I just hooked up my A/F meter today and have some questions on how it should be running. While the car is idleing, the meter is RAPIDLY fluctuating between full stoich and full lean. Also while driving when i let off the gas the meter will go completely dead until i hit the gas again (then it goes to one bar rich, one bar stoich). Is this how the gage is suppose to operate? If not, how should my gage look while my car is running? Any help would be appriaciated, since I am new to air fuel gages.
Yeah Sounds about right to me, unless you get a wideband that A/F just looks nice.
Sounds about right....
Under decel, throttle closed, the fuel is shut down so it goes blank,
Under cruise, it will quickly swing between lean and the upper part of the scale. Thats the EEC reacting to the A/F ratio in closed loop.
Under boost, the A/F gauge should go to Green, rich.
Those are the two uses I have for these A/F gauges. Under cruise, you can keep it in closed loop for gas mileage. The other is that it will indicate a problem if it doesent go rich under boost.
Bob Myers
HEY SPOOLER :I READ IN ONE OF MESSAGES IN THE SEARCH MODE THAT HOOKING THE WIRE UP TO THE #29PIN,ABOUT 6in.UP FROM THE HARNESS IS THE HOT SET UP.CHECK IT OUT. LOU
Yea Idle and cruising speeds the A/F swings to lean rich several times a second. WOT it should obviously go rich.
Apparently the A/F gauge is almost usless on a narrowband sensor. With a wide band you would be able to see the exact ratio and it not "bouncing". This is b/c the narrow bands reads narrower range of A/F ratio mixture.
One good thing about the gauge with a narrow band is it does tell you when your going lean, ie running out of fuel, starving the pump, blown IC hose are some examples. I am always looking at my gauge.
My "useless according to some people" narrow band AF gauge saved my a$$ today..... I always take a quick glance at it when going into boost, especially over 10 psi. As I looked at it, it was full rich, and as boost hit 15, it started to drop way lean. I let off, and then slowly boosted it up while watching my FP gauge. Fuel press increased 1:1 with boost until I hit 13 psi, then fuel press started to rapidly drop to mid 30s psi. CRAP!!
Fuel filter not plugged, and pump seems noisier than usual.... time to drop the tank and have a look.... my guess is either the pump is FUBAR (Walbro 255 HP with only about 40K miles on it
), or the filter sock is plugged. At least the problem happened now, and not in a month and a half while on the road to / from Carlisle!!
This also proves what I have said hundreds of times in posts about fuel problems.... fuel pressure at idle or at cruise tells you almost nothing.... pressure MUST be checked under boost / WOT to show up problems.
I'm with Jeff. My useless narrow band saved my engine when I forgot to plug the reference line back into the FPR and went out on the back roads for a little test & tune. Needless to say fuel pressure did not rise with boost pressure.
I was actually running out of gas when my gauge was running lean so I knew it was time to fill up.
See besides to cool factor it does serve a purpose.