Aight. Went to install a set on my friends truck (well, actually just one). It's a 1999 Ford F-150 with the 5.4L. She hollowed out her cats and wanted to get rid of the check engine light. After a crap load of diagnostic tests to find the power, ground, and signal wire, we finally got it hooked up. So we though. The truck definately runs better now, but the check engine light is still on. I put the O2 simulator on the rear OS sensors cause that's where I've always been told to put them. Should I move them to the front? Anyone have a wiring diagram of the Ford O2 sensors? There are 2 white wires, 1 gray wire, and 1 black wire. The black is ground, one of the white wires is power, and we think/thought that the grey was a signal wire. Here's the site we bought them from and the instructions we used. Any help would be greatly appreciated. Thanks a lot yall.

 

You broke it

 

The vehicle will need some cycles from cold start to operating temp without the signal telling it hte cat is dead before it will reset the check engine light- or somebody with a code reader can reset them too. (Don't tell them you have sims, just that you replaced the cat.)

AlpineRAM

 

We unplugged the battery while we were installing the thing.

 

Why are you running the sims? O2 sensors have nothing to do with the cats other than providing them with an appropriate oxy level to burn the pollution; but I would think the ECM would still like the feedback signal to provide good performance.

There are many folks running off-road h-pipes on fast street cars with O2 sensors. You might have weld on a mounting boss for them though.

BB, how do the sims work? How do they know what O2 level to simulate?

 

bulabula


my 01 dodge gasser had 2 o2 sensors one before and one after the cat

the one before the cat was for the computer to run the engine on ..........

the one after the cat was for the OBDII system just to check and see that the cat worked properly ........... if it didn't get a proper signal from the second one for some reason (such as removing or hogging out the cat) it set a check engine light

so the 02 fooler is needed to tell the computer the cat works properly.

Blue I believe the check engine light should go out after 4 or 5 "trips" if the computer gets no more codes

 

Make sure the sims are for dual O2 configurations.

The ECU as part of it's diagnostics runs a set of tests on the cat. Watching the response of the two O2 sensors to determine if it's functioning properly. I can dig up detail on how Ford does this if you're really interested.

The wires are:

white and white - O2 heater, no polarity. One will be + the other -, don't power the sim from this unless they tell you to. Some vehicles, not sure about the Ford, control their heaters to help maintain a constant temp.
black - ground
gray - signal

 

Thanks, Dodgeram.

 

Thanks stevenknapp. This particular O2 sim is set up for a dual config.