sc400 Tuning question
09-10-11, 07:06 AM
#16
The ECU overwriting your tune is a huge problem. Even without O2s my ecu fights my tune every couple of days. I just took a tip from the IS guys and replaced the constant 12v wire on my ECU with a switched 12v so it resets every time I shut off the car.
09-10-11, 11:42 AM
#17
Well my MKIII (before she got hit by the semi) was in fact a turbo 1uz.
On my SC4, I just have an SAFC just cause. So yes, I have done a bit tuning in both areas lol.
My SC just has test pipes, exhaust with no mufflers, and an intake that I made. I did actually tune it with just the SAFC, and had my wideband installed for a few days, and I noted the changes that the car made. I tested my theory that I had on my 1uz turbo supra, on the SC. By disconnecting the CTS was the ONLY way I could get it to stop relearning. On the flip side, start up was terrible. Since the CTS wasn't working, I believe the car defaulted on some -40 degrees and the cold start injector would actually work.
In the time I've owned the car, it has NEVER been cold enough in TX for the cold start injector to work. I used a plastic vice grip on the rubber line to the cold start to stop fuel to going to it, and it got a bit easier to start.
IIRC, the 95+ SC4's dont' have a cold start injector, so this may or may not work for you.
I never got to test the theory on the no CTS with o2 sensors still installed though on my turbo 1uz. On my turbo 1uz, the motor would actually richen up under boost since the AFM was seeing a lot of air. But it never had o2 sensors so I didn't know if the o2 sensors would play a part in adjusting driveablilty
On my SC4, I just have an SAFC just cause. So yes, I have done a bit tuning in both areas lol.
My SC just has test pipes, exhaust with no mufflers, and an intake that I made. I did actually tune it with just the SAFC, and had my wideband installed for a few days, and I noted the changes that the car made. I tested my theory that I had on my 1uz turbo supra, on the SC. By disconnecting the CTS was the ONLY way I could get it to stop relearning. On the flip side, start up was terrible. Since the CTS wasn't working, I believe the car defaulted on some -40 degrees and the cold start injector would actually work.
In the time I've owned the car, it has NEVER been cold enough in TX for the cold start injector to work. I used a plastic vice grip on the rubber line to the cold start to stop fuel to going to it, and it got a bit easier to start.
IIRC, the 95+ SC4's dont' have a cold start injector, so this may or may not work for you.
I never got to test the theory on the no CTS with o2 sensors still installed though on my turbo 1uz. On my turbo 1uz, the motor would actually richen up under boost since the AFM was seeing a lot of air. But it never had o2 sensors so I didn't know if the o2 sensors would play a part in adjusting driveablilty
09-10-11, 11:46 AM
#18
Did you just wire in a switch??
The problem I had was when the car was cranking, no power would be sent to the ECU, so it would start up for a second then die right away. I would have to keep my foot on the throttle until i started. Definitely no way a Lexus should be like that lol
09-13-11, 03:28 PM
#19
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why not run O2 simulators on your stock ecu, wire in wideband O2's to your A/F controller...then your ecu thinks everything is good while your controller adjusts.
any thoughts?
any thoughts?
09-13-11, 03:34 PM
#20
What i dont understand is how the ECU relearns?
If you are using a piggy back such as an SAFC neo or something, Then the ECU is being "lied" too. Say your stock fuel curve runs at 0 when you add the piggy back and tune it for extra fuel say +2 then bassicly the piggy back intercepts the signals and tells the ECU that the fuel curve is at -2. The ecu will counter that by trying to bring it back to factory curve of 0 by adding +2 to it. Bassicly making your car add more fuel...
so how does the ECU learn? how does it completely ignore what is being told to it if it is only being told by the piggy back what to interact with? This is an ECU we are talking about here. It will only react to a signal that is given to it. This isnt some crazy terminator AI here. Im not quite understanding
If you are using a piggy back such as an SAFC neo or something, Then the ECU is being "lied" too. Say your stock fuel curve runs at 0 when you add the piggy back and tune it for extra fuel say +2 then bassicly the piggy back intercepts the signals and tells the ECU that the fuel curve is at -2. The ecu will counter that by trying to bring it back to factory curve of 0 by adding +2 to it. Bassicly making your car add more fuel...
so how does the ECU learn? how does it completely ignore what is being told to it if it is only being told by the piggy back what to interact with? This is an ECU we are talking about here. It will only react to a signal that is given to it. This isnt some crazy terminator AI here. Im not quite understanding
09-13-11, 03:43 PM
#21
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So think about the ECU as a child who has one thing on it's mind...to get from point A to point B on a specified path.
