getting 179 code and replaced o2 sensor on exhaust but i reset system and the same code comes back. is there two sensors? i have 93 f150 4.9 6 e40d. 2wd
short bed. any help ? Please!

 

"Code 179 (M) Fuel system was rich at part throttle Single, Right or Rear HO2S "

Remember, getting a code about a particular sensor does not necessarily mean the sensor itself is bad. As the code states, your engine is running too rich (as sensed by your O2 sensor). You need to find out why you're getting too much fuel to the system (unfortunatly I can't help you too much with the diagnosis, hopefully someone else can give you some pointers...)

 

Check the fuel pressure at the Shrader valve. Connect a high-pressure fuel pressure guage, cycle the key from off to on a couple of times. Leave it on. Don't start the engine. Pressure should be 40 to 60 PSI and should not bleed down more than 5 PSI in one minute.

If the fuel pressure is too high, the engine will run rich. Suspect the regulator or a pinched return line.

If the pressure bleeds down quickly, it may be a leaking injector, and (if so) the engine will run rich because of uncommanded fuel flowing into the engine.

If the static tests pass, start the engine and let it idle. Fuel pressure should drop 5 to 10 PSI. If it doesn't, check the vacuum line to the regulator. If it is bad, fix it. If it is good, consider replacing the regulator.

 

besure to check for a leaking pressure regulator. this is the common code found in this situation. a burst diaphram in the regulator will cause the fuel to flow through the vacuum hose dirrectly in the runner of the intake manifold. carefully remove the vacuum hose and check for the presence of gasoline. if any is found, replace the regulator..

Kurt