... so while I was waiting to get a response in my fuel trim thread in computer management...

i ran my FreeScan...

my left bank O2 sensor, .453, (pretty good in my book)
My right bank O2 sensor, .027... a bit lean, but the car smells really rich...

I was reading injuneer's tuning page
http://www.injuneer.com/ScanMast.html

Before I was concerned my O2 sensor was accurate, and what would cause such a dramatic lean condition...
however, in new light... it would suggest that the O2 sensor is failed?

I pressed the gas, and it increased into the .2xx area, but back at idle, it is below, valid voltage threshold?

 

is this the right replacement(what do i hear about wideband?)

Manufacturer: AC Delco
UPC-A: 707773397473
AFS75 - HTD Oxygen (POSN 1) OEM Sensor

D21 AFS75 - HTD Oxygen (POSN 1) OEM Sensor
O2 Sensor
OXYGEN SENSOR
[Heated Oxygen OEM Sensor]
IN EXHAUST MANIFOLD/CROSSOVER
Except Leaded fuel emis export (NM8)
Except Non-Heated O2 Sen (ABN)
Cross Reference for GM Part Number: 19178930

 

Are you saying that the left is sitting still at 0.453, and the right is sitting still at 0.027?

 

yep - not perfectly still... but yes

 

You have a bunch of engine-problem threads going on. I read a few, but didn't come across a description of what car you're talking about/what work has been done.

Is this the 95? Did you install an LT4 crate engine? If so, did the car work properly before the engine swap?

 

umm... All I know for sure, is the fuel runner is painted red...

the old owner told me several things, and i think he was lying or didnt know... he said he contacted one of the original owners, and was told:

Used to be a police intercepter it has 15x,xxx miles on it

but the engine came out of a 96 vette(was changed at 30k miles, about 30k miles ago, so 60k on the LT4), along with the trans, and the rear end... apparently he asked the guy why he didn't install some of the front suspension stuff, and that was the main problem with the donner vette.

I was under the impression if it was a vette LT4 it would say grand sport on throttle body (it doesnt)
the valve covers would say corvette (it doesnt)

so I am left to believe it is just a plain lt4 rebuild with a t56 and 3.42 rear end.
not sure, I got a box full of parts, various suspension things, and a bunch of head bolts... the guy i got the car from only had it a few months, and i think same story with the guy before him...

dont know how the car got to germany, all i know is the fuel runner is red, and it's got power above 2100 rpms...
he said something about the clutch, but i forget what brand he said, and it's also got magna-flow exhaust... with no cats...

 

When the O2 senosr is cold, disconnected, or not working, it will read ~450mV. That's the PCM reading its own bias voltage. I'd say unless you were checking it dead cold, the left bank sensor is either unhooked or deceased.

Right sensor may actually be reflecting a lean condition (was the AIR pump running? Do you even have an AIR pump?), or you have a voltage leak to ground. They shouldn't sit still IF the PCM is going into closed loop. But if your left O2 sensor is not working, its probably not going into closed loop - hence the O2 sensor readings are not cycling.

 

no air pump.

So, apparently my car never goes into closed loop (TPS low voltage) and according to my feescan only stays in BLM Cell 17 or 18(If I'm not mistaken one of those is WOT?)... however, when I originally wrote this thread, I was concerned with my right bank because the voltage was so low at idle(i didnt take the car out for a drive that time) I promise I was never at WOT since there is ice and snow on the pavement.

This drive, after I got to the gas station and filled up, I turned on my scanner, engine temp was 78* Celsius (where it remained for the rest of the drive)

the left O2 sensor, stays on .453 most of the time, every once in a while I see it flicker to .457, while the right side, stays low(.020v) at closed throttle, and at open throttle throttle is like .88x or above. at highway speeds, and I'm not accelerating the right bank is something like .15x... and if i take my foot off the petal it drops to .002 or so.

Edit: I just got 2 new sensors from RMS and am waiting to put them in, possibly getting headers soon. I don't want to ruin the brand new sensors by burning off the coating...

 

The PCM will not go into closed loop if the O2 sensors aren't working. One of yours (the left one) is not working.

No, one of those cells is not WOT. 18 is used in open loop when the engine is under load. Sometimes, in power enrichment mode, the PCM will switch to Cell 18, and lock the long terms and short terms at 128 (0%), but generally it will use cell 15 (if closed loop is enabled). 17 is used all the time when the engine is decellerating.

If you take your foot off the pedal, its normal for the O2 voltage to drop near "0"... the PCM cuts off fuel on decel.

Put the new O2 sensors in now. Keep your old sensors. Put them in LATER when you get cera-metallic COATED headers. You don't want to keep running with poor feedback to the PCM, waiting until later when you get headers to put the new sensors in.

 

thanks for the information, I'll put them in soon as i can crawl under there, I don't remember the O2 sensors being too terrible to replace, maybe bad angle, but... not too bad.

tried to get on my ramps today, but the ice in the parking lot didn't give me any traction. I'll try when the pavement is dry again. or if i ever get off early enough to go to the lifts.