DI, PI and MAF

[Gt86Force]

Hi,

I'm helping a friend to tune his car with ecutek. We have an issue and we don't know if it's hw or sw.

LTFT from idle to 3k rpm is between -2 and -5%
LTFT from 3 to 5k rpm is horrible, between -14 and -17,1%
LTFT from 5 to rev limiter is again between -2 and -5%

In the 3 - 5k range, only DI is active. What could be the issue?
You need to adjust the MAF for both injection systems?
I'm thinking DI injectors leak, but the car is new.

Thanks,

[tomm.brz]

post a log, or you won t getting much help...

[Gt86Force]

Originally Posted by tomm.brz

post a log, or you won t getting much help...

I don't have one right now, but I'll post it soon. The dyno is not available today...

I don't know (and here I need your help) if on this car you need to scale the MAF with only one injection mode activated at the time, or no. If not it's probably an injector leak.

[tomm.brz]

you do not have a leak.
and you do not have to scale maf with just one injection at time, what I can tell you is, the PI is wrongly scaled from facrory, they write 228cc but it tends to lean more than DI, so if you disable the PI on mid rpm, it is gonna pull some fuel ( negative trims) compared to when PI is active

post a log in datazap and link here...

[Gt86Force]

Originally Posted by tomm.brz

you do not have a leak.
and you do not have to scale maf with just one injection at time, what I can tell you is, the PI is wrongly scaled from facrory, they write 228cc but it tends to lean more than DI, so if you disable the PI on mid rpm, it is gonna pull some fuel ( negative trims) compared to when PI is active

post a log in datazap and link here...

ok thanks!
The PI on mid rpm is disabled by factory (injection mode d4s 2), I left the DI/PI ratio stock.
I wasn't expecting -17%, that is a lot of fuel.

[tomm.brz]

if maf is scaled right, also for open loop, is gonna remove some fuel on higher rpm/low load/low throttle ( arround 2.5v-3v), it s normal
anyway i suggest keeping a bit of PI always, even if. it s just a 3-5%, newer calids do also the same

[steve99]

Is the car NA or FI ? Are you using stock injectors. Is the intake stock ?


Is header stock. Do you have catch cans or BOV


Is fuel pump stock
Do you have arround 60psi fuel pressure


Have you altered the 02 sensor scaling at all
Have you altered maf scaling ?


Is you air filter oiled ? Is maf sensor Clean


Check the Direct injection computer has all three mount bolts installed and tight


Are you using ecutek closed loop fueling or speed density ?

[Gt86Force]

Originally Posted by steve99

Is the car NA or FI ? Are you using stock injectors. Is the intake stock ?
NA, stock injectors, stock intake, cosworth air filter.

Is header stock. Do you have catch cans or BOV
hks el gtspec header, no catch cans or bov

Is fuel pump stock
Do you have arround 60psi fuel pressure
stock fuel pump, don't know how to check fuel pressure. on ecutek you can log only high pressure pump and it's following target.

Have you altered the 02 sensor scaling at all
Have you altered maf scaling ?
stock maf and 02 scaling, only disabled cel p0420

Is you air filter oiled ? Is maf sensor Clean
no oiled filter, need to check if maf is dirty

Check the Direct injection computer has all three mount bolts installed and tight
DI ecu is ok, no grounding issues

Are you using ecutek closed loop fueling or speed density ?

Nothing yet, just started logging and noticed the issue in first post. The idea is to ignore CL fueling and SD probably is not necessary in this application, will see.

[tomm.brz]

yes don t stress yourself with speed density, for NA with stock airbox, a good maf tune is enough
if you want more help post a 5 minutes closed loop log and a 3rd gear pull from 2k rpm to redline

[steve99]

Originally Posted by Gt86Force

Nothing yet, just started logging and noticed the issue in first post. The idea is to ignore CL fueling and SD probably is not necessary in this application, will see.

The reason i asked about sd or ecutek cl is that usuong either of those incorrectly can cause fueling issues.


Ok of your car is stock NA its quite unususal for such a large fueing error.


If you go back to stock map for car using stock calid do you still have the large negitive fuel trims in the midrange area.


Dont even add racerom patch just flash a completly stock tune with original calid for car



If the car is using an alternate calid the maf scale can be different.


Exhaust or intake leaks usually send fuel trims very positive at lower rpm.


Look at the actual afr reading at idle, if you see the afr ocilating from very lean to very rich quite quickly then the O2 sensor is likely damaged.

[tomm.brz]

to me is not unusual, but well without log is all words in the air
in my tunes i regularly see a fuel pulling in midrange with low throttle, after i scaled the maf correctly, so i ll wait for the log