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CITYBOY
November 24th, 2004, 13:46
On a 2000 XJ, how many O2 sensors are there? It looks like there are 2 on the exhaust manifold, and one on the down pipe, I would like to replace them, but only want to go the parts store once, any help would be appreciated!

5-90
November 24th, 2004, 13:56
Two on the exhaust manifold? I seem to recall there should only be one there - near the collector. The other one should be just aft of the catalytic convertor.

Typically, an inline engine will only have one in the exhaust manifold - if you've got a "V" engine (V6, V8) you'll have one in EACH manifold, and then one after EACH catalytic converter (one if there's one, two if there's two,) but there's not reason for you to have more than two. You may want to have another look to be sure. Also, if you have some sort of aftermarket fuel/air ratio gage installed, that could account for the extra in the manifold...

5-90

jldiaz
November 24th, 2004, 16:36
California emissions?

5-90
November 24th, 2004, 17:17
California emissions?

Shoudn't matter by then - the main era for major differences was 1966-1972. CA Emissions started in 1966, with Federal programmes in place in 1968, and they played catchup mostly until 1972, but finally meshed in 1974 with the mandating of electronic ignition. The principal differnces after that is not in equipment, but in engine tuning and allowable tailpipe emissions. The technology between "49-States" and "California" is otherwise basically the same.

5-90

Ron Hyslop
November 24th, 2004, 19:41
My 01xj 4.0L has four o2 sensors, two in front of the pre-cats and two aft of the pre-cats.

5-90
November 24th, 2004, 20:22
My 01xj 4.0L has four o2 sensors, two in front of the pre-cats and two aft of the pre-cats.

?!?

How's that work - did the exhaust get split? That's odd, even for Daimler-Benz...

5-90

jldiaz
November 25th, 2004, 04:27
'00 and '01 4.0Ls have two exhaust manifolds. Each serves three cylinders: fore and aft.
In a CA-emissions equipped XJ, there is at least one O2 sensor per manifold, probably two.

CITYBOY
November 25th, 2004, 05:15
?!?

How's that work - did the exhaust get split? That's odd, even for Daimler-Benz...

5-90

manifold gets split into two, three cyl per side, one o2 sensor per side of manifold at the pre cats, then one before the cat and one after the cat, thanks for the info everyone!

JoBo
November 25th, 2004, 05:43
manifold gets split into two, three cyl per side, one o2 sensor per side of manifold at the pre cats, then one before the cat and one after the cat, thanks for the info everyone!


Split manifolds, or two, is how they finally solved the cracking manifold problem!

JoBo