The SAFC is basically a person pulling the child off the path with a piece of candy, and it will work for a little bit. However, the child will look up and see the shiny thing at the end of the path that it wanted to get in the first place so it totally forgets about the candy and goes back to the specified path.
That's the easiest way I can think of explaining it. It's not TX intelligence, but it does try to revert to stock on a regular basis from what I've read/heard.
This is my justification for dropping the cash for a MAP ECU because it does more than just "lie" to the ECU. My 2psi though
The SAFC is basically a person pulling the child off the path with a piece of candy, and it will work for a little bit. However, the child will look up and see the shiny thing at the end of the path that it wanted to get in the first place so it totally forgets about the candy and goes back to the specified path.
That's the easiest way I can think of explaining it. It's not TX intelligence, but it does try to revert to stock on a regular basis from what I've read/heard.
This is my justification for dropping the cash for a MAP ECU because it does more than just "lie" to the ECU. My 2psi though
09-14-11, 09:13 AM
#22
Kinda
On an SAFC specifically, is that the SAFC intercepts the AFM/MAP/MAF signal. So when you lean out the car, the SAFC intercepts the signal and tells the car it's actually receiving less air, so it then lessens the fuel.
Sounds good right? Well here's the underlying problem, once the o2 sensors fire up, and the car is in closed loop (taking in feedback from the o2 sensor) it sees that it's not running to the set parameters in the EE/PROM, then it sends the signal back to the ECU.
Once the ECU sees a something amiss, then it tries to correct, and what the ECU does (as far as toyota) it OVERcorrects it, then slowly backs it down.
So the problem lies in the o2 sensor. That's how ecu works. The problem is, if you disconnect the o2 sensors, the car has a preset map (AKA limp mode), and so if you try to tune it open loop (no feedback) it STILL takes a guess on it, and adjust it on how it wants to be.
The only way I've found is disconnecting the CTS, which makes it think that it's still stuck in cold start and so it never goes into closed loop, and the so it doesn't even realize the o2 sensors arent' even there.
The reason why the car relearns so much is due to the over-programming of the stock computer. Toyota wanted the car to be reliable and smooth, and not even worry about gas mileage (since there wasn't a fuel crisis anymore), and so it was overdeveloped.
On an SAFC specifically, is that the SAFC intercepts the AFM/MAP/MAF signal. So when you lean out the car, the SAFC intercepts the signal and tells the car it's actually receiving less air, so it then lessens the fuel.
Sounds good right? Well here's the underlying problem, once the o2 sensors fire up, and the car is in closed loop (taking in feedback from the o2 sensor) it sees that it's not running to the set parameters in the EE/PROM, then it sends the signal back to the ECU.
Once the ECU sees a something amiss, then it tries to correct, and what the ECU does (as far as toyota) it OVERcorrects it, then slowly backs it down.
So the problem lies in the o2 sensor. That's how ecu works. The problem is, if you disconnect the o2 sensors, the car has a preset map (AKA limp mode), and so if you try to tune it open loop (no feedback) it STILL takes a guess on it, and adjust it on how it wants to be.
The only way I've found is disconnecting the CTS, which makes it think that it's still stuck in cold start and so it never goes into closed loop, and the so it doesn't even realize the o2 sensors arent' even there.
The reason why the car relearns so much is due to the over-programming of the stock computer. Toyota wanted the car to be reliable and smooth, and not even worry about gas mileage (since there wasn't a fuel crisis anymore), and so it was overdeveloped.
