Hi, been awhile since I've been on but here is my question....I put shorty headers on my 5.0 in my 98 ranger. It's running good but in less than a year I've had to replace both front 02s....a friend suggested the increased flow from headers may be more than 02s can handle? Anyone have any thoughts or info on this

 

Whats failing on the O2's?
Are they going Lean/Rich, not switching, no connection, ect.....
Do both sides fail about the same time?

Leaded gas will kill them fairly quick.

Flow wouldn't be an issue, O2 sensor has a chemical that reacts with Oxygen and that creates a voltage, .1-.9 volts, so flow passed/thru the O2 wouldn't matter, oxygen molecules are sampled at any RPM or flow

O2s need to be above 650degF before they start to work, which is why they are Heated.
Earlier O2s didn't last long because they were not Heated, did you wire in the heaters?

High exhaust temps might effect O2s but I would be more worried about exhaust valves and pistons if exhaust temps were higher than 1,900degF for any length of time

 

Hi, the bank sensor went first, codes said lack of switch indicates lean and another code for slow response. Put in new 02 and within a week bank 2 went, same codes

 

How old were they?
And were they the same brand, motorcraft OEM(I think Bocsh) or 3rd party?

And was the engine fully warmed up at the time you got the code
O2 sensors are not used when engine is cold(because they would show lean and not switch) and computer only knows engine is cold from ETC sensor reading

O2 sensors need to be above 650degF to work

 

They were boch sensors, maybe 10 mths since they were installed by tune shop. Engine was warmed up at time of codes popping up

 

Check to see if the heaters are OK on both old ones, usually the two white wires, use OHM meter set at 200 ohms, should have a connection and lower OHMs like 12 or so, its a HEATER.
All heated O2 sensors will have 4 wires, two will be the same color wire, those are the heater wires, so could be black, white, grey, ??? but both the same color

If heater are not hooked up or burn out O2s won't last long

Some additives can short O2 and Cat life