O2 ?

[C2500]

I’m new here and to TBI tuning so bare with me. After reading threw the O2 placement that EagleMark posted I think I need to move my O2.. I have a 94 c2500 pickup with a 383 in it that I just completed putting in the motor.
I have been dealing with ED for a chip and its on its way back to him for adjustments..I noticed that when you shut down and restart it goes in open loop and sits there till the O2 starts switching or if you hold the rpm up it goes in closed loop quicker..
I replaced the Y-pipe with a after market and now notice that the O2 bung seems to be longer and not much of the sensor is in the flow path so I was thinking if shaving down the bung to get it in there farther but now thinking of placing it closer to the collector.. I have a set of stainless shorties that bolt up to the original Y-pipe as the stock manifolds kept on cracking (Chinese junk aftermarket) so these have been good so far..But its only has a bung in the left collector is that an issue? I could tig in another in the right side and swap side to side any thoughts? Also I’m going to need a harness extension to relocate it..
After reading Eagle Marks post it should heat it up quicker and go in closed loop quicker right??
Here’s a pic of where the O2 is just before the cat..

[dave w]

I would agree, the current O2 bung should be shorter.

The basic theory of operation for an O2 sensor: needs to be hot to work. There were some factory 4.3 V6 applications that used a 3 wire heated O2, most likely because the exhaust did not get a single wire hot enough to work properly in all driving conditions.

Maybe convert you O2 to a 3 wire? https://www.ebay.com/itm/3-Wire-Heat...4383.l4275.c10 and https://www.ebay.com/itm/ACDelco-AFS...lUkUyV&vxp=mtr

dave w

[C2500]

Dave it is a 3 wire I should have posted that sorry. But I would still think it should work better if its up stream closer to the engine.

[Terminal_Crazy]

The LT1 $EE PCM has 3 time delay setting and some temp settings that have to pass before going into CL.
As I understand it this is to stop pollution of the BLM tables with flakey data until idle settles down.
I presume your pcm does something similar.

HTH
Mitch

[lionelhutz]

That's the stock location, right? If yes, then it should be fine there. Just shorten that bung so the whole sensor nose is in the pipe. The bung should just be long enough to hold the threads.

Is ED from Harris Performance or TBI Chips? If yes, good luck with that one....

[C2500]

Yes that’s stock location...
No its Ed from fast chips...I have heard to stay away from Harris performance..

[C2500]

Yes that’s stock location...
No its Ed from fast chips...I have heard to stay away from Harris performance..

Well let me retract that this is an aftermarket front pipe with a converter and I’m not sure if its in the same location as original but I do know that the O2 wires are a little taught..
Any one have a pic of an original front pipe for a 94 with a 350 or even a 305 I would think be the same...