Today I installed my Apexi SAFC 2, and so far it has worked pretty well. I really want to figure out more about the knock sensor function, and various other settings.

1) I showed sx7r the spec sheet people have been using, but neither he nor I use 4 in, 4 out. We both use 1 in, 1 out, so maybe it's a '99/5th gen issue.

2) On the knock sensor function the lowest I can get it to go is 1350rpm, and the highest it goes is 3650rpm. The raw data reads fine, and the "knock" increases as the rpms climb as it should. Using the knock sensor reading the number is always 0 above idle, but went up to 6 at idle. I believe I read that this monitor number is in percentage, so maybe that's why it never goes above 0. Where did people read about setting the knock sensor in neutral up and down, and then under load through certain rpm ranges?

3) Does anyone have any voltages for their O2 sensor reading? I believe the O2 voltage shows under Sensor Chk as In2 (I believe). According to the FSM the O2 sensor should read 0-0.3 and .8-1.0 in closed loop mode. Right now I'm 1.3 so I'm definitely rich even if the OEM O2 sensors are off :P

4) Does anyone know what In 1 is? I believe it's the MAF reading, but I haven't gone through my FSM yet to see what the MAF readings should be to compared with the reading on the SAFC.

Finally, I'm disappointed that I can read the O2 sensor voltage but not log it or even view it in anything but Sensor Chk. The OEM O2 sensors aren't great, but at least I could get a feel for whether I'm running lean or rich a la the Autometer A/F gauge.

Any comments, thoughts, or insight on the SAFC 2 is appreciated.
-hype

 

Ok after reading the Japanese SAFC 2 and American SAFC I manuals 4 in 4 out is correct for tuning fuel, but 1 in 1 out will allow the car to run. Therefore make sure you check the settings.

Has anyone tried to tune their partial throttle A/F?
From http://www.prostreetonline.com/pso/p...to/tuneafc.asp

Tuning without a Datalogger

Life is much easier with a datalogger, but not everyone has one. To tune right the car will need some way to view O2 sensor voltage (see Blue Wire info above), and an Exhaust Gas Temperature Gauge with the probe preferably mounted somewhere in the #1 or #2 exhaust runner. For the LO map, start at idle with the engine fully warmed up, and set 1000 RPM until the O2 voltage is cycling up and down and not holding a fixed value. Usually the O2 voltage will be switching back and forth between .3 and .7 volt. This as discussed above is referred to as Closed Loop operation. Once the O2 voltage is cycling, reduce the AFC setting until it stops cycling, then increase the setting until it starts cycling again, then add another 2 clicks on the AFC setting. With the Idle now set, cruise at a constant low throttle for each of the remaining RPM points and do the same. Cruise along at 2000 RPM until the O2s are cycling, then lean it out until the O2s stop cycling, then add fuel again until it starts cycling and then go another 2 clicks up. Do this for 2000-4000 RPM. With the cruising area set, take the 4000 RPM value and use that for 5000+, all on the LO map.

This makes sense to me, and should help with gas mileage because the ECU isn't having to compensate as much each time it's in closed loop mode. The only concern I have is that I recall people mentioning the ECU resetting itself if you adjust the fuel too much under partial throttle (or something like that). Would anyone care to comment?

After reading I realized that In 1 is the MAF voltage. In 2 is usually only used on cars with 2 MAFs (300ZX, etc.), but by attaching the blue wire to the O2 wire we can view the OEM O2 sensor voltage. This is why you have to go to the Sensor Check menu to see the voltage, and you're not given a A/F option to view on the graphs or meters. This isn't incredibly practical, but can give you an idea on what your OEM O2 sensors are reading if you don't have an A/F gauge (like me).

Any additional comments, thoughts, or insight on the SAFC 2 are appreciated.
-hype

 

Yeah, how do you get the knock feature to work? I only get the raw reading : I went into the knock setup menu and revved at the 2 rpm points listed there, but nothing happened (the numbers next to each corresponding rpm remained at zero).

