When i start my car, it runs extremely rich (all the way rich on my A/F gauge) but as soon as it warms up, and the rpms drop to a little below 1k, i start to run so lean that it cant register on the gauge anymore.... then when i give it gas, it runs just above stoich while on the throttle, but as soon as im back down to idle, it runs lean again.... i havent let it run for any bit of time when it runs lean bc im afraid of burning up an apex... what could be problem???

 

bump.... i really need help with this.
What wires do i need to tap into to get a voltage reading? there are 4 wires going to the fuel pump, so i dont know which ones i need to connect to the volt meter.
thanks

 

What does it do while driving? AF guages are not completly accurate since they are relying on the stock sensor to give you info. I'd say first action is to check your fuel pump voltage, FPR, PD, and injectors. If all that is good then Go to a dyno and have them hook up the wideband to your car and see what the wideband says compared to your little light array.

 

which wires do i use for the volt meter?

 

When the car is cold, and you start the car, the airpumps air is sent overboard to the airpump silencer. So no/not much airpump air is sent to the EXAUST ports.

When the water warms up, and the water temp switch in the radiator senses its warm, the Relief solenoid then applies a vacuum to the acv's relief diaphram and now....airpump air is sent to the EXAUST PORTS.

The EXAUST PORTS are located upstream of the 02 sensor.

It's the additional air at the EXAUST PORTS that makes the 02 sensor read lean AFTER the car warms up. Its the LACK of that airpump air that makes the 02 sensor read RICH during the cold idle.

Try this///// after the car warms up, and the afr reads now lean....go pull the BLUE plug off the RElief solenoid. Now the afr should read .....RICH once more.

That is how a series four car should react when it is in stock condition (read NORMAL CAR).

 

my car isnt stock, and i no longer have an air pump... so what can i do now???

 

Your car is not going to chuck an apex seal running lean at idle. The worst that can happen is that it will sputter and stop.

If it idles decently, then it is getting enough fuel, no matter what your narrow range 02 sensor tells you...

 

The O2 sensor does not work properly until it reaches operating temp. Ignore anything the A/F gauge says for at least the first five minutes.
Sounds perfectly normal to me. It should only read rich under load, i.e. acceleration.
Lean mixtures are only dangerous under load. At idle the mixture isn't that important as long as it idles okay.

 

oh .. ok
thanks

 

what other alternatives are there to the stock O2 sensor? and aftermarket one?

 

All single-wire O2 sensors are basically the same thing. A generic aftermarket one works no different to stock one, but is much cheaper.

 

http://www.rx7store.net/product.asp?0=208&1=361&3=788

 

Bosch makes a fine unit for approx twenty bucks. PePboys/Autozone/your favorite auto store.