Effects of different 02 sensors

**sdkcg** · 01-08-2007, 02:05 AM

Trying to diagnose a pig rich and stalling condition on a newly installed 96 LT1 (OBD-II) in a 68 camaro.

At idle, the emissions are pretty bad...gasoline smell in whatever you are wearing.

I hooked up autotap and found a pretty constant 45 mV on B1S1 and very lazy 375-425 mV on B2S1.

When I brake for a light or stop sign, the car typically stalls. Power brake
application is forcing a very rich condition, maybe? I need to do some more runs..

I pulled the front O2 sensors (no rears) and found two different model sensors.
Left was 4E31 (unknown brand, very small diameter), right was AC AFS 138.

I was hoping to swap in two LS1 O2's to see if that made a difference, but the connectors were a different config

Would the two different 02 sensors make a difference and explain some of the above?
I will probably just order two new O2s and call it a day...

Programming by PCMForLess. No codes detected, but the programming is basic air/fuel/spark lot has been programmed out.
I need to get 'Edit soon, but that is another story

thanks
Scott

**jasonisdn** · 01-09-2007, 05:51 PM

you running the 2 sims forthe rear 02 sensors? my 96 had a different 02sensor for the rear and front like normal but when we went to buy new front ones the part numbers didnt match up at the dealership, advance or auto zone. take both in and replace both with bosh sensors. 1996-1997 front heated oxygen sensor
AC-Delco # AFS75
1996-1997 rear heated oxygen sensor
AC-Delco # AFS97
if you can get it to pull a code try this
http://shbox.com/1/Dtcs.htm

Originally Posted by sdkcg

Trying to diagnose a pig rich and stalling condition on a newly installed 96 LT1 (OBD-II) in a 68 camaro.

At idle, the emissions are pretty bad...gasoline smell in whatever you are wearing.

I hooked up autotap and found a pretty constant 45 mV on B1S1 and very lazy 375-425 mV on B2S1.

When I brake for a light or stop sign, the car typically stalls. Power brake
application is forcing a very rich condition, maybe? I need to do some more runs..

I pulled the front O2 sensors (no rears) and found two different model sensors.
Left was 4E31 (unknown brand, very small diameter), right was AC AFS 138.

I was hoping to swap in two LS1 O2's to see if that made a difference, but the connectors were a different config

Would the two different 02 sensors make a difference and explain some of the above?
I will probably just order two new O2s and call it a day...

Programming by PCMForLess. No codes detected, but the programming is basic air/fuel/spark lot has been programmed out.
I need to get 'Edit soon, but that is another story

thanks
Scott

**sdkcg** · 01-10-2007, 03:42 AM

Hey Jason...
Thanks for the feedback...

Someone also suggested checking for vac leaks..I did have the intake manifold off the car, and throttle body off...maybe a bad replacement gasket? Gotta look into that as well..

ohh, Not running any rears...the LT1 is installed in a 68 camaro..no cats/no emission concerns

Scott

**jasonisdn** · 01-10-2007, 08:58 AM

Originally Posted by sdkcg

Hey Jason...
Thanks for the feedback...

Someone also suggested checking for vac leaks..I did have the intake manifold off the car, and throttle body off...maybe a bad replacement gasket? Gotta look into that as well..

ohh, Not running any rears...the LT1 is installed in a 68 camaro..no cats/no emission concerns

Scott

unless you have a program that will knock them out of the computer , the factory ecm will still be looking for them. they can effect the air fuel ratio. i run the sims on mine, somehow it keeps passing emissions though

are the hoses you have the factory hoses ? if so you might have some dry rot going on. good luck man.

**Red on Red WS6** · 01-10-2007, 11:41 PM

Originally Posted by sdkcg

Trying to diagnose a pig rich and stalling condition on a newly installed 96 LT1 (OBD-II) in a 68 camaro.

At idle, the emissions are pretty bad...gasoline smell in whatever you are wearing.

I hooked up autotap and found a pretty constant 45 mV on B1S1 and very lazy 375-425 mV on B2S1.

When I brake for a light or stop sign, the car typically stalls. Power brake
application is forcing a very rich condition, maybe? I need to do some more runs..

I pulled the front O2 sensors (no rears) and found two different model sensors.
Left was 4E31 (unknown brand, very small diameter), right was AC AFS 138.

I was hoping to swap in two LS1 O2's to see if that made a difference, but the connectors were a different config

Would the two different 02 sensors make a difference and explain some of the above?
I will probably just order two new O2s and call it a day...

Programming by PCMForLess. No codes detected, but the programming is basic air/fuel/spark lot has been programmed out.
I need to get 'Edit soon, but that is another story

thanks
Scott

Send me the auto tap log or change it to csv. format. You need to get the right O2 sensors in there. Only use the AC Delco O2 sensors. Also as for the rear O2's they don't do jack for A/F ratio, they are only used to monitor the cats. Are you getting an SES light?