Heated O2 sensor P/N

[AudioMaster]

I was curious if anyone had the Part number for a heated o2 sensor. I have an 87 with headers and I welded the bung and installed the sensor at the collector. I have been told that having a heated sensor is better than the stock one wire.

 

[camiswelding]

my truck is an 89 v3500.... told my parts man I wanted to go three wire... we looked at a later chevy..mid 90s.... they were the same for alot of years... fitting was 1/2 pipe if I recall

it was a bosch... works slick easy install (CFM TECH page)

didnt save the part number..sorry... but they are easy to find

cam

 

[dyeager535]

IIRC AFS-74 AC Delco.

Bosch has had problems with their O2 sensors for awhile, head over to thirdgen.org or diy-efi.org's archives to see for yourself. Enough people have had problems with them to justify to me, getting the Delco stuff.

 

[XHitman396]

why would it matter that much, the fuel trims are on a preset computer mixture until the O2 heats up, which isn't very long.. i dont understand the significance i guess is what im saying...

 

[dyeager535]

Actually, the O2 is on a timer, at least for OBD1 setups. It is a fairly long time. With the heated O2, if the engine can stand the leaner 14.7:1 (ideal) mix of closed loop, you can modify the timer for the O2 so that the ECM goes closed loop much faster. IIRC, engine temp needs to be around 120-140* before one of the criteria for closed loop is met, along with the timer.

Short of all that, the reason MOST go with the heated O2 on an otherwise completely stock setup, is that when swapping to headers, the O2 sensor either doesn't heat up enough to go closed loop, or only heats up when the engine is under load. That means at idle, after cruising for a bit, your engine will "drop out" of closed loop. This would really hurt you, for instance, at an emissions test.

 

[MarcS]

A heated sensor is much more stable and accurate than one that is heated by the exhaust.
Like dyeager535 said, it can drop in and out with exhaust temp changes and cause the computer not to make the best air/fuel changes.