O2 sensor problems

[zachary A makoff]

my 98 k1500 with a 5.7 came factory with true duals and I installed the jegs cat delete y pipe and new upstream o2 sensors and 1 downstream.I didn't do the 2 downstream as it was after the pipe and stuck. After I finish I am now having a check engine light with the codes P0134 and P0154 which are no activity for the upstream O2 sensors. I hooked up my scan tool and checked the voltages and they are staying at 0.45 the ones that I replaced. the one that I left is fluctuating from .03-07. Any ideas?

 

[zachary A makoff]

I purchased a set of upstream and downstream from carparts.com and thought maybe the upstream are bad so ordered another set of upstream from them and it is still doing it.

 

[Caman96]

I purchased a set of upstream and downstream from carparts.com and thought maybe the upstream are bad so ordered another set of upstream from them and it is still doing it.

So they are house brand o2 sensors?

 

[zachary A makoff]

I believe so, there drive wire brand.

 

[Caman96]

There are many parts I’d substitute with other brands but sensors I’d stick with Acdelco only. I have no experience with parts you bought, but I can’t tell how many times I’ve read where people end up with Acdelco resolving the issue.

 

[zachary A makoff]

alright sounds good Ill start with that

 

[df2x4]

^ X2. For any sensors on these trucks I'd stick to GM OEM/ACDelco whenever possible.

I'd also check your wiring and connectors to make sure that nothing got pinched or damaged when you did the exhaust work.

 

[Schurkey]

I'd also check your wiring and connectors to make sure that nothing got pinched or damaged when you did the exhaust work.

^^ X2

Are they the correct sensors? Plugged right into the vehicle wire harness without trouble? Wires not melted from contact with the exhaust pipes?

 

[GoToGuy]

If you don't have catalytic converters installed, you will have a check engine warning. On a O2 sensor system with upstream and down stream sensors. The upstream is watching the mixture, like most have since beginning. The down stream , or after cat sensor is monitoring cat health. Tougher pollution laws. If delete the cats , they don't pass health check, constantly thinks cats are no good. Have you retuned pcm for removed cats?
Some vehicles are picky about brand. Some aftermarket are crap. I use NGK/ NTK they work.

 

[tinfoil_hat]

If you don't have catalytic converters installed, you will have a check engine warning....

Exactly my thought. You can't do a cat delete with stock sensors.
There is a cheap possible workaround... Go on Amazon or ebay and buy some "sparkplug defouler" spacers. Install these between the downstream sensors and the pipe. This moves the sensor element far enough out of the exhaust stream to fool the computer.
It's always a good practice to use ACDelco electronics in these vehicles, though I have had good luck with Bosch sensors for years.
Don't let anything touch the sensor element and contaminate it before install.