LS1FREEK
June 19th, 2017, 02:09 PM
Guys this has been killing me, literally... So I'm gonna do my best to try to explain whats going on here.
I'm working on my brothers 1971 Nova, LQ4/4L80e/Turbo swap. 2000 Z28 harness and ECM. 02020005 Custom OS (based it off of a 12212156 2002 Z28 file).
On his first build we had some what we believed to be Siemens Deka 60# injectors, thats where it all started SMH... I got inj data from FIC for those, typed it all up in the tune, but right off the bat, tune seemed rich everywhere in light throttle areas and lean in heavy throttle areas, as if the injectors weren't very linear. Called FIC, they were maybe assuming i didn't know much about tuning, after i explained i had been successfully tuning cars for over 9 yrs he started to think the injectors might be ebay knock offs. We sold those and bought some new 95# FIC's.
Well after installing the new FIC 1000cc Bosch injectors, I started from scratch with a new tune WITH FIC injector data just how I've normally done successfully with all my builds. Started the car and immediately noticed it was rich at idle and light throttle just sitting there, so started taking fuel out of the VE table, but it made no difference, i even tried drastic numbers like -200%, no difference. I sized the injectors bigger in the tune and that did the trick. Finally got the STFT close to 0% at idle and very light throttle, but then any moderate throttle it would go extremely lean, even with the VE at like over 120% at 12psi map and it was still lean.
I moved the injector flow rate back to where they were supposed to be and noticed that the minimum pulse width the PCM would ever command was around 2.319ms. So at idle and and light throttles it would never command less than 2.319ms, EVEN if i commanded leaner AFR in the DVT section of the scantool.
DATALOG ATTACHED
So here's whats weird, IF i turn fuel trims on, it'll pull fuel and idle/cruise 14.6 AFR... some times itll pull upto -70%, the problem with that is then when you tip into the throttle it will hesitate and go lean for a sec before it recovers.
SOOOOO FRUSTRATING!!!!!
Ive been tuning Gen3 LS' stuff for over 10 years, never had this problem before. In fact, Ive tuned multiple trucks also with FIC 95's and never had this problem. I figured there must be an underlying issue, but today I was tuning another car with nearly the same setup (except 5.3 and truck harness) and it is doing the exact same thing to me...
MY BROTHERS TUNE AND A DATA LOG IS ATTACHED
21224
21225
I'm working on my brothers 1971 Nova, LQ4/4L80e/Turbo swap. 2000 Z28 harness and ECM. 02020005 Custom OS (based it off of a 12212156 2002 Z28 file).
On his first build we had some what we believed to be Siemens Deka 60# injectors, thats where it all started SMH... I got inj data from FIC for those, typed it all up in the tune, but right off the bat, tune seemed rich everywhere in light throttle areas and lean in heavy throttle areas, as if the injectors weren't very linear. Called FIC, they were maybe assuming i didn't know much about tuning, after i explained i had been successfully tuning cars for over 9 yrs he started to think the injectors might be ebay knock offs. We sold those and bought some new 95# FIC's.
Well after installing the new FIC 1000cc Bosch injectors, I started from scratch with a new tune WITH FIC injector data just how I've normally done successfully with all my builds. Started the car and immediately noticed it was rich at idle and light throttle just sitting there, so started taking fuel out of the VE table, but it made no difference, i even tried drastic numbers like -200%, no difference. I sized the injectors bigger in the tune and that did the trick. Finally got the STFT close to 0% at idle and very light throttle, but then any moderate throttle it would go extremely lean, even with the VE at like over 120% at 12psi map and it was still lean.
I moved the injector flow rate back to where they were supposed to be and noticed that the minimum pulse width the PCM would ever command was around 2.319ms. So at idle and and light throttles it would never command less than 2.319ms, EVEN if i commanded leaner AFR in the DVT section of the scantool.
DATALOG ATTACHED
So here's whats weird, IF i turn fuel trims on, it'll pull fuel and idle/cruise 14.6 AFR... some times itll pull upto -70%, the problem with that is then when you tip into the throttle it will hesitate and go lean for a sec before it recovers.
SOOOOO FRUSTRATING!!!!!
Ive been tuning Gen3 LS' stuff for over 10 years, never had this problem before. In fact, Ive tuned multiple trucks also with FIC 95's and never had this problem. I figured there must be an underlying issue, but today I was tuning another car with nearly the same setup (except 5.3 and truck harness) and it is doing the exact same thing to me...
MY BROTHERS TUNE AND A DATA LOG IS ATTACHED
21224
21225