Riddle me this: s15 injectors in ka with NO fuel correction???

[TNathe]

So yeah, I need a little help here fellas. This totally baffles me.
First, my setup:
-9.5:1 Wiseco pistons in built engine (ka24de 98yr model)
-480cc s15 injectors w/walboro fuel pump
-z32 MAF
-SAFC w/ PLX Wideband

It isnt turbo'd right this second but ALL the supporting hardware is installed, including the intercooler and piping with just an air filter and MAF on the hot pipe. SAFC is setup properly w. 2in 5out for the MAF. Right now I am running at 0% fuel correction and that is where it runs best at. As a take away fuel (should be -%48) it leans out obviously and starts stumbling till i turn it up (done while idling).

Can anyone EXPLAIN this phenomenon? The only thing I can conclude is the injectors arent said 480cc, but yet they are pink and Ive found images just like them on teh googles.


Another question :) , anyone know how to TEST their wideband o2 sensor? My wideband only goes to 13.1 at FULL LEAN, I have a cheaper air/fuel guage installed also which is getting its reading from the ECU. A the narrow band guage falls off the lean side of the map the car begins to die (obviously) but the wideband only runs back to 13.1 When driving the wideband usually reads about 10.0 - 11.0 even though the car is running fine and the narrowband agrees with the car.

Im stumped...
can an ECU "learn"?

[LigouriRd]

All the ecu's do learn the car's fuel trim. I have heard of people putting in 370's on a stock ecu and the computer trims the fuel back so that one could drive to the dyno for more extensive tuning. I guess it is possible that the ecu is trimming the fuel by itself but to the point of running at stoich (14.7) I doubt it.

I tend to think your wideband is reading correctly and the engine is running rich from the big injectors. What you could try to reset the ecu by leaving the battery unplugged for a night. The next day fire it up and see if you still need zero correction on the safc under cruise conditions. With my '96 ecu and a z32 maf I needed -30% correction for 370cc injectors on a 2in 6out setting. If I remember correctly 2in 5out needed even more correction.

As for your wideband, I would recommend running through the trouble shooting section from here: http://www.plxdevices.com/InstallationInstructions/SM-AFRUsersGuide.pdf
It should read between 10 and 20 afr, if yours caint go through that range then there is a problem.

[garagelu]

s15 injectors are not pink. They should be a brick red color.

[S14Serge]

And aren't s15 injectors 440cc injectors?? Oh well guess I must of
Been wrong about that.

[Grenade180sx]

i fail.. ill stfu HAHA

[bardabe]

z32 setting should be 2in 6out

S13 Sr20 2in 6 out.
KA24 S14 2in 5 Out.

[TNathe]

All the ecu's do learn the car's fuel trim. I have heard of people putting in 370's on a stock ecu and the computer trims the fuel back so that one could drive to the dyno for more extensive tuning. I guess it is possible that the ecu is trimming the fuel by itself but to the point of running at stoich (14.7) I doubt it.

I tend to think your wideband is reading correctly and the engine is running rich from the big injectors. What you could try to reset the ecu by leaving the battery unplugged for a night. The next day fire it up and see if you still need zero correction on the safc under cruise conditions. With my '96 ecu and a z32 maf I needed -30% correction for 370cc injectors on a 2in 6out setting. If I remember correctly 2in 5out needed even more correction.

As for your wideband, I would recommend running through the trouble shooting section from here: http://www.plxdevices.com/InstallationInstructions/SM-AFRUsersGuide.pdf
It should read between 10 and 20 afr, if yours caint go through that range then there is a problem.

thanks! Ill try that and see how it goes.

[LigouriRd]

S13 Sr20 2in 6 out.
KA24 S14 2in 5 Out.
According to Apexi (spoke with them myself), in the S14 chassis the SR20 uses 2in 5out with the z32 maf. 2in 6out for the ka24de with the z32 maf. Regardless, if you are close to zero correction then leave the in/outs alone. That will give you the most range to tune.

[TNathe]

really, 2in 6out? Thanks for the info! Was not aware of that and there is a LOT of mis-information spread then.

[TNathe]

sure enough resetting the ECU and making the adjustments before I started the car yielded the results I wanted. -48% and it runs and drives like it should :) I also made the change to 2in 6out while I was at it. Thanks fellas :)