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Hi all,
New to data scan, so please excuse my lack of knowledge. I have a 300zx tt manual and would like to know if I can check the fuel mixture under varying conditions. Thanks in advance everyone.

I don't believe so. What problem are you having?

Not so much a problem as more curiosity really.
I have just replaced both 02 sensors and wanted to check their functionality using Data Scan.
I also fear that I may have a small air leak somewhere, which in turn may lead to running too lean.

You can check that by looking at the o2 sensor function on bank 1 and 2. As long as they fluctuate between .1 and .9 volts very quickly, the o2 sensors are good. In turn that would correct you air fuel ratio to within specs as long as fuel pump and pressure regulator are good.

Cheers Onephatser,

Really appreciate you help. I will hook up Data Scan as you say and check out the sensors.
On a separate note, I am a little unsure as to whether or not my AAC valve is working correctly.
Could someone explain it's exact function and what I should be looking for please?
Is there a specific multi meter check I could perform as to determine if the required voltage is there for example?

The AAC actually stands for auxillary air control valve. It's basicly an Idle control valve. I've never seen one completely fail. They do get dirty though. Take the valve off and clean with carburetor cleaner where the plunger is. The only test I'm aware of is to hook the valve to a 12v source and see if the plunger open and closes all the way.

Cheers,
Ken

the AAC valve can be ordered in active test
if the motor reacts is that the valve operates
a cleaning of the valve is a good

for the sensor O2, he should the engine speed to 2500rpm
for motor control of wealth
you need a wideband O2

seb.racing wrote:
> for motor control of wealth
> you need a wideband O2

Innovate WB kits are working with Datascan software without of problem, You can log everything together .

The AAC valve is located on the upper intake plenum. Are you having a problem with an unstable idle?

Thanks guys, some very usefull information for me to look into.
As for my idle oneohatser, these are the results. from cold she always starts first time, it's just that the tick over starts at 1200rpm and does not return to 750rpm untill she is fully up to temperature. As you can imagine, this may take a long time during these cold mornings, and as I have a difficult gearbox, it is made more troublesome to change gear due to the high tick over. Surely it should not take that long to settle down?