 

I went to the knock sensor setup and revved in neutral and didn't get much knock (the settings didn't set either). Next I went out on the street and went WOT in 4th gear at low rpms so the knock sensor would read. If you hit right -> while WOT the setting will set, and the reading will change.

The lowest I could get the low reading to go was 1350, but I didn't see how high it would go. Next do the same for the 2nd setting, but (I'm assuming) go higher in the rpms. The highest I could get setting 2 to go was 3650.

I'm still learning what raw knock sensor numbers are normal, but I'm getting a feel for it. At night my knock numbers are around 48 starting out, and max out around ~150. During the day they're much higher; coming home from work today in 99 degree weather I hit 322@2800rpm on the highway in 5th gear and 288 at 1800 in 4th gear on city streets.

Right now we need to compare raw numbers because the knock number on the monitor mode is (I believe) an estimated percentage of the number you should be getting at a given rpm.

What I really need is some education on knock. I understand the concept, but what affects knock:
I know temperature does, but do things like rpm, throttle %, load, etc? Also I would really like to know what our car's timing does at idle, closed loop, WOT. Sometimes I see more knock at idle than under low throttle %
-hype

 

Hype you ask hard questions and I am still learning this stuff.

On the blue wire mod, I initially had mine hooked up and used it to view one of the front O2 sensors but the readings were the same as the ones on my OBDII reader and I heard from the DSM guys that hooking up to it can affect the readings going to the ECU so I have since removed it. In the same fashion they said the same thing about the knock sensor wire so I have removed it too.

The readings from the O2 on my car were in the late .8 range ie .88-.89 and of course this only works at WOT otherwise they just cycle up and down.

I've ordered a wideband O2 because the narrow band ones are so inaccurate at the 12 A/F range that they are totally unreliable and they are also very temperature sensitive.

This is the wideband I am getting. http://wbo2.com/

On the part throttle question. My understanding is that the ECU will reset any changes from around 36% and lower so that is the reason for the 39 Low throttle and 40 high throttle settings.

 

I know I ask hard questions, and I'm used to getting no responses I'm just trying to get discussion started so that maybe we can figure some things out.

Mine are already hooked up so I'll probably just leave them since I have no OBD logger. They're in parallel, so the voltage drop should be very minimal anyway.

According to all my sources that's about where you want to be. On a wideband O2 you want to be right around .86V, but I agree that the OEM O2 sensors are off. I can't afford a wideband, but I have gotten to be around an FJO several times. Let us know how your wideband is though because that's a great price. The widebands I've always seen come in right around ~$700.

This makes sense since closed loop is pretty efficient, but it seems like I should be able to dial down the fuel some to help get a more stable stoichiometric mix since I am about 6psi over stock fuel pressure.

Overall I seem to be getting consistant knock sensor readings depending on the ambient temperature and throttle %. If I had a few more people to compare numbers with maybe we could figure something out. Part of my problem is where to set my "base" settings for the knock sensor function. If I set the settings during the day my raw knock number is as high as ~300 whereas at night my numbers are more like 50. I'm leaning towards setting the settings during the day so that I'll know if/when I go over a worst case scenario settings (hot temperatures/WOT).
-hype

 

My KS readings seemed to be ok at first but I noticed that the further I drove the higher they became. Have you tried driving for an hour or more and watching the readings? They do seem to go up and down when reving etc but I didn't like the fact that they kept climbing over time.

I am trying another KS here soon so I will see if it reacts the same.

 

I have noticed the KS readings do increase over time, but eventually mine seem to level out. I drive a half hour to work everyday, and they stay constant once they increase some from the idle numbers. I'll be driving to Austin on the 26th, so I'll keep an eye on the numbers to see how much the knock raises over the 3 hour drive.

Right now I'm logging (manually recording) my KS readings in the morning, afternoon, and night at idle and WOT so I'll report back.
-hype