Pre cat O2 sensor question (1 Viewer)

[Boz_10]

Finally got my catalytic converter installed after someone cut it out. I had a friend install/weld some exhaust piping along with Magnaflow single cat 2.5" in place where the thieves cut the stock one out.
The post cat O2 sensor is in place, but the pre cat O2 sensor is missing. My friend did not know there is a pre cat O2 sensor so he did not make a hole for pre cat O2 to be installed in. Basically, now I only have post cat O2 sensor.

My question is, in my case ('97 FZJ80 w/~ 155K miles), of what importance is the pre cat O2 sensor? Is it all right to drive without one? How hard would it be to drill a hole to place a pre cat O2 sensor in?

I can reset the ECU, but am I doing more harm by not having the correct oxygen/fuel mixture by not having the pre cat O2 sensor? Is my timing, power, or mpg compromised?

Any advice is helpful!!

Thanks

PS: I searched, but got limited results back.

 

[Firedog]

I don't know about what damage it could do, but i would imagine that it will effect the mileage, power and possibly the longivity of your new cat.
It's easy enough to replace the bung, just order one from Slee, cut a hole for it and weld it in place (or any muffler shop should be able to do it for you.)

 

[Beowulf]

My question is, in my case ('97 FZJ80 w/~ 155K miles), of what importance is the pre cat O2 sensor? Is it all right to drive without one? How hard would it be to drill a hole to place a pre cat O2 sensor in?

Your truck is OBD-II and both O2 sensors are important. Very important. You will be in a limp-home mode without the O2 sensor so your truck is not running optimal. The timing is retarded, the fuel mapping reverts to a base map. Your power will be down. Your MIL will stay on. You'll never pass emissions.

You should follow firedog's advice and install a bung and O2 sensor.

-B-

 

[Boz_10]

...thanks for the quick reply!!

Sorry for the ignorance, but what is a "bung"?

 

[Beowulf]

From the Slee web site:

http://sleeoffroad.com/products/products_drivetrain_driveshaft.htm

-B-

 

[nicholas]

I agree, go with the slee bung and an OEM sensor from CDan. Mine had a generic O2 sensor in the front that was worthless. I got horrible gas mileage and I probably added a lot of carbon deposits in my engine as well as possibly shortened my cat's life.