Oxygen sensor location
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Oxygen sensor location
I'm working on a buddies 88' F350 crew 4X He had headders installed and need to find out if the O2 sensor is in 1 pipe reading 4 cyl or 2 reading 8 cyl it has a 460 with auto and it has dual pipes into the cat and single out any info would be great ...........
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On an 88 it dosen't matter if the O2 is reading from 4 or 8 cylinders, it'll work either way. On the later models the PCM uses one O2 on each bank, and another after the cat, but I'm pretty sure an 88 would use only one.
If it indeed has only one O2 sensor and dual pipes going into the cat, then the sensor can be located on either bank, downstream of where the header pipes collect. Don't mount it after the cat, it'll run way too rich.
If it indeed has only one O2 sensor and dual pipes going into the cat, then the sensor can be located on either bank, downstream of where the header pipes collect. Don't mount it after the cat, it'll run way too rich.
Last edited by thelonerangerxlt; Aug 12, 2004 at 09:32 AM.
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Thanks... But it seems strange that it does'nt matter if it reading 4 or 8 you would think that the the oxygen levels would be different.. It has a hi idel with some miss but you rev it up and no miss ........
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Well, the O2 sensor is reading the percentage of burnt gases rather than the volume. Under normal conditions the readings will be the same, whether taken from one bank of cylinders or both. If there's a misfire or vacuum leak on one bank, then the location of the O2 would matter, since the O2 would pick up a rich (or lean) condition if it was reading from both banks. That's why the later models had a sensor on each bank; to make it easier for the ECM to isolate a problem to the specific bank.
If the truck has a high idle that the IAC can't correct for, I'd suspect an intake manifold vacuum leak. A vacuum leak could also cause a lean misfire that would smooth out as rpm increases. An open EGR valve at idle will also cause a miss. Hope this helps.
If the truck has a high idle that the IAC can't correct for, I'd suspect an intake manifold vacuum leak. A vacuum leak could also cause a lean misfire that would smooth out as rpm increases. An open EGR valve at idle will also cause a miss. Hope this helps.
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