Ok, i need a n00b explanation on this a/f gauge. It came with the car, and I don't actually know if it's even wired correctly. Anyway, the a/f gauge stays pegged all the way on rich (just 1 green light all the way down buried in the "rich" section of the gauge). It never moves, not during idle, under boost, nothing. there is also an safc installed (which I also haven't touched yet, as I've had zero experience with them). I'm really looking for a quick rundown of what this a/f gauge SHOULD be doing. The mods on the car that matter are a full turbo back RB exhaust, cone filter intake, walbro 255, 750cc marren injectors in the secondaries, and the untuned safc. I'll also mention that there is an EGT gauge as well... when just cruising it stays at about 550....when under boost it goes to maybe 600-650. Are these normal temperatures? Anyway, give me some basic info on these topics.

 

sounds like its not connected right, check to see if you 02 sensor is connected and then check to see if the wire coming form the gauge that goes to th ECU is connected

 

The ECU normally runs stupidly rich. However, it should be showing other things under other conditions.

With the engine off (but the ignition on), the O2 sensor will not be putting out a voltage. This should show up on the gauge as full lean. If the gauge is NOT doing this, then it's miswired or something is really messed up somewhere.

With the engine running, the A/F gauge will be buried rich except for the following cases:
Engine over 1500 RPM, throttle closed. This condition should result in a complete fuel cut (unless the TPS is misadjusted), and a full lean reading.
Light throttle cruise under 3500 RPM: The A/F meter should bounce rapidly (3+ cycles/second) between rich & lean. This is "closed loop" mode, where the ECU actually listens to the O2 sensor for suggestions on fuel delivery.

If it's not doing that, something is wrong. If it doesn't show full lean with the engine not running, troubleshoot wiring, else consider the TPS adjustment & actual condition of the O2 sensor (they get old & stop responding as quickly as they should, or worst case stop responding at all).

-=Russ=-

 

yea...the wiring is jacked up...cause it never leaves full rich...with igntion on (car off)...I've yet to see it move at all...just 1 solid green dot on full rich no matter what. Doesnt' surprise me tho...the boost gauge and egt gauge had to be redone as well already. So one more gauge to get right I guess.

 

the sensor wire is probably plugged into a 12V source. I'm guessing the gauge has 3 wires coming out the back - one for ground, one for 12V source, and one for the 02 sensor?

 

The AF gauge should cycle between lean/rich @ idle/cruise as the O2 sensor it reads from cycles. If you're pegged at rich, try replacing the O2 sensor.

 

Yeup. There's your problem.