Ok...

Driving around the other day I get a CEL. A/F guage startes weirding out too. All the lights are coming on if at all. Or my favorite they all disapear. I bust out the trusty PocketLogger (thanks run4cvr) and it pulls PO171 which = System too Lean (bank 1).

In my infinate wisdom I determine that bank 1 is the front O2 sensor. I take a look at it and idiot me ran the wires right across the downpipe. The outer mesh insulating material = Ka-Char. I cut that stuff away the 4 wires look alright. Their insulation looks pristine and undamaged. So I reroute it the right way and not going directly across the downpipe. Cleared the CEL with the pocketlogger and went on my merry way.

At idle the pocketlogger sees .24v to .82v at idle on the front O2 bank. I drive it around nicely and the car is running fine and no CEL. Then I get on it and take it to WOT. The car is still running great but the logger shows 0.00v on the front O2 reading. The car still didnt throw a CEL and I'm hearing no knock or seeing no hesitation. Accel pump is still sounding good (raped pig). A/F guage is still freaking out. During deceleration the A/F gauge reads so lean the meter shows no lights at all. wtf? I checked the connection to the ecu and it looks good. During WOT the A/F read pretty rich. Its just any other type of driving all the lights on lean to stoich are on.

I'm running pretty rich right now. around 58-62 idle fuel PSI and at WOT full boost It sees around 120 PSI fuel.

Now, every once in awhile the car bogs at idle and wants to die. I dont have to gas it to save the car but it does bog. does it for like 4 seconds then it starts to run fine again.

I'm just a little lost cause the car isnt throwing a CEL again but I expect it will. Is the front O2 sensor bad? I'm just trying to troubleshoot this abit as I'm a little tapped for cash at the moment.

Any input would be greatly appreciated.
If I'm missing any info let me know and I'll try to grab it.
I'm still a n00b at this so be nice :)

I believe the exposed wire may have shorted out the O2. Test the resistance on that O2 man. And 120psi? Is that your fuel pressure? You're overworking those injectors man. I hope it's not stock. Because over 100psi on stock injectors or any injectors and that thing just starts to bog and perform real crappy.

I dunno about that cuz the hahn instruction say quote

"Intercooled systems will run at 8 to 9 pounds of boost. At nine points, you must see 105-110 PSI fuel pressure."

What car is this on?

99 RS w/ Hahn Stage II w/FMIC. Only thing I changed with the kit is that i went with a Missing Link.

i have the same error code but i am non turbo. you said you checked the front o2 sensor. mine is fairly new, 3 1/2 months old but brand new from the dealer. i still got some other idea's on why mine is running lean but let us know how it goes with the CEL.
later

Hrm...i think i might be stuck swapping o2 sensors...its just that the car is running great and no more CEL but the a/f guage is still wacko...

I think the stalling might be due to your high idle fuel pressure. As for the wierd o2 readings... anyone else?

Ok Ok, I'll lean it out a bit :P

but i still find it odd that the pocketlogger was showing the front o2 sensor reading 0.00v at WOT....

Hey,

I had that exact same problem. I threw a code system too lean and my car started to hesitate, stutter. I had the EGR replaced thinking that it was causing it. It was leaking so it had to be replaced anyways. Drove around for a bit and everything was great. Then I am driving and my O2 sensor at idle was reading 0.2V and not going up if I revved it. I would get on it, EGT's normal everything fine but the O2 sensor was maxed at 0.3V, wierd I thought. Wehn I let off it, the damn thing showed -1.8V!!! I was like holy shit, look up at the EGT's everything is fine!! I replaced the O2 sensor and drove it for a couple of weeks with no problems, my car idled better, ran better, just overall was better and I was getting normal O2 readings. I think it is your O2 sensor. I moved to Florida shortly after I replaced it so long term I cant comment but the car was perfect before I left.

well, i tested the wires to the o2 sensor and 2 out of 4 werent showing any current throughput...spliced into them with some new wire...cleared the CEL. Now my idle voltage is .74 on the front o2. Tonight I'm gonna take it to WOT and see where my voltage is. and oh yeah, back off the fuel a bit too.

ARG!

Brand new o2 sensor installed. Idle fuel pressure is at 50 psi, under WOT 7 psi boost I hit 105 psi on fuel. Car is running great under throttle.

Come to a stop after load, car bogs a few times, All the lights on the A/F guage are going off and the car throws the p0171 CEL again.

I'm totally lost.

At idle my front o2 voltages are bouncing between .2 and .7....at WOT im sitting at .95 to 1.05 v.

Whats going on?

The KS is jealous of the SRT, mang. :P bump?

So you arent getting the 0.00v at WOT anymore?

>So you arent getting the 0.00v at WOT anymore?

no, im getting .95

On a whim I decided to gank the A/F guage.....

Oh my fucking god it worked. Either a shitty wiring job on the gauge or the gauge itself is pooched. No CEL, great o2 voltage readings and best of all, do bogging down at idle. Thx autometer.

Whats this whim's name? :-p

>Whats this whim's name? :-p

Mr. Lack of nicotine and fucking pissed off the III