Is your fuel table still stock?

[napkinthief]

Is your fuel table still stock?

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.

[napkinthief]

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.

[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.