Tech Writeup: SAFC install on 1996 Subaru Impreza L

[teh DIRT]

MY quest to make this forum the greatest area to come for online automotive research area has begun...FOLLOW MY LEAD!:

Today I tackled the install on my ej22e. While it is pretty straighforward if you know what you are doing, Apexi's instructions are for japanese cars...and the american instructions dont really explain it all. So here goes my tech writeup.

WARNING: THIS MODIFICATION CAN CAUSE PERMANENT DAMAGE TO THE ECU, ENGINE, AND OTHER PARTS IF DONE INCORRECTLY. DO NOT ATTEMPT THIS INSTALLATION IF YOU ARE NOT SURE ABOUT WHAT IS INVOLVED.

Tools Needed:
1-10mm socket and ratchet
1-roll of electrical tape
1- wire stripper
7-quick strip wire connectors
1-S-AFC super air/fuel computer

Prepping Installation:
1. When doing any work on your car it is advised that you disconnect the negative battery terminal. To do this, locate the negative battery terminal and loosen the terminal clamp using a 10mm socket. Remove the clamp and place it aside where nothing will come in contact with it.

2. All of the work for this installation will be done in the front passenger footwell. You will need to access the ECU (engine control unit) under the carpet.

3. There are two clips that hold the carpet in place. They are both visible by looking at where the carpet ends as it goes under the dashboard. One is on the left and the other on the right. They can either be unscrewed or popped off. Remove these clips

4. Pull the carpet down. It may need to be pulled out from behind the plastic panel on the left. Pull it down far enough to expose the ecu kickplate cover.

5. The ECU kickplate cover is held on at 4 points. 3 of these points are bolts that can be easily spotted. The last one is a nut that is at the highest point of the kickplate. Remove all of these using a 10mm socket. Pull the kickplate off slowly and place it aside. Your ECU should be visible now.

6. The ECU may have a platic bag like cover on it. Take that off and place it aside. The maing wiring harness inserts into the ECU on the passenger side of the unit. The the top of the unit there should be a white lever that is facing upwards. Turn that lever counter-clockwise to unlock the harness from the ECU.

7. Pull the harness out of the ECU. The harness is ziptied to the floor infront of the ECU. While it is not neccesary to remove this attachment, it makes it much easier if you do so.

Installation:

There are seven connections with 5 wires that need to be made. These connections should be made with these:
http://i2.photobucket.com/albums/y2/96imprez/safc010.jpg

Many owners who have S-AFC opt to soder their connections. This provides a cleaner connection and is safer agaisnt having a wire come loose. It is not necessary and if you are planing on un-installing the S-AFC, it is just adding time to that process.

These are the connections:

http://i2.photobucket.com/albums/y2/96imprez/wireconfig.jpg

1. The SAFC red wire needs to be spliced in with the ECU yellow wire (pin 85)

2. The SAFC green wire needs to be spliced in with the ECU red wire (pin 64)

3. The SAFC grey wire needs to be spliced in with the ECU green wire (pin 6)

4. The SAFC brown wire needs to be spliced in with the ECU black wire (pin 94), closer to the ECU

5. The SAFC black wire needs to be spliced in with the ECU black wire (pin 94), farther from ECU. (after the brown wire)

6. The SAFC yellow wire needs to be spliced in with the ECU pink/blue wire (pin 5), closer to the ECU.

7. The SAFC white wire needs to be spliced in with the ECU pink/blue wire (pin 5), farther from the ECU (after the yellow wire)

7a. After the yellow and white SAFC wires are spliced. Cut in between them. Be sure to tape of the ends.


8. After all the connections are made, check over all of them to make sure that the wire is actually exposed. I had to take all of the wires out and strip a bare spot in them because the quick strip connectors werent cutting through the outer wire cover.

9. Plug the entire ECU harness back into the ECU and rotate the lever clockwise until it locks.

9.At this point you may want to re-connect the negative battery terminal and make sure that the S-AFC is wired properly.

10.Turn the key to on, DO NOT START THE CAR. The S-AFC screen should light up and "SUPER AFC" should appear then fade into "A-PEXi"
http://i2.photobucket.com/albums/y2/96imprez/safc001.jpg

[teh DIRT]

Set-up
1. Setting up the Sensors

Maf-Sensor
http://i2.photobucket.com/albums/y2/96imprez/safc013.jpg
http://i2.photobucket.com/albums/y2/96imprez/safc014.jpg
http://i2.photobucket.com/albums/y2/96imprez/safc015.jpg
http://i2.photobucket.com/albums/y2/96imprez/safc016.jpg
http://i2.photobucket.com/albums/y2/96imprez/safc017.jpg
Select 'etc.' [next]
Select 'sensor type' [next]
Select 'Hot-Wire' [next]
Set In and Out to: 4/4 [next] (this can be played with a little. The voltage changes are slight between the choices, but it does make a difference.)
Set sens. cal to :1/1 [prev][prev][prev]

