Sesshoumaru

iTrader: (1)

How does the split air affect the o2 readings if it pumps after the sensor and dumps directly into the cat? I'm not very familiar with stock systems as they have been absent for a while.

Icemark

Because unless the split air is switched to send the pump air to the cat, if the relief valve is closed (all RPMs under 3800) the air pumps into the exhaust port, except on lift throttle.

WAYNE88N/A

Mark, you know, I don't like to portray the appearance of arguing with someone, but the funny thing is most of what you said ^ is exactly what I was saying, you're just looking at it from a different angle...

To make it easy, look at the S4 FSM wiring, page 50-28...The circuit we're concerned with is pin 1I at the ECU, down the wire to the switch, then to ground. Obviously the load of the circuit is internal of the ECU, or it would be a direct short when the switch closes (or, it could be external, another solenoid somewhere, maybe?)...

Now, if we get 12v at that ECU pin, the switch is open...

If we get 0v, the switch is closed, I think we both agree on these points...

Now, the FSM has you test for 12v in 5th gear (see page 4A-30, among others). That means the switch is open. Therefore, the switch is closed in every other gear, and open in 5th, contrary to what conventional wisdom dictates...

You need to explain to me how the O2 sensor changes resistance due to the split air flow downstream of the sensor, also- I don't get that one (or are you taking the switching valve directing port air into the rotor housings, then towards the sensor in consideration?)...I think you also meant voltage, too, that's what the O2 sensor produces, not resistance...

I've been working with wiring on aircraft forever, I've been working on all my cars' wiring since my teen years, and I wired my own house as I built it...Although I'll be the first to admit I'm not perfect, none of the above has burned to the ground yet, therefore I'm pretty sure I know what I'm doing...Cheers