by "CodyVella" (codyvella)
Published 02/22/2017 at 23:49
by "CodyVella" (codyvella)
Published 02/22/2017 at 23:49
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STARS: 1
So the passenger side exhaust manifold on my Xterra cracked, and I popped it off to fix it. In doing so, I had to remove the primary catalytic converter (The damn truck has 4). After I popped it off, I realized the damn thing was hollow! So out of curiosity I also popped the driver side off. Hollow! There’s nothing inside them at all! The best part is, the downstream o2 sensor reads the emissions after this cat, and before the secondary cats. So in theory, the truck should throw a check engine light and a code, but it doesn’t. The OBD2 computer is literally saying all is cool. My truck passed an emissions test like this. I have no idea how, but it did. I also checked for o2 simulators, and there are none. I have no idea what this truck is doing anymore.
"DipodomysDeserti" (dipodomysdeserti)
02/23/2017 at 00:28, STARS: 0
Did you buy the truck used? Most likely the PO programmed the ECU to ignore the codes. Emissions tests for OBDII cars only checks for engine codes.
"CodyVella" (codyvella)
02/23/2017 at 00:34, STARS: 2
I bought it used two years ago with 250,000kms, and it now has 349,000kms. After some lengthy poking around, it seems a few others have had their pre-cats blow out and completely dissolve into nothing without throwing any codes. Apparently this only happens on the supercharged models. I’ll have to check with my code reader and see what the monitor on it says the sensors are reading, but apparently downstream sensors always show the same reading. Like the ECU on the SC model was pre-programmed to ignore them from the factory.
"Tristan" (casselts)
02/23/2017 at 01:00, STARS: 0
My ‘97 XJ had an aftermarket cat with a built in O2 bung when I bought it. The thing was welded on backwards, however, so the downstream O2 sensor was located just in front of the cat. Never threw a code.
"Mustafaluigi" (mustafaluigi)
02/23/2017 at 09:03, STARS: 0
Those studs tho...
"brianbrannon" (brianbrannon)
02/23/2017 at 12:18, STARS: 0
Some of those trucks had empty pre cats from the factory. The primary O2 sensor doesn’t monitor cat efficiency anyway so it’s most likely not as it should. If the pre cat had disintegrated it would probably have clogged the main cat or destroyed your engine by being sucked back in