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How many O2 sensors am I supposed to have?

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Old 05-17-2010, 03:58 AM
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Default How many O2 sensors am I supposed to have?

'96 Ram 1500 4x4 with the 318 and 5 speed. PO modified the exhaust system, putting on a flowmaster, and may have changed the cat. The cat currently is a dual inlet, single outlet, with an O2 sensor installed in the front of the cat between the inlets. There's another O2 sensor ziptied to the driver's side frame rail, right where the frame flattens out near the trans (flattens meaning where the frame is curved coming from the front suspension area, the frame isn't actually bent or smashed flat anywhere). The check engine light was on when I got the truck, the only code it's showing (using a scanner) is Bank 1, position 2 O2 sensor. PO told me the sensor was there, it was the post cat sensor, and because of the exhaust mods, there's no place to install it (I'm intending on welding in another bung behind the cat shortly). Given the code is bank 1, pos 2, that makes sense.

However, when I was looking at Hughes website for the plenum gasket upgrade, their site shows both a left front, and right front O2 sensor for the '96 Ram. Am I supposed to have two pre-cat O2 sensors? Or is possibly a factory option for true dual exhaust, and I just have a single exhaust truck?
 
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Old 05-17-2010, 06:31 AM
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Cal trucks had 4 one in each bank one pre cay pne post cat. All other trucks had one pre cat one post cat.
 
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Old 05-17-2010, 09:00 AM
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To translate what Max said into more readable lingo...

California trucks had four sensors, as they also had "pre-catalytic converters" in addition to the normal catalytic converter. The other 49 states only had the standard 2 oxygen sensors, one pre-cat (1999 and earlier, it was in the cat itself, 2000-2001 it was before the cat), one post-cat.

When ordering sensors (if you end up ordering them), and you are given two options for the pre-cat sensor or the post-cat sensor, make sure that the plugs are the same as your old one, and if they are, get the one with the longest wire length.
 
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Old 05-17-2010, 12:47 PM
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im also about to have this problem, so if i just mount my 02 sensors back in my pipe i should be good, im going to get rid of my cat until i cant get a highflow. im also going to be getting the custom tune from hemifever so i dont want the o2s to screw with my a/f ratio
 
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Old 05-17-2010, 01:04 PM
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The primary O2 is what the computer uses to read the A/F ratio. You really do want that one in there.

Tunes are mostly for tweaking open loop operation, and massaging timing tables so that you get better power throughout the RPM range. (and to fix some of the factory silliness.) Can do an awful lot with the right software.
 
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Old 05-17-2010, 01:46 PM
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Originally Posted by jasonw
To translate what Max said into more readable lingo...

California trucks had four sensors, as they also had "pre-catalytic converters" in addition to the normal catalytic converter. The other 49 states only had the standard 2 oxygen sensors, one pre-cat (1999 and earlier, it was in the cat itself, 2000-2001 it was before the cat), one post-cat.

When ordering sensors (if you end up ordering them), and you are given two options for the pre-cat sensor or the post-cat sensor, make sure that the plugs are the same as your old one, and if they are, get the one with the longest wire length.
Thank you Jason I didn't have my glasses on and it was right before I was leaving for work.
 
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Old 05-17-2010, 01:58 PM
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Originally Posted by dodge15004x45.9
Thank you Jason I didn't have my glasses on and it was right before I was leaving for work.

Glasses??
 
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Old 05-17-2010, 02:29 PM
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that sounds a lot like the truck that i junked in Seaside CA. I believe the junkyard was salinas based.

I had a post cat O2 sensor simulator bolted to the frame rail. But I took the PCM, MSD, injectors, TB and headers from the truck before I junked it.

It was not a cali emissions truck to begin with. BUT if it was my truck, then they might have put a cali PCM in there,

I had a gutted cat, and sidepipes. it was also a green truck.

If you want the Performance PCM (federal emissions, not california) I still have it, if you want to buy it.

100 bucks plus 12 shipping and its yours. A lot better than 300 from the dealership. I had a 4x4 5.2 auto trans.

--Dan
 
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Old 05-17-2010, 02:32 PM
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Old 05-17-2010, 02:38 PM
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If there is a burn mark on the drivers headrest, than that it my truck. THey may have repainted it because of the paint peeling onj the hood due to a fire in the engine compartment.

It sounds eerily familiar. THe truck was operational when I junked it, but I was in a rush to move, and it was not a cali emissions passable car. So I could not sell it without a hefty fine.

I am guessing that if it is the truck, then the check engine light is because it is supposed to be reading more 02 sensors because they might have slapped in a Cali Flashed PCM. California and NY have their own emissions, different than the federal.

--Dan
 


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