Car Type
http://i2.photobucket.com/albums/y2/96imprez/safc018.jpg
http://i2.photobucket.com/albums/y2/96imprez/safc019.jpg
Select 'Car select' [next]
Set Cyl to '4' and Throttle to 'upward arrow' [prev]

Sensor Check
http://i2.photobucket.com/albums/y2/96imprez/safc020.jpg
http://i2.photobucket.com/albums/y2/96imprez/safc021.jpg
Select Sens.check [next]
Note: when '0' throttle is applied the voltage should be between '0-.45'
when 'full' throttle is applied the voltage should be between '3.7-3.75'
[prev]
[prev]

[teh DIRT]

2. Settings

Before starting the car it is best to make sure that all fuel corrections are set to zero. It should be this was when you receive it but it is wise to make sure.
http://i2.photobucket.com/albums/y2/96imprez/safc022.jpg
http://i2.photobucket.com/albums/y2/96imprez/safc023.jpg
http://i2.photobucket.com/albums/y2/96imprez/safc024.jpg
http://i2.photobucket.com/albums/y2/96imprez/safc025.jpg

Select 'settings' [next]
Select 'Hi-Thrtl' [next]
Set all RPM ranges to '0' [prev]
Select 'Lo-Thrtl' [next]
Set all RPM ranges to '0' [prev][prev]

Clean-up:

1. Depending on where you want to mount your S-AFC, you need to run the wire to that location and make sure that it wont get caught anywhere by moving parts or passengers feet.

2. Replace the plastic ECU cover that was removed during installation prep.

3. Re-install the kickplate and make sure it is secure, check to make sure that the S-AFC turns on after the kickplate is re-installed. There is a chance that the kickplate could cause a wire to shift or short.

4. Re-install the carpet and screw/push the clips back in.

[teh DIRT]

Tuning:

1. Tuning should only be done by a professional tuner during a dyno session.

2. If you feel like you would be able to tune your S-AFC by yourself it is HIGHLY helpful to use a wideband 02 sensor to monitor you A/F ratio.

3. Without a wideband 02 sensor...you run the risk of tuning to lean and destroying your engine.

Bad Tuning= http://www.rs25.com/forums/images/smilies/blowingup.gif

Good Tuning= :drag:


HAPPY TUNING!


-pete

[KrautFed20V]

Good Writeup, maybe this could be a start to an "install" section???


just a thought

:thumbup:

Nice work pete

[2point4DSM]

-Super AFC Tuning Tips-

Purpose:

The Air Flow Converter takes the pulse (frequency) from the Mass Air Flow meter and either speeds it up or slows it down at different RPM points to make the ECU run the injectors either richer or leaner. All by itself, it can only give you a little more bottom end power by leaning out the mix some. If you try to richen the top end you will just hit fuel cut (100% fuel inj. pulse) sooner on most turbo cars.

The best use for the AFC is to install larger injectors (runs richer) and then adjust the AFC leaner to compensate. This also raises the point where you run into problems with the ECU (lower frequency Hz).

The Super AFC also allows for two different maps according to load. It makes the load calculation based on the Throttle Position Sensor. You choose what is high and what is low. We normally set it for 30% low and 80% high.

Initial AFC Tuning (Low):

While in neutral, try revving the engine to the exact RPM settings on the AFC. Hold the RPM, and then start playing with the setting for that RPM. Listen to the exhaust. Start on the rich side, the engine will likely sound very "smooth". Slowly work your way lean, you'll start to hear misfires (popping sounds). A good point is probably where things just start to pop a little but are pretty close to "smooth" (rich). Watch the O2 sensor voltage or A/F ratio meter. Normally the voltage will swing back and forth between .2 and .8 volts at idle and part throttle cruising. . As you adjust leaner, the ECU will compensate back richer. Slowly click down leaner so that the LEDs do not come up. You will then see the O2 voltage come back up slowly. This is the ECU re adjusting. Keep going down until the ECU can no longer bring the A/F ratio back up to swinging in the middle LEDs (.2-.8v). From there richen that rpm point back up about 10 percent. That should put you pretty close to 0 to 5% fuel trim at the ECU.

Next repeat the same thing driving the car on the freeway. Hold the car at the rpm that you are going to set. Note what percentage you are beginning with and slowly go lower until the ECU can no longer richen things back up. Go richer about 10% more and compare that with the compensation percentage that you started with. You should be fairly close.

When you get things too far out of whack, you will most likely get a check engine light code for Fuel Trim. It just means that the ECU was trying to adjust things to get back between 0.2 and 0.8 volts and couldn't. Don't panic, this is normal. Try to figure out where you were too lean or rich and fix it up. Re-set the ECU and see if the code re-appears.

