Originally posted by Rogerm60:
If the signal from the O2 to the ECM is open or shorted to ground, that O2 will read lean. If it reads lean, more fuel is mistakenly pumped in . Same is true of a bad O2, but since it's new I doubt it's bad.


What A/F ratio gauge??? Where is it hooked in???

Cheap A/F guages use a normal O2 sensor for data. These can be very inaccurate if the mixture is out of range. Wideband O2's (also called a UEGO, or Universal Exhaust Gas Oxygen sensor) stay accurate but are very expensive.


Any high impedance meter will do for an operational check. An osciliscope is needed only to find quirks in a working system.

The O2 should be getting 12vdc to the heater, usually on the two white wires.

The signal to the ECM would be black for + and grey for - .
This signal bounces around with an average of about 0.45 vdc. If the output is zero, there is probably a wiring fault.



I am going to check those wires that you mentioned and check the voltage on them . The a'f gauge i have is from autometer and it is hooked up to the front o2 which is the one i am having a problem with. it does give me some idea whats going on.



Now i have talked to my mechanic and he also mentioned maybe the fuel regulator? what do you guys think about that? Becasue when i get up to 5000 rpm the car feels maxed out and doesn't have any more power......


But today while messing with my car i discovered something. Mechainc told me to check the spark plugs. Now he is the interesting part. The front 3 plugs near the radiator were motorcraft and the tips were ashy color looking.

Now the 3 rear cylinders near the fire wall, i have ngk iridium plugs and when i pulled them out the tips were extremly white and you could tell the difference between the front 3 and rear 3. What do you guys think about this discovery? please help

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