Ok, when I'm idling my fuel pressure guage says I'm at 54 psi. When I drive around town, my A/F guage is saying I'm running lean. WTF? is going on? Do I need a new FPR or what? I've got the one that comes with the HRC Stage 2 kit. The only problem I'm having is fuel pressure....will getting a different FPR solve my problems? If so, what should I get or do? TIA!

If you are cruising around town at less than about 80% throttle, then your ECU is working in closed-loop mode. It is reading the O2 sensor and adjusting fuel. The A/F guage will indicate a cycling from lean to rich while this is happening. The ECU is smart enough to figure out what it needs to do to get your car to run.


Corbin

'95 ESI-T
HRC+FMIC+ETC...

So you're saying that I should be running ok then and that my A/F guage is just for sits and giggles? :)

afaik, the only thing a blinkylite a/f gauge is good for is at WOT (pedal to the floor) ONLY, and ONLY the last 5 green lights.
... so at WOT if you have:
2 or less green, youre lean
3 green, you're good
5 or more green, you're rich

or something like that. all it does when "cruising round town" is sweep back and forth to tell you your O2 sensor isn't bad, and that knight rider isn't dead. ;)

LoL about Night Rider comment. Well, my guage is set up like this....at the bottom (Lean) are to 2 red bars...then 2 orange ones (starting to run lean) above those...then 2 green bars (which is where I should be) then 2 orange bars (starting to run rich) and then 2 red bars at the very top (Which means I'm Rich). Usualy when I'm boosting the guage shows either the first green bar or both bars lit which means I'm running ok when boosting, but when cruising around town say 50-70% throttle it goes towards the 2 orange bars in the lean side. That's why I'm confused as to if I'm running lean or not. Last time I pulled my plugs about one week ago, they were white...which meant I was running way lean. Since then I've turned my idle fuel pressure up and messed with my boost fuel pressure....but I haven't checked my plugs yet. I'm also wondering if maybe my injectors are bad seeing as how I haven't changed them since I got the car.

On my datalogs, whenever there's some vacuum (cruising, slowing down) my o2 voltages drop to .01 or something (corresponds to really lean on your gauge) and flatline there. You'll also notice the ECU gives you hella timing at the same time... like +25 degrees or so (can't remember exact number).

Basically, I'm guessing there's so little exhaust coming out and/or it's being burned so efficiently, that your o2 sensor doesn't read anything. I bet as soon as you punch the pedal up 10% or so, it'll swing back up.

If you're worried, try using a known good o2 sensor in both locations, and see if it changes anything.