O2 Sensor Location

[ososbob]

Need some help from the members. I have a 1980 Fiat with a VAS header. I have two problems, one an oil leak near the header/cam housing. I believe it's just the header bolts seeping oil, I'm going to pull those RTV them and put back in. Problem number two: the VAS header has the O2 sensors mounted a few inches from the head on the cylinder #2 pipe. In my head the ideal location would be where all of the header pipes collect into one exhaust pipe. I can pulg the hole and move the O2 Sensor, would this be beneficial or a waste of time. The engine does run very solid except at idle its a bit rough, nothing significant but it still not as smooth as I would like. The engine was rebuilt by me a few years ago and I went through everything.

[wizard124]

My understanding is the O2 sensor is not hot enough at idle to provide the closed loop feedback to the ECU. If you have a rough idle, go thru all the other components first, vacuum leaks, timing, etc.

Its current location is only adjusting mixture based solely upon the readings from #2 rather than the average of all four. If performance is satisfactory, than I would leave well enough alone.

[bradartigue]

O2 sensor won't make the car run rough. Whatever is making it run rough you need to address b/c it will just burn up more O2 sensors. They're fragile and don't like bad running conditions. The sensor makes minute adjustments that optimize the fuel mixture, but they don't govern operation to the extent that the car will run all that poorly.

Interesting to place the sensor in the #2 pipe (or any pipe right off the head)...L-Jet delivers identical amounts of fuel per cylinder so the mixture is always, in theory, identical per pipe. It will warm up faster there, but its a much hotter spot than where FIAT put it (beneath the collector, in front of the catalytic convertor). If it were my car I'd put it under the collector in the main pipe, as close to the collection point as I can.

[ososbob]

Thanks for the advice, after careful thought and the appearance moving the 02 sensor will likely have no real advantage I'm electing to leave it where it is. The mechanic who smogs my car says I have it running extremely well. I Just a bit of a perfectionists when it comes to engine performance. I do believe one of my intake valve clearance is a bit off, I might start with that.

[So Cal Mark]

it's pretty obvious the header manufacturer has no clue what they are doing. I'd move the O2 sensor if it were me

[bradartigue]

Thanks for the advice, after careful thought and the appearance moving the 02 sensor will likely have no real advantage I'm electing to leave it where it is. The mechanic who smogs my car says I have it running extremely well. I Just a bit of a perfectionists when it comes to engine performance. I do believe one of my intake valve clearance is a bit off, I might start with that.

Oh I disagree. It would make no difference if engine conditions per cylinder were identical at all times...but they are not. I would move it to under the collector, we're talking about maybe $25 for someone to weld in a fitting?

This has little to do with smog; the Spider engine will pass smog inspection without the O2 sensor working.