7romanstatesmen

iTrader: (1)

i read shureshot's thread on how do do this...

https://www.rx7club.com/showthread.p...ighlight=apexi

but the writeup was for s5's, and i can't find the info on which wire to use for the pressure sensor on an s4 n/a. another interesting thing is that my tps readings are even more wrong than normal. when i'm not even touching the gas pedal, the readings are between 15 and 20%. the 100% mark on the s-afc comes with *maybe* 10 or 15% actual pedal travel, as opposed to the normal 30 or 50%.

NZConvertible

That is perfectly normal with the S4's narrow-range TPS, which only measures the first quarter or so of throttle travel. This is the main reason to use the MAP sensor instead of the TPS on S4's.

The procedure is exactly the same for S4's and S5's. All you're doing it tapping the S-AFC's throttle signal wire into the ECU's MAP sensor wire instead of the TPS wire.

7romanstatesmen

iTrader: (1)

wow, thanks. that's a very useful diagram. i'll be fixing things shortly.

edit: you disconnect the s-afc from the tps wire if you use the afm signal, right?

NZConvertible

I don't think you fully understand what the S-AFC does. It intercepts the AFM signal and alters it, so there is no "if" about using it. You have no choice about that, it's simply the way it works. The TPS signal is simply what the unit uses to swap between the low-load and high-load correction curves. For the S4 though, the MAP sensor output gives a far better measure of actual engine load than the narrow-range TPS does.

So you have to connect both AFM wires and the TPS wire as per the instructions. The only difference is that the TPS wire is connected to the MAP sensor signal wire instead.

Ottoman

How do we correlate the "psuedo TPS" % ?

for example.. if i remember correctly the map sensor goes to 1 bar right?

the high map will start as soon as u hit 0.1 bar? i.e. positive manifold pressure?

obviously 1 bar=100%

so is 0 bar 0 % or something in the Vaccume? diff cars pull diff levels of vacuume depending on the health of the engine...

seems a little inconsistant...

can u elaborate some more NZ

NZConvertible

The most important thing to remember is that NA's and turbos will have completely different settings. Obvious but important anyway. Where you set the high and low points should also be done during dyno tuning, not by guessing or picking some arbitrary points.

I'm not sure how low the MAP sensors can read to, but it's safe to say you'll never see a 0% "throttle" reading because you can't get near absolute zero pressure. For an NA with an idle vacuum of say 16inHg you'll see ~40%, but less than that under decel. Full thottle will instantly give nearly zero vacuum, and since the NA MAP sensor only reads up to 2-3psi positive pressure, you'll get a reading of 80-90%. For an turbo, which has a -1bar to +1bar MAP sensor, the same 16inHg idle vacuum you'll see ~20% (less under decel). Your max boost will determine the highest "throttle" reading you see, with 10psi showing ~80%.

7romanstatesmen

iTrader: (1)

sorry, i meant the pressure sensor (same thing as map i believe...), not afm

NZConvertible

Ah, I see. So you're connecting the S-AFC's grey wire to the wire on pin 2B instead of 2G.