I hooked up a Zeitronics to my car for a bit today. I was wondering if anyone can tell me if this looks right? I hear our cars are supposed to run really rich, but this looks about right to me.

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The directions said it was supposed to be 10 inches from the exhaust port, but this was only hooked up 8 inches from the exhaust port in my available bung on cylindar 4.

only the afr was hooked up.

I'd like some help understanding what I'm looking at here. I get great gas milage, around 36 highway.

Why do people say we run "pig rich"?

 

Looks like your sitting in a driveway with no load revving the motor. You need to have a load on the car to get an accurate determination of you A/F.

When people talk about our cars running rich they talking while driving the car, drive with the A/F gauge installed and mash down on your gas. I guarantee you see a massive dump of fuel on your A/F gauge.

 

When you hit the throttle in the engine bay your monitor peaked at 11.8ish.... If you don't see taht as uber rich for n/a then you are crazy ;P

A good a/f ratio for n/a under load it 13.7 I believe.

 

In closed loop it will always dither around stoich, that's the only thing it can do with narrowband sensors

It probably runs rich at high loads when it runs in open loop

 

^^ What he said. No load, no point.

 

Reiterating three things that have already been mentioned, albeit in a different way:

In "closed loop", the computer will maintain stoichiometric air/fuel ratio via the feedback loop generated by your upstream O2 sensor. You will never get it out of "closed loop" mode while stationary and revving the motor.

In "open loop" (ie, under 100% throttle), the computer defaults to the stock-programmed fuel maps with correction provided by the combination of short-term and long-term fuel trim maps it has generated over the last 1,000 and ~100,000 engine cycles. This is where the A/FR goes "pig rich", typically to the tune of 11:1 or thereabouts last time I had a wideband hooked into the stock computer setup.

I ended up needing to remove a whopping 17% of my fuel at the ~5500RPM (and higher) region. You think you get decent ileage now? Just wait until you get your load maps corrected.