Initial AFC Tuning (High):

The higher rpm ranges on the AFC are probably the easiest to tune (if you have an EGT). Use 3rd & 4th gear and go for long runs & watch your EGTs... If the temp gets over 900 Celsius in third gear, you are too lean. We've found that above 5,000 rpm, the settings are typically set very similar to each other.

The 2,000 to 3,000 rpm ranges are more tricky because you rarely stay in those RPM's for long & the EGT really won't help you. They'll likely be a little leaner than the higher rpm settings. The 4,000 and 5,000 RPM settings are the most important for maximum power and safety. Typically that is where you first punch the throttle when racing and also where the rpms fall back to when you shift.

Try to borrow a digital volt meter meter for your first major tests to prevent against grossly lean situations.

Ultimately it comes down to a lot of fiddling around over time. When cruising around, note the RPM's you are at and when you stomp on it, and pay attention to the next two thousand RPM's (it's important to concentrate on RPM ranges and not just overall acceleration...) You start to pick up on when the car is being held back by timing (lean) or if it's running fat. The exhaust sounds a little different (softer) & the power delivery feels different too.

Tuning With O2 Sensor Voltage:

The stock O2 sensors are not very well matched between vehicles. They will give reasonably repeatable numbers run after run, but you can not compare your numbers with that of another O2 sensor. There are a few O2 sensors that have instrument grade accuracy but they run $800 and up. They also have a very short life span at that accuracy. Oxygen sensor voltage output will also vary with the temperature of the sensor. High end O2 sensors and their monitoring devices have complex circuitry to compensate for this.

The Blinky Light meters out there like Cyberdyne, Autometer, and EFI's Dual Meter are perfectly accurate at reading the voltage from the O2 sensor and lighting up the proper LED. The problem with them is when relying on them for full throttle tuning is that the range is not fine enough. There is a huge performance difference between .90v and .96v. Both of those voltages will light up the top most LED on these gauges. The LED based gauges do have their purpose in tuning closed loop/part throttle at a glance. For more accuracy a wideband meter is best.

Tuning with is fine with your own O2 and multi-meter but the numbers you are reading really have no relationship to anyone else's numbers to within .02v.

High EGTs and Knock:

If you are running too lean for the boost and octane you have in the tank, you will get knock or pre-ignition. The knock sensor bolted to the engine block will pick up this "pinging" sound long before you can hear it inside the car. When under higher boost, there is almost always small amounts of knock. At these small amounts of knock the ECU will continue to advance timing normally. At mid knock levels the ECU will hold timing and if it gets too high or rises quickly, the ECU will begin to retard timing if not pull it all the way back to zero. You can hear the exhaust note change when the timing goes away. It will turn deeper , almost rumbly sounding. When the timing is retarded, the ignition process happens so late that the flame front shoots out the exhaust port when the exhaust valve opens and blows still expanding, really hot gas directly onto the EGT probe. So internally the pistons are barely warm, but the exhaust manifold and turbo get real hot. This is the reason we recommend not running EGTs higher than 900 degrees C. That is the point that timing retard is usually driving the EGTs up. Not that immediate damage is being done, it is just that you are no longer making additional power above that temperature and there is no benefit to running there.

"I turned up my boost and the car does not feel any faster"

The power can drop off after a while when increasing the boost due to intercooler flow and intake temperature. The trick is to find the lowest boost that still feels strong. You might as well run just what boost you need to make power rather than stressing the turbo and chance detonation on pump gas. Now with race gas it is a different ball game and the max power point should increase so you will want to try turning up the boost another 2 PSI or more.

(source: RRE)

[SexyDSM95]

Yuck! IMHO, I don't like splitters. I soldered mine...good write up Pete.

Lean is mean!

P.S. Tuning blind is a bad bad bad bad idea. (Hint: Get some sort of data logging material) I know from personal experience, not everyone can destroy aftermarket injectors =P

[teh DIRT]

Well done. Thanks for the follow up....with this thread alone. Anyone should be able to use an S-AFC safely. Mods doing what Mods should do.
-pete

edit: yeah alot of people have sodered their connections....but ill be taking it all out eventually and doing it again so I didnt feel like breaking out the sodering gun.

[SexyDSM95]

edit: yeah alot of people have sodered their connections....but ill be taking it all out eventually and doing it again so I didnt feel like breaking out the sodering gun.
Oh yea then I definately would have done the same thing. And just a side note (just in case) some of the diagrams in the Apexi directions/booklets that come in the box, diagrams are either wrong (pin connection count wise) or the diagrams are backwards.

If you have some sort of vfaq, forum with members who have done it, or just try to google it to confirm the diagrams the Apexi booklet has for your specific vehicle.

[teh DIRT]

yeah that is why i did this writeup, the instructions were unclear and I had to do a lot of research and checking to get everything right.

[2point4DSM]

I've got a butane powered, cordless soldering iron if your interested. Works pretty good. I got it off the Snap-On truck.

[teh DIRT]

I have one also, I am just not soldering it in until the new engine is in and wired. Thanks though
-pete