So I've seen these sensors on 5th gen ludes mounted on the exterior side of oil pump and I thought they always had 2 input sensors. Is this true ? .. Do any 'ludes have 1 input sensor at that location ?
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OBD2 USDM h22's have the CKP and TDC sensor located on the oil pump housing

 

How about the OBD2 JDM h22's ?

 

the info i have collected says they are all located in the distributor.

 

This is the item in question. It's from a Prelude, but which year(s) ?

 

ive never seen that before, but that is the CKP sensor minus the TDC sensor. Originally when i saw that i thought maybe the TDC sensor had been removed for some reason but the connector is only two pins so that kinda eliminates that thought. Maybe from the JDM "OBD2" 96 models. The red headed preludes

 

Not a Civic/Integra CKF perhaps?

OBD2 directives required sensing misfires, so you got CKP/TDC both on the crankshaft for OBD2 US Preludes.

Where those directives didn't apply (everywhere else) they were kept in the distributor with CYP.