AEM F/IC Documentation Link

Posted by & filed under AEM F/IC, EFI Tuning.

I’ve been researching the AEM F/IC for a 1JZ single turbo tune I have coming up.

AEM FIC Tuning Tips

Posted by & filed under AEM F/IC, EFI Tuning.

AEM FIC Tuning Tips


There has been a lot of questions about tuning the FIC. I’ve went through a lot with the FIC and this is what I came up with.

Special thanks to JeffTsai, TeckIS300, and the my.is community for this post

So you have a vvti 2jzge? decided to go FIC with it? Double checked your wiring? You are half way there. Make sure you update the latest firmware and use the latest software to give you less headaches.

The FIC tuning tip document supplied by every FIC unit is a must read. It will give you a good insight on how piggyback tuning works.

Use the stock Bank 1 Senor 1 o2 sensor, and hook up the FIC skew to it (don’t forget the resistor). Then wire the B2S1 sensor signal to the B1S1 sensor. You would also want to run a dual-output o2 simulator for the Sensor 2s. Except for B1S1, use a resistor on all the heater circuits (if the circuit is present). Do not splice heater circuits to each other because this will cause a drop in resistance, and trigger CEL.

Calibrating your MAF in its new environment

Before anything, you compensate in the MAF voltage map (not the MAF fuel map). Stock intake pipe diamater is 2.75″, and more than likely you are running a 3″ MAF charge pipe. To compensate for this difference, add 9% to the entire MAF voltage map. I had the worst problems with idling because i neglected this step.

Select All -> Right Click -> Set Value -> Enter “9” -> Press OK

You are done with the first step.

Update: the MAF pipe from stock is about 2.75″, not 2.5″, so 9% would be the sweet spot to get your fuel trim smack on [(3-2.75)/2.75]

MAF Clamp

Next step is MAF voltage clamp. Your MAF tells your ECU how much air is flowing, thus the ECU adds fuel accordingly to your MAF reading. Don’t think your MAF just sits there and does nothing; that is how your ECU tunes its AFR. Our ECU tunes the way how we want our AFR to be already; NA IS/GS300s do hit 11.5:1 on WOT.

There are several points where you can clamp your MAF voltage, but I recommend letting your MAF operate as much as possible. You want the stock system to be in control for as much bandwidth as it can handle. Good place to clamp is 4.7V. No need to hide boost from the stock ECU. As far as it’s concerned, it’s just more air and it will pair fuel with whatever it reads accordingly.

MAP load fuel map

MAP Fuel map lets you:

1. change injector size.
2. create a base fuel map (for those that are clamping MAF from seeing boost)
3. fine-tuning.

My AFR is on target by letting my MAF doing most of the work. I also don’t have to worry about fuel trim related issues because that is all worked out between the MAF and the stock o2 sensor.

O2 Skew

To keep the fuel trim +/- 3%, here’s a very simple rule that has worked out for me so far.

Lets say i need to add 3% on the fuel map because of a lean spot, at the same cell, I would put -3% on the O2 skew map. When you are 3% more on the fuel trim, you want the o2 sensor to see 3% leaner.

Ignition
Can’t really tune this unless you are on a dyno with kick-ass knock sensors hooked up. But if you know you are knocking (and your CR is kinda high), then pull some ignition timing.