Tuning SAFCII in 4g92sohc with Custom turbo

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cygee26

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Mar 22, 2017
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Hi,

My car has this specs
4g92sohc (cb4a)
390cc low impede injectors
TD04HL-15T-5(cartridge)
TF035HM-13T(turbine and comp housing)
Manual turbosmart boost controller(+3 set)
External turbosmart wastegate

Previous piggyback system: safc dials(no issue aside that in rich in fuel)
Current piggyback system: safc2(prompt to upgrade to correct rich issue but getting idle to stall concerns)


My question is why my engine Stall even im getting good idle 780-880rpm as if its choking

Sensor type Karman
No knocking sensor

12 ne points set
800rpm -33L-30H
1000rpm -33L -30H
1800rpm -33L -30H
2200rpm -33L -30H
3000rpm -32L -29H
3600rpm -31L -28H
4000rpm -30L -27H
4600rpm -28L -26H
5000rpm -28L -26H
5600rpm -28L -26H
6000rpm -28L -26H
6600rpm -28L -26H

Throttle point 30Low 70High

Dec.-Air
Throttle 1.0%
Ne1 6.0%
Ne2 8.0%

Im complete out of options to check how to correct the idle-stall issue.
 
jack be nimble said:
You need a wideband o2 sensor to tune a safc properly
Click to expand...
Yes... going to that approach... but right now i cant maintain idle without engine stalling in random

Karman sensor selection take away the dec.-air option that will help regulate air

If the car is running or above 1600rpm everything is smooth.

Only when i reach idle 800rpm-1600rpm it has this "choke like" manner that if it cant be compensated by pressing the thottle it will stall.
 
the ISC is it a 6 wire? if so did you cut the 2 center wires alot of aftermarket ecu's use 4 wire idle control and you have to adapt you 6 wire into a 4 by cutting the wires to pins 2 and 4 (check that the safc is the same before you do this). if the safc is expecting this the ISC might not be operating correctly leading to a stall condition due to a realy tightly set BISS
 
Ian91 said:
Reset base idle and test the tps and isc are operating right?
Click to expand...
i will check on this later tonight or tomorrow

leadfoot said:
the ISC is it a 6 wire? if so did you cut the 2 center wires alot of aftermarket ecu's use 4 wire idle control and you have to adapt you 6 wire into a 4 by cutting the wires to pins 2 and 4 (check that the safc is the same before you do this). if the safc is expecting this the ISC might not be operating correctly leading to a stall condition due to a realy tightly set BISS
Click to expand...


i will double check BISScrew and seems i had that tight.

thank you
 

Attachments

  • SAFC1 and SAFC2.jpg
    SAFC1 and SAFC2.jpg
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from your image DO NOT cut the 2 wires i suggested as your factory ecu still controls those.

you've actually compounded your issues you've increase the injector size and are intercepting and altering the aiflow sensor signal i think you'll find you are actually running WAY to rich.
 
leadfoot said:
from your image DO NOT cut the 2 wires i suggested as your factory ecu still controls those.

you've actually compounded your issues you've increase the injector size and are intercepting and altering the aiflow sensor signal i think you'll find you are actually running WAY to rich.
Click to expand...
we tried that as well when we install SAFC1 5Dials but the outcome is having the engine to stall (check engine indicator is up)

we haven't tried with SAFC2 as we follow the diagram (see attachment)

and your correct i'm running WAY to rich without AFR installed yet and just observing the Fuel Level
Before(City 8-10km/L and Long Drive 12-14km/L)
Now(City 4-6km/L and Long Drive 7-9km/L)

I expected the outcome. but not to much difference (is the goal)
 

Attachments

  • SAFC2 Wiring Diagram 2 Approach.jpg
    SAFC2 Wiring Diagram 2 Approach.jpg
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  • SAFC1 Wiring Diagram.jpg
    SAFC1 Wiring Diagram.jpg
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So if you're running stock ecu and stock injectors, why are you compensating at idle?
I use to tune my vr4 with safc 2 but instead of throttle signal I used boost signal from my aftermarket map sansors. That way you compensate only as you go up into boost but cruise and idle remains unchanged.
 
vr401 said:
So if you're running stock ecu and stock injectors, why are you compensating at idle?
I use to tune my vr4 with safc 2 but instead of throttle signal I used boost signal from my aftermarket map sansors. That way you compensate only as you go up into boost but cruise and idle remains unchanged.
Click to expand...
Hi im running stock ecu and upgraded my injectors from 180cc high imped to 390cc low imped
Everything is wired correctly but even at idle it stall or in random while running it "choke"

