Running Lean, need help

[5_spd_pewter_v6]

My SES light went on and I had the codes read. I got these:

P0151 - Heated O2 sensor - circuit low voltage Bank 2 Sensor 1
(i don't really understand what that means, so please explain if you can)
P0171 - bank 1 lean
P0174 - bank 2 lean
P0446 - EVAP vent system performance
(i don't understand what this means either, so please explain if you can)

I have a 2000 firebird with pacesetter headers and Y pipe. No cat, an O2 sim on the O2 sensor behind where the cat should be, and I have the EGR port on the hears blocked off (the EGR into the intake just sucks regular air). also, i do have a slight leak on one of the headers, i think the driver's side. i'm going to get some locking header bolts to fix that issue, but wanted to see if anyone had any other thoughts.

I've had all this done for quite some time (few thousand miles) and these codes just came up recently. if they had come on right after i had put the headers on i wouldn't have been that surprised, but i don't understand why they are coming on now. i just had the codes reset today at autozone and i'm waiting to see if they come back on.

thanks for the help, and sorry for the long post.

[96greenmachine]

Re: Running Lean, need help

bank 1 and 2 will probly need replacing other then that i dont know what to tell u bout the other stuff...i just replaced an 02 on the driver side manifold and that fixed the other 1's...code said it was runnin lean also. hope this helps bud

[5_spd_pewter_v6]

Re: Running Lean, need help

thanks for the info. since i had the codes reset yesterday they haven't come back on yet. if they come back on i think i might just replace the o2's and see what happens

[iGoRa]

Re: Running Lean, need help

P0151- pass side O2 sensor
P0171,P0174 - you are getting lean condition , after driving for awhile on hwy? oil in antifreeze?
P0446 - EVAP - check lines

the EGR into the intake just sucks regular air

EGR its a valve , when its working you are getting air into the intake instead of unburned fumes. This air is getting ito the intake pass MAF sensor , so you are getting more air without fuel, making your car go lean and you dont want that.

[Turbo V6 Camaro]

Re: Running Lean, need help

P0151 - Heated O2 sensor - circuit low voltage Bank 2 Sensor 1
(i don't really understand what that means, so please explain if you can)

you need a new sensor the hear is dea i would replace both so they are even

P0171 - bank 1 lean
P0174 - bank 2 lean

sound like you have a lot of exhaust leaks

[5_spd_pewter_v6]

Re: Running Lean, need help

P0151- pass side O2 sensor
P0171,P0174 - you are getting lean condition , after driving for awhile on hwy? oil in antifreeze?
P0446 - EVAP - check lines


EGR its a valve , when its working you are getting air into the intake instead of unburned fumes. This air is getting ito the intake pass MAF sensor , so you are getting more air without fuel, making your car go lean and you dont want that.

i don't understand how that is that much different than having the unburned fumes come in. that's still a volume of gas, just very dirty. also, when i got the headers i ordered the block off plate that attaches to the EGR attachment on the header from ZZP, and zoomer told me that i could do what i'm doing without having problems. also, it isn't something that happened immediately after i had the headers put on. it's been thousands of miles since then and i'm just now getting the code. could my car running lean have killed the O2's over time? also, if i block off the EGR into the intake, won't that throw a code?

[5_spd_pewter_v6]

Re: Running Lean, need help

you need a new sensor the hear is dea i would replace both so they are even


sound like you have a lot of exhaust leaks

i'm pretty sure that the only leak i have is on the dirver's side header. they broke one of the bolt when taking the old manifolds off, and i think there is just a small bit of the old bolt they didn't get, and it tends to loosen. when i have it tightened down it's fine for a while (no tapping sound) and then as time goes on and it loosens i get a tapping sound. i plan on getting locking header bolts to keep this from happening. other than that i don't think i have any leaks. i think i'm going to replace the o2's and see if that fixes it.

[iGoRa]

Re: Running Lean, need help

i don't understand how that is that much different than having the unburned fumes come in. that's still a volume of gas, just very dirty.

You can not see the difference between exhaust gas and fresh air? If there is no difference your entire exhaust would be directed right to the intake lol.

If you blocked it off the header, you would have to block it at the intake = !EGR. Blocking it at the intake will make your engine work back to normal and will throw EGR codes. To get rid of those codes you should by EGR sim form ZZP, zoomer should have mentioned that. Or delete them with tuning software.
So do yourself a favor, leave EGR alone if its not on your way and concentrate on exhaust leak. All broken bolts have to be removed and replaced. Tapping sound=manifold leak.