I recently installed LT headers on my 85' 305 TPI I replaced the old stock 02 sensor with a newer Bosch one (non-heated) It does idle better and seems to even run cooler with slightly better MPG, However now every time I floor it I get a check engine light, if driven normal or if I press the gas gradually and not to abruptly the light wont come on, the 02 sensor is located on the collector pipe of the driver side header, would you all suggest I try a heated type sensor? I'm not sure if it is needed since it is not on the y-pipe but what do I know??.. Any input fellas???

 

Yes, YOU WILL NEED THE HEATED 1.

<-"been their done that"

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OK! well glad to have cleared that up I ordered a 3 wire adapter and an AC Delco heated 02 #ASF74 , would anyone be so kind as to tell me where to wire the positive on this 3 wire adapter? I read the fuel pump wire would be the best bet, however I don't know where that is

 

Just find a switched 12 volt wire.

 

I was looking at a fuel pump wire diagram, would that " 12 volt wire" be the light blue wire or the red one ??

Diagram Here>>> http://berlinetta.info/media/shopman...lPump85TPI.jpg

 

EGR or smog PNK/BLK are on the emissions fuse. Do NOT tap into the fuel pump relay wiring

 

I use the IGN circuit prong under the dash (in the fuse box) come off that, into a blade type fuse and then run out to the sensor, which I have it hooked to the factory wiring with the proper connector/adapter. So if i'm on the road and cant find the fox body mustang 3 wire 02 sensor I can use a gm single wire, plug it in and get it home.