case grounded vs. isolated ground O2 HELP!

[DURAtotheMAX]

Ok ive searched everywhere about the differences and specifics of these two different styles of O2 sensors.

This is dealing with the Gen III trucks/SUV's.

From the schematics, it looks like in 1999 they only used 4-wire case-grounded O2 sensors.

Then in 2000-2002 they came with either 4-wire case grounded or 4-wire isolated grounded O2 sensors.

Then in 2003, they switched to only "one" style O2...but I cant find anywhere if that "one" style they used from 03+ was case grounded or isolated ground???

Why are there the two different styles?

The engine is a 1999 4.8, so it has 4-wire case grounded O2's.

The PCM/tune is a 2004.

Basically my question is...does the PCM care what kind of O2 sensors its getting readings from?

Say for example the 03+ O2 sensors were all isolated ground...if I hook up my 1999 case grounded sensors to the 2004 PCM (that, in a factory application, is normally reading from isolated ground sensors), is that going to cause big problems???

Basically...id like to reuse these good 1999 4-wire case-grounded O2 sensors if possible with my 2004 PCM...that way I dont have to go out and buy 180 dollars worth of new O2 sensors for a "2004 4.8"

thanks
ben

[mr.prick]

In the schematics I have for the LS1 (516k) PCM
the case ground and isolated ground go to the same pin.
The "low signal" goes to the PCM and the ground goes to chassis.

[DURAtotheMAX]

ok I figured it out.

All 2003+ Gen III V8's used ISOLATED ground sensors.

So Ill need to buy new ISOLATED GROUND O2 sensors. But then that opens up a whole new can of worms. PLANAR VS. THIMBLE O2 sensors.

can you interchange them on Gen III PCM's? Does the PCM really care whether its looking at a planar vs the older thimble style O2 sensors?

Just a recap/over view of my setup:

1999 4.8 engine
2006 5.3 harness
2004 PCM, 4.8/manual tune.

In looking up parts on the advance auto website for various 2003-2006 4.8, 5.3 and 6.0 truck/SUV engines, and it shows both being used.

the two available O2 sensors are bosch universal 15730 (non-planar) and 15733 (planar) that go on the 4.8, 5.3, 6.0's. I used those numbers as a reference rather than comparing OEM numbers.

2007 4.8's used a non-planar 15730 upstream sensor and a planar 15733 downstream sensor. 2004 4.8's used 15733 planar sensors in both up and downstream.

4.8 Express vans used 15730 non-planar sensors on the right side up and downstream, but used 15733 planar sensors on the left side up and downstream.

WTF!!!

Then of course all the plugs are different too...BUT. I found one application that has the right OEM plug and is a lot cheaper for some reason. Its from a 2004 Express van, the up and downstream sensors on the RIGHT side, its a non-planar sensor, and its 40 bucks vs the LEFT side up/downstream planar sensors which are 90 bucks????

Supposedly planar sensors heat up faster??? So im guessing (seeing as express, silverado, tahoe, 4.8, 5.3, 6.0 have an endless hodgepodge of sensor configs depending on vehicle) it JUST has something to do with the configuration of the exhaust on the vehicle and NOT the actual calibration in the PCM.....in which case I would be fine using the 2004 4.8 Express van sensors on both sides upstream. Obviously im not using downstream O2's.

ben

[chevy052500hd]

on my s-10 2000 when I converted to the 1mb pcm I used the old o2 sensors that are case grounded. I am noticing however, while in cl, the a/f will spike to 13.5 while lean cruise is enabled, but without lean cruise it stays solid at 14.7. For all purposes I haven't noticed a difference on my truck, what are the benifits of a isolated ground sensor vs the old style? Faster response, less interference?

[chevy052500hd]

http://www.popularhotrodding.com/tech/0407phr_bosch_oxygen_sensor_tech/index.html

here is an article on those types of sensors for people that don't know like me LOL .... to anwser your question I don't think it matters, just will be less efficient. PCM won't care, I know it don't on my truck. I might swap them out to see if I pick up some gas mileage vs the old sensors, since this pcm I have is set up to have planars. I will report back.

[DURAtotheMAX]

yeah I read that earlier through a google search.

I bought the "right side upstream" sensors for a 2004 4.8 Express van. Bosch part number 15543. OEM fit, plug and play.

Reason I chose the 4.8 express van sensor specifically was because it was from a 2004 4.8, it fit my 2006 5.3 harness plugs, and it is $39.95. 4.8 silverado's use different connector styles that dont fit my 2006 5.3 harness, and are like 70 dollars......but both applications (4.8 silverados and 4.8 express vans) call for the same "universal fit" sensor.....so appearantly the 4.8 silverado O2 sensor connector or wire must be made of something *really special*, because the sensor itself is technically the same...or at least can be interchanged between the two.

I havent driven it yet, but im sure it will be fine. The guy at the auto parts store looked at my funny when I asked for "two right side upstream O2 sensors for a 2004 express". :D

ben