QuestionQUESTION: Hi Nigel,
I just purchased the code reader today and am learning how to use it. There
were many codes in the computer. In this order. P0174, P0171, P0455,
P1300, P0304, P0300, P0734 and P306. I reset the computer on the car and
the first codes that came up were P304 and P300. Could all the misfiring be
due to a faulty Mass airflow sensor? Thanks again!
ANSWER: It appears to me that you have all the codes that I predicted in my last answer, indicating multiple misfires (cylinders 4 & 6) and an air mass meter failure. The best course of action for the misfires is to replace all coils, plugs and plug leads as you do not want to have to keep going back in to replace each separately. Obviously, you also should replace the air flow meter.
The P0455 fault is an evaporative fault, which usually indicates that you have not fully closed the gas cap. Close it and re-set it.
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QUESTION: Hi Nigel,
Well, I replaced the 2 plugs that were misfiring. 4&6 And put a new tank of
gas in it and drove for about 15 miles. It was like a new car after about 3
miles. I'm guessing it was the MAF sensor and it took a few miles for the ECU
to recognize the new one and adjust the engine management accordingly.
Does this sound right? Or I had a bad tank of gas.
ANSWER: It can take several drive cycles for the ECU to adapt. I would also suggest fuel injection cleaner in the fuel tank and an upper cylinder lubricant in the oil to free off the valves.
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QUESTION: Hi Nigel,
Jeff here again from Hawaii with the 02 Disco (66K). Well my misfires
continue on Cylinders 4 and 6. Found out from my mechanic that the O2
sensors were not replaced as I thought. Codes I'm getting in addition are
P0072, P0206, P0204, P0304, P0306, P1175 and P1172. Engine is running
progressively worse. Did a compression test on 4 and 6 cylinders. 75 and 65
PSI which looked good, Traded the back O2 sensors with each other to see if
that may be culprit. Same codes showed up on Bank 2 like before.My
mechanic wants me to replace all the fuel injectors but I have been told that
they were good injectors on the 02 Discos and rarely fail. Also, I noticed that
the the passenger side O2 sensor was wet (Water?) when I removed it
whereas the drivers side was really dry. Would a head gasket leak cause any
of this?
I'm monitoring the coolant closely now.
Thanks for any input!
Jeff
Answer65 and 75 psi on the compression is extremely low. They should be at least 120 on cranking. I would suggest you do a cylinder leakage test to find out where the compression leakage is. It still could be just the sticky valves I mentioned earlier. The cylinder leakage test will indicate the area of the failure, e.g. cylinder head, piston rings, valves, etc.