Setting of safc2 as of now (0130H Local Time)
Karman sensor selected
4 cyl and throttle up
Throttle point: 30%Low and 70%High
NE Points / Low% / High%
1000rpm / 34 / 32
1600rpm / 34 / 32
2200rpm / 34 / 32
2800rpm / 34 / 32
3400rpm / 33 / 31
4000rpm / 32 / 30
4600rpm / 31 / 29
5200rpm / 30 / 28
5800rpm / 29 / 27
6200rpm / 29 / 27
6800rpm / 29 / 27
7400rpm / 29 / 27
7200rpm / 29 / 27

Later today i will have this checked woth an AFR installed

Im read other articles and they saying it something related to "BoV recirculating setup"

Im using the following
HKS SSQV BoV Black (vent to air) pull type
External wastgate
Manual Boost Controller (set to +3 click to max limit to 0.8kg/cm2)
* im running on stock engine internals 4G92NA and stock FP(for now)

Other articles suggesting "blow Through" setup as by default MAF499 is a "Draw Through" setup

Right now im completely out of options as why its stalling while idle and in random and its "choking" when running or on idle.
 
update with "choke behavior" after upgrading from SAFC1 to SAFC2

using an AEM AFR
and adjusting NE points 800 idle to -49%
AFR = 15.2
but in random during the "choke" occurrence the AFR drop to 11
this time its not stalling but still "choking"

if the AFR = 10 or more than that(10 is the lowest reading it can get) that's the time it stalls

additional information i'm still using Stock Fuel Pump when its still a 4g92NA

is it possible my Pump cannot compensate on the instruction given by SAFC2 to the ECU?

should change my pump to higher LPH?
 
no i think you'll find that because of the size of your injectors you can't pull enough air value to result in a low enough injector setting. perhaps try the 310 cc n/a 4g93 injectors instead of the turbos 390's lower than 10:1 on regular is SUPER rich hell with the AFR's your getting you could run e85

your other option is to delete the SAFC and do what another guy did get a CAS from a dohc machine it to fit and run coil packs and a factory 4g93t ecu
 
something also just occured to me if the SOHC 4g92 is anything like the 4G93 sohc then the injectors are banked the ecu only realy sees 2 injectors and fires cylinder 1/4 together and cylinders 2/3 together so you are essentially pulsing those BIG 390's twice which is alot of fuel for that little engine to swallow. this further leads me to think you simply can't compensate enough fuel out
 
leadfoot said:
no i think you'll find that because of the size of your injectors you can't pull enough air value to result in a low enough injector setting. perhaps try the 310 cc n/a 4g93 injectors instead of the turbos 390's lower than 10:1 on regular is SUPER rich hell with the AFR's your getting you could run e85

your other option is to delete the SAFC and do what another guy did get a CAS from a dohc machine it to fit and run coil packs and a factory 4g93t ecu
Click to expand...
im using 390cc Low Imp DSM injectors
im looking for 275cc or hopefully 310cc(but rare from my area)
common that can be found is 240cc, 390cc and 510cc(i got this 1 as well on stock from evo3)



leadfoot said:
something also just occured to me if the SOHC 4g92 is anything like the 4G93 sohc then the injectors are banked the ecu only realy sees 2 injectors and fires cylinder 1/4 together and cylinders 2/3 together so you are essentially pulsing those BIG 390's twice which is alot of fuel for that little engine to swallow. this further leads me to think you simply can't compensate enough fuel out
Click to expand...
Recent Update:
we did a downgrade of injectors from 390cc to stock 182cc
tuned the safc2 but still gettings the "choked" behavior but as long the AFR reading doesnt hit 11 or 10. its tolerable
but if A/C is on. then again its "choking"

is my MAF449 has issues? or SAFC2 is so sensitive?
would it help if i rewire and change to MAF609?
 
what happens if you pull the SAFCII out? on stock injectors? it should idle and free rev fine with out it as the table should have plenty of headroom to compensate for the turbo airflow. (obviously dont try load it up or go into alot of boost) although you could technically drive it and monitor AFRS since all airflow reading are done PRE turbo.
 
leadfoot said:
what happens if you pull the SAFCII out? on stock injectors? it should idle and free rev fine with out it as the table should have plenty of headroom to compensate for the turbo airflow. (obviously dont try load it up or go into alot of boost) although you could technically drive it and monitor AFRS since all airflow reading are done PRE turbo.
Click to expand...
SAFCII out = all is good with AC Off.. but AC On its seems fine but A/C Economy mode "Amber" RPM is Erratic

Update as of 06/19/2017
SAFCII is working now
= minor choke on low throttle but with high throttle(pedal to floor) everything is working fine

390cc(DSM) low Impedance
Grams 255LPH Fuel Pump
New Throttle Idle Speed Control Servo Kit
NGK BKR7E-11 Spark Plug

little to no hiccup (little more fine tuning needed on low throttle settings)

im glad that its now running while A/C is on.
 

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