Safc on a 97 obd2 sc400??

xspsi6

New Member
I am wondering if I could get away with this but I am thinking most likely not:mad:

I am looking for a piggyback air/fuel unit to help with the p1sc I plan on putting on my sc400 soon but right now I am asking questions to get my ducks in a row before I dive head first in to this.

Would like to hear any feedback on the subject as it seems everyone is using an a pre obd2 car that I can see so would messing with the hotwire maf signal interfere with the timing as I know Toyota used to like to do things this way.
 

stevechumo

Active Member
The tuner must know a trick to tune the SAFC, so that the OEM ECU doesn't relearn after reading the O2 signals. There're more than a handful of late OBD2 SC300 and Tundra using SAFC out there from what I know. I believe there're some O2 sensor simulators that can be used to trick the ECU that it won't know the air/fuel has been changed.
 

spf_lexus

New Member
If the safc can read AFR through a wideband, then like Steve said.. yank the o2's and stick simulators on them. Problem solved. If the piggyback needs the oem o2's to function, you might have to try another route.
 

4U2QUIK

Approved Vendor
If the safc can read AFR through a wideband, then like Steve said.. yank the o2's and stick simulators on them. Problem solved. If the piggyback needs the oem o2's to function, you might have to try another route.
SAFC will not work properly on odbII vehicles because it does nothing with the air temp sensor, which in turn will let the ecu know something is up and it will compensate/relearn. also Safc does not have any input from the o2 either. The apexi safc's are mostly meant for honda's. if you want to tune the uz engine i reccomend a maft system like the maft pro. or the maft II if you're on a budget.
 

stevechumo

Active Member
SAFC has been used on SC3, SC4 on N/A (my friend did it on 93 - OBDI unfortunately), Supra MKIII, MKIV, IS3 (all on OBDII), and Tundra (OBDII). The SAFC actually is used to trimmed down/ increase the fuel pulses of the injectors, but it doesn't do anything to the timing. However, the timing may be changed due to the reading from the O2 sensors. The OEM ECU will alter the timing to compensate for the A/F. So if the O2 simulators are used, they'll trick the ECU to feel like it's normal. That won't change the timing.
 

spf_lexus

New Member
So if the O2 simulators are used, they'll trick the ECU to feel like it's normal. That won't change the timing.
Steve, I wonder if you can "tweak" the oem o2 readings up and down with the simulators in order to play with the stock timing?
 

stevechumo

Active Member
Steve, I wonder if you can "tweak" the oem o2 readings up and down with the simulators in order to play with the stock timing?
I'm not sure if you can do that. I don't think you can tweak it because if the ECU reads something different from within its parameters, it'll throw the timing and the worst thing is it'll pull the fuel and give you CEL. That'll be bad under WOT. The simulators are used to cheat the ECU, so that you can run bigger fuel injectors and use the SAFC to control it without letting it know. And if it knows, it'll mess up.
 
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