93 5.7 cat delete o2 sensor light

[Nad_Yvalhosert]

Fair enough. Like I said, I haven't done it. Truth is when my cat rattled itself to death on my '94 5.7 it never set a code.

Richard

Because you don't have a downstream O2 sensor...

 

[someotherguy]

Because you don't have a downstream O2 sensor...

Neither does OP.

Richard

 

[Nad_Yvalhosert]

Neither does OP.

Richard

Now you're getting it!
(Insert thumbs up symbol here)

 

[someotherguy]

Now you're getting it!
(Insert thumbs up symbol here)

(insert eye roll symbol here)

 

[someotherguy]

^^^ I mean he's right, and it's my bad for posting without thinking the subject through as I'm only half-awake. This night shift stuff.. anyway, you think I'd know better after 20+ years of it. Though sometimes I think he enjoys following me around waiting to see if I trip up so he can giggle. It's OK.

Richard

 

[GoToGuy]

Just for the basics, first sensor upstream mixture data, second sensor , if equipped monitors cat health.
Just a side note: NTK/ NGK are high quality sensors, and have published a service bulletin describing early OBD1 having sensor problems , as newer current production sensors have very fast reaction time. This has caused some problems with OBD1 can't keep up and throws a code.
Apparently NTK has addressed this with sensors for OBD1 vehicles.
I'll repost the bulletin when I find it.

 

[FLGS400]

My 91 has an active O2 sensor and no cat. It runs great with no check engine light...

 

[GoToGuy]

Ok, that's normal. Having a functional O2 sensor is part of the fuel system. " Active " ? If not your truck would run like crap.

 

[someotherguy]

My 91 has an active O2 sensor and no cat. It runs great with no check engine light...

Point to the last several posts in this thread is an OBD I system doesn't have a post-cat O2 sensor to determine if the catalyst is doing its job; that's the one that will set the code if you don't have a cat, or your cat is bad.

The code you might get from a bad pre-cat O2 would be if the O2 itself was bad.

Richard

 

[ol-Betsy]

Lucky me no shops around have obd1 scanners that will give live readings of the sensor. I purchased an aldl cable to hook up to my laptop and monitor from there.

The point NTK sensor is definitely something I will look into. Could be an easy fix. I'll have to diagnose my current sensor first.

Would a post upstream sensor exhaust leak throw a code? I did find the slightest leak on top of the flange weld- a tough spot to squeeze a weld into with it on the truck. It's maybe a half inch in length where the flange is nearly tangent with the pipe. Very small. Nearly impossible to get a weld on without a flexible tip on a gun which I don't have. Note again, that before I even welded the flange, the exhaust was wide open after there, and I drove about 100mi with no codes thrown until after the exhaust was complete. Right after everything was installed.