arobb

Hello all. I am having some problems with my 02 gs3. I don't know if I'm in the right section for this question but here goes. What I have is an 02gs na-t, I am basically stock everything for now. The only thing that I have for tuning is an Apexi AFC2 & AEM widban. I deleted all 4 of my O2 sensors, but I'm having tuning issues. Can anyone steer me in the right direction on this please!?

mex lex

iTrader: (4)

Plug your primary o2 sensors back in, you can sim your secondary o2 sensors and leave them off.

Ditch the AFC2 and get at least an AEM FIC or Greddy E-Manage Ultimate. Or if you want go all out, go the standalone route like an AEM EMS.

And last but not least find a good tuner that knows what he is doing to tune it for you.

http://www.tokensolutions.net/produc...-optional.html

arobb

I really appreciate the time u took to respond to my post. I did once plug my primary o2's in, but the car started to drive like crape! It wouldn't even go over 3000 rpm's. So ur right, standalone it is...
By the way, if I was to get an E-Manage wont I just have the same issues with the stock ECU? I mean wont the ECU just fight the E-Man?

JeffTsai

iTrader: (1)

If it's tuned correctly, the FIC or Emanage will work fine. Getting the car running correctly is like 20% in the wiring and electrical, and 80% in the tune. I got all my cars to run great with the piggyback systems.

arobb

Thanks for the info Jeff. I have the same sport design & same year. What engine management are you using? You said that you've used piggybacks on your other builds; how did you get around the factory ECU relearning the stock settings? I mean, I can sit and watch the wideband and watch the air fuel all over the place under idling and normal cruising. Under boost though it's fine!

AZTurbo

iTrader: (10)

x2...........

99 GS3

iTrader: (14)

You can get a good tune on stock ecu and piggyback if you hook up the primary o2's and use a live data scanner to see when the car is in open or closed loop and adjust the trims accordingly.

Changes you make when the system is open will stay reliable, but any adjusting you do in the closed loop status will get skewed off because the ecu is trying to target an afr from the o2 input. This is what o2 skew is for in piggybacks like the fic or mapecu.

By disconnecting the primary o2's you force the ecu into fixed map mode, which does work for stopping the tune from changing, problem is that the ecu has 2 fixed maps, cold start and hot start. And your tune has no way to differentiate between the two. This is where you may read about people doing the ecu power relay or coolant temp sensor mods trying to get around that issue and be able to run in fixed map mode consistently. It may work for some but it can affect starting in varying climates and also you may get worse gas mileage (not that mileage should be a big concern on boosted cars)