09-14-11, 10:47 AM
#23
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Here's the list of features w/ the MAP ECU3
1. USB Interface for out of vehicle config
2. Option WiFi (avail. later)
3. Built in +42 PSI MAP Sensor
4. Additional general purpose Analog Input and Output for FCD, etc
5. Fully configurable Inputs and Outputs, Including TPS and O2 inputs
6. Advanced Launch Control with Speed Input and Timing Retard
7. Advanced NOS activation with RPM, Throttle, Boost and Speed parameters
8. Sixteen operational modes including: MAF Elimination, MAF intercept, TPS load, and more
9. Full timing advance and retard control of up to 8 channels for Distrbutor, Group Fire or Coil on plug confi using a 20 x 19 (380 zone) table
10. Aux injector control using a 20 x 19 (380 zone) table
11. OEM O2 & AFR sensor adjust 26 x 19 (494 zone) table allowing control over Air/Fuel rations, even in Closed-loop mode
12. 10,000 RPM scale
13. 2 complete sets of Fuel, Timing, Aux Injector, O2 Adjust, and EBC tables selectable using a dashboard mounted switch
14. Electronic Boost Control with 1000 RPM target boost points. External and Internal wastegate support including Fast spool mode for Internal Wastegates
15. 2 x Fuel Cute Defeat with overboost safety release
16. Combined Speed Cut Defeat and speed adjust
17. External MAP Sensor option
18. User selectable pressure scales
Compare all of that to an SAFC and I think you'll see a minor benefit
1. USB Interface for out of vehicle config
2. Option WiFi (avail. later)
3. Built in +42 PSI MAP Sensor
4. Additional general purpose Analog Input and Output for FCD, etc
5. Fully configurable Inputs and Outputs, Including TPS and O2 inputs
6. Advanced Launch Control with Speed Input and Timing Retard
7. Advanced NOS activation with RPM, Throttle, Boost and Speed parameters
8. Sixteen operational modes including: MAF Elimination, MAF intercept, TPS load, and more
9. Full timing advance and retard control of up to 8 channels for Distrbutor, Group Fire or Coil on plug confi using a 20 x 19 (380 zone) table
10. Aux injector control using a 20 x 19 (380 zone) table
11. OEM O2 & AFR sensor adjust 26 x 19 (494 zone) table allowing control over Air/Fuel rations, even in Closed-loop mode
12. 10,000 RPM scale
13. 2 complete sets of Fuel, Timing, Aux Injector, O2 Adjust, and EBC tables selectable using a dashboard mounted switch
14. Electronic Boost Control with 1000 RPM target boost points. External and Internal wastegate support including Fast spool mode for Internal Wastegates
15. 2 x Fuel Cute Defeat with overboost safety release
16. Combined Speed Cut Defeat and speed adjust
17. External MAP Sensor option
18. User selectable pressure scales
Compare all of that to an SAFC and I think you'll see a minor benefit
09-14-11, 02:12 PM
#24
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omf god
the apexi afc, safc 1, safc2, safc neo (combine safc 2 with vafc) has been out since the dawn of time.
I have had mine on for 4+ years no problems at all.
The safc modifies air-flow meter signal (pressure signal in some vehicles) to optimize fuel-air ratio.
The second-generation S-AFC is a fuel computer that adjusts fuel/air ratio by modifying the air-flow meter/MAP sensor signal. The S-AFC features a user-definable, eight-point, adjustable fuel curve that can be set in 500 RPM increments.
The range of fuel adjustment is +/- 50% at each of the user-defined setting points. On hot-wire vehicles, the Deceleration Air Flow Correction function is capable of curing the erratic idle and stall problems associated with open-atmosphere blow-off valves on hot-wire air-flow meter systems.
The S-AFC is capable of monitoring and replaying the following data channels in Numerical, Analog Meter and Graph displays: Intake Manifold Vacuum/Boost Pressure, Air Flow Capacity, Intake Manifold Pressure, Karmann Frequency, Engine RPM, Throttle Position, and Air Flow Correction %.
The soarer ecu does not and cannot "retune" at all.
The soarer ecu does not and cannot "retune" at all.
The soarer ecu does not and cannot "retune" at all.
The soarer ecu does not and cannot "retune" at all.
+/- few degrees ign timing depending on engine temps (every ecu has that feature)
when you increase or decrease the fuel% it does affect the ign timing (every ecu does that) but you are manually telling the safc to tell the computer to change.
you can install up to 25% bigger injectors and have the safc go to -15% on the fuel curve and that will be the new 0% base
safc is so underated
the apexi afc, safc 1, safc2, safc neo (combine safc 2 with vafc) has been out since the dawn of time.
I have had mine on for 4+ years no problems at all.
The safc modifies air-flow meter signal (pressure signal in some vehicles) to optimize fuel-air ratio.
The second-generation S-AFC is a fuel computer that adjusts fuel/air ratio by modifying the air-flow meter/MAP sensor signal. The S-AFC features a user-definable, eight-point, adjustable fuel curve that can be set in 500 RPM increments.
The range of fuel adjustment is +/- 50% at each of the user-defined setting points. On hot-wire vehicles, the Deceleration Air Flow Correction function is capable of curing the erratic idle and stall problems associated with open-atmosphere blow-off valves on hot-wire air-flow meter systems.
The S-AFC is capable of monitoring and replaying the following data channels in Numerical, Analog Meter and Graph displays: Intake Manifold Vacuum/Boost Pressure, Air Flow Capacity, Intake Manifold Pressure, Karmann Frequency, Engine RPM, Throttle Position, and Air Flow Correction %.
The soarer ecu does not and cannot "retune" at all.
The soarer ecu does not and cannot "retune" at all.
The soarer ecu does not and cannot "retune" at all.
The soarer ecu does not and cannot "retune" at all.
+/- few degrees ign timing depending on engine temps (every ecu has that feature)
when you increase or decrease the fuel% it does affect the ign timing (every ecu does that) but you are manually telling the safc to tell the computer to change.
you can install up to 25% bigger injectors and have the safc go to -15% on the fuel curve and that will be the new 0% base
safc is so underated
09-14-11, 03:50 PM
#25
See this is where i get confused. Iv been doing Hours and hours of googling on the SAFC I,II and the NEO and there is always alot of good information but it seems to be 50/50. some people love it. Others hate it.
I want to make this clear, The NEO would only be a band aid to get the car running and enjoy for a little bit untill we Up the boost, do fuel mods and a stand alone.
Im planning on getting a AEM supra TT ecu and having it rechipped to an 8cyl model. Thanks to Scotturnot for the help on this one. So in the end the car will be stand alone.
I just wanted to see if the Neo was even worth playing with. i would have it for like 6 months or so just do enjoy the car. I wanted to hear peoples Personal experience. Not what they have heard.
Thank you for the response's that were given though
I want to make this clear, The NEO would only be a band aid to get the car running and enjoy for a little bit untill we Up the boost, do fuel mods and a stand alone.
Im planning on getting a AEM supra TT ecu and having it rechipped to an 8cyl model. Thanks to Scotturnot for the help on this one. So in the end the car will be stand alone.
I just wanted to see if the Neo was even worth playing with. i would have it for like 6 months or so just do enjoy the car. I wanted to hear peoples Personal experience. Not what they have heard.
Thank you for the response's that were given though
09-14-11, 07:45 PM
#26
I'm pretty sure it does, I can actually prove it. Anytime you make an adjustment on the SAFC, watch your wideband gauge.
Once the car is in closed loop, lean or richen it all the way up. You'll see shortly that the car will slowly send it back to 14.7
I've tried this over and over, and that's how I know that the only way to stop it is by disconnected the CTS. Do it at idle, and let it run for 30 minutes, and I guarantee that it will go back to 14.7-15.0
I don't know if the soarer ecu is different than the sc400 ecu, I doubt it though.
Also, when in my MKIII I could get the car to run 12:1 under WOT, then after a few days, under close conditions, the car would slowly lean out after a few pulls.
How would you explain that is "just a timing" thing?
I'm not here to badmouth or get into an argument, just want to get facts straight. There are many turbo 1uz guys that have this issue, I think the only way of combating the relearn feature is a piggy back that can simulate the o2 signal, or intercept it.
JDM MUSCLE
If you want a band aid fix, I think a FMU may be up your alley
Once the car is in closed loop, lean or richen it all the way up. You'll see shortly that the car will slowly send it back to 14.7
I've tried this over and over, and that's how I know that the only way to stop it is by disconnected the CTS. Do it at idle, and let it run for 30 minutes, and I guarantee that it will go back to 14.7-15.0
I don't know if the soarer ecu is different than the sc400 ecu, I doubt it though.
Also, when in my MKIII I could get the car to run 12:1 under WOT, then after a few days, under close conditions, the car would slowly lean out after a few pulls.
How would you explain that is "just a timing" thing?
I'm not here to badmouth or get into an argument, just want to get facts straight. There are many turbo 1uz guys that have this issue, I think the only way of combating the relearn feature is a piggy back that can simulate the o2 signal, or intercept it.
JDM MUSCLE
If you want a band aid fix, I think a FMU may be up your alley
09-14-11, 10:57 PM
#27
It will only correct itself to stoich during closed loop just as you said. When you go into accel enrichment mode (aka open loop), the ecu stops taking advice from the 02's and then your S-AFC corrections are used.
JDM you are making the right decision with the standalone. Sorry I haven't been able to reply to your PM. I haven't had much spare time.
JDM you are making the right decision with the standalone. Sorry I haven't been able to reply to your PM. I haven't had much spare time.
09-15-11, 08:37 AM
#28
Then how do you explain the car running lean after x amounts of WOT pulls??
Again, I'm not trying to get into a pissing contest, just trying to iron this out with everyone else's experiences.
I know even my SC4, it doesn't stay at the 13:1 area all the time on WOT
Again, I'm not trying to get into a pissing contest, just trying to iron this out with everyone else's experiences.
I know even my SC4, it doesn't stay at the 13:1 area all the time on WOT
09-15-11, 03:10 PM
#29
I do agree that attempting to either lean out or enrich the A/F curve on these engines during closed loop operating will not work because the ECU will just increase its correction factor to get the signal back to 14.7.